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linux_dsm_epyc7002/drivers/tty/n_hdlc.c

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Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
/* generic HDLC line discipline for Linux
*
* Written by Paul Fulghum paulkf@microgate.com
* for Microgate Corporation
*
* Microgate and SyncLink are registered trademarks of Microgate Corporation
*
* Adapted from ppp.c, written by Michael Callahan <callahan@maths.ox.ac.uk>,
* Al Longyear <longyear@netcom.com>,
* Paul Mackerras <Paul.Mackerras@cs.anu.edu.au>
*
* Original release 01/11/99
*
* This code is released under the GNU General Public License (GPL)
*
* This module implements the tty line discipline N_HDLC for use with
* tty device drivers that support bit-synchronous HDLC communications.
*
* All HDLC data is frame oriented which means:
*
* 1. tty write calls represent one complete transmit frame of data
* The device driver should accept the complete frame or none of
* the frame (busy) in the write method. Each write call should have
* a byte count in the range of 2-65535 bytes (2 is min HDLC frame
* with 1 addr byte and 1 ctrl byte). The max byte count of 65535
* should include any crc bytes required. For example, when using
* CCITT CRC32, 4 crc bytes are required, so the maximum size frame
* the application may transmit is limited to 65531 bytes. For CCITT
* CRC16, the maximum application frame size would be 65533.
*
*
* 2. receive callbacks from the device driver represents
* one received frame. The device driver should bypass
* the tty flip buffer and call the line discipline receive
* callback directly to avoid fragmenting or concatenating
* multiple frames into a single receive callback.
*
* The HDLC line discipline queues the receive frames in separate
* buffers so complete receive frames can be returned by the
* tty read calls.
*
* 3. tty read calls returns an entire frame of data or nothing.
*
* 4. all send and receive data is considered raw. No processing
* or translation is performed by the line discipline, regardless
* of the tty flags
*
* 5. When line discipline is queried for the amount of receive
* data available (FIOC), 0 is returned if no data available,
* otherwise the count of the next available frame is returned.
* (instead of the sum of all received frame counts).
*
* These conventions allow the standard tty programming interface
* to be used for synchronous HDLC applications when used with
* this line discipline (or another line discipline that is frame
* oriented such as N_PPP).
*
* The SyncLink driver (synclink.c) implements both asynchronous
* (using standard line discipline N_TTY) and synchronous HDLC
* (using N_HDLC) communications, with the latter using the above
* conventions.
*
* This implementation is very basic and does not maintain
* any statistics. The main point is to enforce the raw data
* and frame orientation of HDLC communications.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#define HDLC_MAGIC 0x239e
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#undef VERSION
#define VERSION(major,minor,patch) (((((major)<<8)+(minor))<<8)+(patch))
#include <linux/poll.h>
#include <linux/in.h>
#include <linux/ioctl.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/string.h> /* used in new tty drivers */
#include <linux/signal.h> /* used in new tty drivers */
#include <linux/if.h>
#include <linux/bitops.h>
#include <asm/termios.h>
#include <asm/uaccess.h>
/*
* Buffers for individual HDLC frames
*/
#define MAX_HDLC_FRAME_SIZE 65535
#define DEFAULT_RX_BUF_COUNT 10
#define MAX_RX_BUF_COUNT 60
tty: n_hdlc add buffer flushing Add flush_buffer tty callback to flush rx buffers. Add TCFLSH ioctl processing to flush tx buffers. Increase default tx buffers from 1 to 3. Remove unneeded flush_buffer call in open callback. Remove vendor specific CVS version string. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-23 00:42:56 +07:00
#define DEFAULT_TX_BUF_COUNT 3
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
struct n_hdlc_buf {
struct n_hdlc_buf *link;
int count;
char buf[1];
};
#define N_HDLC_BUF_SIZE (sizeof(struct n_hdlc_buf) + maxframe)
struct n_hdlc_buf_list {
struct n_hdlc_buf *head;
struct n_hdlc_buf *tail;
int count;
spinlock_t spinlock;
};
/**
* struct n_hdlc - per device instance data structure
* @magic - magic value for structure
* @flags - miscellaneous control flags
* @tty - ptr to TTY structure
* @backup_tty - TTY to use if tty gets closed
* @tbusy - reentrancy flag for tx wakeup code
* @woke_up - FIXME: describe this field
* @tbuf - currently transmitting tx buffer
* @tx_buf_list - list of pending transmit frame buffers
* @rx_buf_list - list of received frame buffers
* @tx_free_buf_list - list unused transmit frame buffers
* @rx_free_buf_list - list unused received frame buffers
*/
struct n_hdlc {
int magic;
__u32 flags;
struct tty_struct *tty;
struct tty_struct *backup_tty;
int tbusy;
int woke_up;
struct n_hdlc_buf *tbuf;
struct n_hdlc_buf_list tx_buf_list;
struct n_hdlc_buf_list rx_buf_list;
struct n_hdlc_buf_list tx_free_buf_list;
struct n_hdlc_buf_list rx_free_buf_list;
};
/*
* HDLC buffer list manipulation functions
*/
static void n_hdlc_buf_put(struct n_hdlc_buf_list *list,
struct n_hdlc_buf *buf);
static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *list);
/* Local functions */
static struct n_hdlc *n_hdlc_alloc (void);
/* debug level can be set by insmod for debugging purposes */
#define DEBUG_LEVEL_INFO 1
static int debuglevel;
/* max frame size for memory allocations */
static int maxframe = 4096;
/* TTY callbacks */
static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
__u8 __user *buf, size_t nr);
static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
const unsigned char *buf, size_t nr);
static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg);
static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
poll_table *wait);
static int n_hdlc_tty_open(struct tty_struct *tty);
static void n_hdlc_tty_close(struct tty_struct *tty);
Revert "tty: make receive_buf() return the amout of bytes received" This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c. It was broken in so many ways, and results in random odd pty issues. It re-introduced the buggy schedule_work() in flush_to_ldisc() that can cause endless work-loops (see commit a5660b41af6a: "tty: fix endless work loop when the buffer fills up"). It also used an "unsigned int" return value fo the ->receive_buf() function, but then made multiple functions return a negative error code, and didn't actually check for the error in the caller. And it didn't actually work at all. BenH bisected down odd tty behavior to it: "It looks like the patch is causing some major malfunctions of the X server for me, possibly related to PTYs. For example, cat'ing a large file in a gnome terminal hangs the kernel for -minutes- in a loop of what looks like flush_to_ldisc/workqueue code, (some ftrace data in the quoted bits further down). ... Some more data: It -looks- like what happens is that the flush_to_ldisc work queue entry constantly re-queues itself (because the PTY is full ?) and the workqueue thread will basically loop forver calling it without ever scheduling, thus starving the consumer process that could have emptied the PTY." which is pretty much exactly the problem we fixed in a5660b41af6a. Milton Miller pointed out the 'unsigned int' issue. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Milton Miller <miltonm@bga.com> Cc: Stefan Bigler <stefan.bigler@keymile.com> Cc: Toby Gray <toby.gray@realvnc.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-04 04:33:24 +07:00
static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *cp,
char *fp, int count);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
static void n_hdlc_tty_wakeup(struct tty_struct *tty);
#define bset(p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f)))
#define tty2n_hdlc(tty) ((struct n_hdlc *) ((tty)->disc_data))
#define n_hdlc2tty(n_hdlc) ((n_hdlc)->tty)
tty: n_hdlc add buffer flushing Add flush_buffer tty callback to flush rx buffers. Add TCFLSH ioctl processing to flush tx buffers. Increase default tx buffers from 1 to 3. Remove unneeded flush_buffer call in open callback. Remove vendor specific CVS version string. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-23 00:42:56 +07:00
static void flush_rx_queue(struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
struct n_hdlc_buf *buf;
while ((buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)))
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, buf);
}
static void flush_tx_queue(struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
struct n_hdlc_buf *buf;
unsigned long flags;
while ((buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list)))
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, buf);
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->tbuf) {
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, n_hdlc->tbuf);
n_hdlc->tbuf = NULL;
}
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
}
tty: Ldisc revamp Move the line disciplines towards a conventional ->ops arrangement. For the moment the actual 'tty_ldisc' struct in the tty is kept as part of the tty struct but this can then be changed if it turns out that when it all settles down we want to refcount ldiscs separately to the tty. Pull the ldisc code out of /proc and put it with our ldisc code. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-17 03:53:12 +07:00
static struct tty_ldisc_ops n_hdlc_ldisc = {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
.owner = THIS_MODULE,
.magic = TTY_LDISC_MAGIC,
.name = "hdlc",
.open = n_hdlc_tty_open,
.close = n_hdlc_tty_close,
.read = n_hdlc_tty_read,
.write = n_hdlc_tty_write,
.ioctl = n_hdlc_tty_ioctl,
.poll = n_hdlc_tty_poll,
.receive_buf = n_hdlc_tty_receive,
.write_wakeup = n_hdlc_tty_wakeup,
tty: n_hdlc add buffer flushing Add flush_buffer tty callback to flush rx buffers. Add TCFLSH ioctl processing to flush tx buffers. Increase default tx buffers from 1 to 3. Remove unneeded flush_buffer call in open callback. Remove vendor specific CVS version string. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-23 00:42:56 +07:00
.flush_buffer = flush_rx_queue,
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
};
/**
* n_hdlc_release - release an n_hdlc per device line discipline info structure
* @n_hdlc - per device line discipline info structure
*/
static void n_hdlc_release(struct n_hdlc *n_hdlc)
{
struct tty_struct *tty = n_hdlc2tty (n_hdlc);
struct n_hdlc_buf *buf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_release() called\n",__FILE__,__LINE__);
/* Ensure that the n_hdlcd process is not hanging on select()/poll() */
wake_up_interruptible (&tty->read_wait);
wake_up_interruptible (&tty->write_wait);
n_hdlc.c: fix check-after-use The Coverity checker spotted that we'd have already oops'ed if "tty" was NULL. Since "tty" can't be NULL when we reach this line of code this patch removes the NULL check. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 13:29:25 +07:00
if (tty->disc_data == n_hdlc)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
tty->disc_data = NULL; /* Break the tty->n_hdlc link */
/* Release transmit and receive buffers */
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
[PATCH] kfree cleanup: drivers/char This is the drivers/char/ part of the big kfree cleanup patch. Remove pointless checks for NULL prior to calling kfree() in drivers/char/. Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 16:01:29 +07:00
kfree(n_hdlc->tbuf);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
kfree(n_hdlc);
} /* end of n_hdlc_release() */
/**
* n_hdlc_tty_close - line discipline close
* @tty - pointer to tty info structure
*
* Called when the line discipline is changed to something
* else, the tty is closed, or the tty detects a hangup.
*/
static void n_hdlc_tty_close(struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_close() called\n",__FILE__,__LINE__);
if (n_hdlc != NULL) {
if (n_hdlc->magic != HDLC_MAGIC) {
printk (KERN_WARNING"n_hdlc: trying to close unopened tty!\n");
return;
}
#if defined(TTY_NO_WRITE_SPLIT)
clear_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
#endif
tty->disc_data = NULL;
if (tty == n_hdlc->backup_tty)
n_hdlc->backup_tty = NULL;
if (tty != n_hdlc->tty)
return;
if (n_hdlc->backup_tty) {
n_hdlc->tty = n_hdlc->backup_tty;
} else {
n_hdlc_release (n_hdlc);
}
}
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_close() success\n",__FILE__,__LINE__);
} /* end of n_hdlc_tty_close() */
/**
* n_hdlc_tty_open - called when line discipline changed to n_hdlc
* @tty - pointer to tty info structure
*
* Returns 0 if success, otherwise error code
*/
static int n_hdlc_tty_open (struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_open() called (device=%s)\n",
__FILE__,__LINE__,
tty->name);
/* There should not be an existing table for this slot. */
if (n_hdlc) {
printk (KERN_ERR"n_hdlc_tty_open:tty already associated!\n" );
return -EEXIST;
}
n_hdlc = n_hdlc_alloc();
if (!n_hdlc) {
printk (KERN_ERR "n_hdlc_alloc failed\n");
return -ENFILE;
}
tty->disc_data = n_hdlc;
n_hdlc->tty = tty;
[PATCH] TTY layer buffering revamp The API and code have been through various bits of initial review by serial driver people but they definitely need to live somewhere for a while so the unconverted drivers can get knocked into shape, existing drivers that have been updated can be better tuned and bugs whacked out. This replaces the tty flip buffers with kmalloc objects in rings. In the normal situation for an IRQ driven serial port at typical speeds the behaviour is pretty much the same, two buffers end up allocated and the kernel cycles between them as before. When there are delays or at high speed we now behave far better as the buffer pool can grow a bit rather than lose characters. This also means that we can operate at higher speeds reliably. For drivers that receive characters in blocks (DMA based, USB and especially virtualisation) the layer allows a lot of driver specific code that works around the tty layer with private secondary queues to be removed. The IBM folks need this sort of layer, the smart serial port people do, the virtualisers do (because a virtualised tty typically operates at infinite speed rather than emulating 9600 baud). Finally many drivers had invalid and unsafe attempts to avoid buffer overflows by directly invoking tty methods extracted out of the innards of work queue structs. These are no longer needed and all go away. That fixes various random hangs with serial ports on overflow. The other change in here is to optimise the receive_room path that is used by some callers. It turns out that only one ldisc uses receive room except asa constant and it updates it far far less than the value is read. We thus make it a variable not a function call. I expect the code to contain bugs due to the size alone but I'll be watching and squashing them and feeding out new patches as it goes. Because the buffers now dynamically expand you should only run out of buffering when the kernel runs out of memory for real. That means a lot of the horrible hacks high performance drivers used to do just aren't needed any more. Description: tty_insert_flip_char is an old API and continues to work as before, as does tty_flip_buffer_push() [this is why many drivers dont need modification]. It does now also return the number of chars inserted There are also tty_buffer_request_room(tty, len) which asks for a buffer block of the length requested and returns the space found. This improves efficiency with hardware that knows how much to transfer. and tty_insert_flip_string_flags(tty, str, flags, len) to insert a string of characters and flags For a smart interface the usual code is len = tty_request_buffer_room(tty, amount_hardware_says); tty_insert_flip_string(tty, buffer_from_card, len); More description! At the moment tty buffers are attached directly to the tty. This is causing a lot of the problems related to tty layer locking, also problems at high speed and also with bursty data (such as occurs in virtualised environments) I'm working on ripping out the flip buffers and replacing them with a pool of dynamically allocated buffers. This allows both for old style "byte I/O" devices and also helps virtualisation and smart devices where large blocks of data suddenely materialise and need storing. So far so good. Lots of drivers reference tty->flip.*. Several of them also call directly and unsafely into function pointers it provides. This will all break. Most drivers can use tty_insert_flip_char which can be kept as an API but others need more. At the moment I've added the following interfaces, if people think more will be needed now is a good time to say int tty_buffer_request_room(tty, size) Try and ensure at least size bytes are available, returns actual room (may be zero). At the moment it just uses the flipbuf space but that will change. Repeated calls without characters being added are not cumulative. (ie if you call it with 1, 1, 1, and then 4 you'll have four characters of space. The other functions will also try and grow buffers in future but this will be a more efficient way when you know block sizes. int tty_insert_flip_char(tty, ch, flag) As before insert a character if there is room. Now returns 1 for success, 0 for failure. int tty_insert_flip_string(tty, str, len) Insert a block of non error characters. Returns the number inserted. int tty_prepare_flip_string(tty, strptr, len) Adjust the buffer to allow len characters to be added. Returns a buffer pointer in strptr and the length available. This allows for hardware that needs to use functions like insl or mencpy_fromio. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 11:54:13 +07:00
tty->receive_room = 65536;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
#if defined(TTY_NO_WRITE_SPLIT)
/* change tty_io write() to not split large writes into 8K chunks */
set_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
#endif
tty: n_hdlc add buffer flushing Add flush_buffer tty callback to flush rx buffers. Add TCFLSH ioctl processing to flush tx buffers. Increase default tx buffers from 1 to 3. Remove unneeded flush_buffer call in open callback. Remove vendor specific CVS version string. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-23 00:42:56 +07:00
/* flush receive data from driver */
tty: The big operations rework - Operations are now a shared const function block as with most other Linux objects - Introduce wrappers for some optional functions to get consistent behaviour - Wrap put_char which used to be patched by the tty layer - Document which functions are needed/optional - Make put_char report success/fail - Cache the driver->ops pointer in the tty as tty->ops - Remove various surplus lock calls we no longer need - Remove proc_write method as noted by Alexey Dobriyan - Introduce some missing sanity checks where certain driver/ldisc combinations would oops as they didn't check needed methods were present [akpm@linux-foundation.org: fix fs/compat_ioctl.c build] [akpm@linux-foundation.org: fix isicom] [akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build] [akpm@linux-foundation.org: fix kgdb] Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:54:13 +07:00
tty_driver_flush_buffer(tty);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_open() success\n",__FILE__,__LINE__);
return 0;
} /* end of n_tty_hdlc_open() */
/**
* n_hdlc_send_frames - send frames on pending send buffer list
* @n_hdlc - pointer to ldisc instance data
* @tty - pointer to tty instance data
*
* Send frames on pending send buffer list until the driver does not accept a
* frame (busy) this function is called after adding a frame to the send buffer
* list and by the tty wakeup callback.
*/
static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
{
register int actual;
unsigned long flags;
struct n_hdlc_buf *tbuf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_send_frames() called\n",__FILE__,__LINE__);
check_again:
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->tbusy) {
n_hdlc->woke_up = 1;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
return;
}
n_hdlc->tbusy = 1;
n_hdlc->woke_up = 0;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
/* get current transmit buffer or get new transmit */
/* buffer from list of pending transmit buffers */
tbuf = n_hdlc->tbuf;
if (!tbuf)
tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
while (tbuf) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)sending frame %p, count=%d\n",
__FILE__,__LINE__,tbuf,tbuf->count);
/* Send the next block of data to device */
tty: n_hdlc not atomic use tty->flags. N_HDLC can spoil tty->flags because use not atomic operations on tty->flags. I use n_hdlc line discipline and it happens. Signed-off-by: Ilya Zykov <ilya@ilyx.ru> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-07 14:32:46 +07:00
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
tty: The big operations rework - Operations are now a shared const function block as with most other Linux objects - Introduce wrappers for some optional functions to get consistent behaviour - Wrap put_char which used to be patched by the tty layer - Document which functions are needed/optional - Make put_char report success/fail - Cache the driver->ops pointer in the tty as tty->ops - Remove various surplus lock calls we no longer need - Remove proc_write method as noted by Alexey Dobriyan - Introduce some missing sanity checks where certain driver/ldisc combinations would oops as they didn't check needed methods were present [akpm@linux-foundation.org: fix fs/compat_ioctl.c build] [akpm@linux-foundation.org: fix isicom] [akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build] [akpm@linux-foundation.org: fix kgdb] Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:54:13 +07:00
actual = tty->ops->write(tty, tbuf->buf, tbuf->count);
Char: n_hdlc, allow RESTARTSYS retval of tty write Acked-by: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 13:40:12 +07:00
/* rollback was possible and has been done */
if (actual == -ERESTARTSYS) {
n_hdlc->tbuf = tbuf;
break;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
/* if transmit error, throw frame away by */
/* pretending it was accepted by driver */
if (actual < 0)
actual = tbuf->count;
if (actual == tbuf->count) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)frame %p completed\n",
__FILE__,__LINE__,tbuf);
/* free current transmit buffer */
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, tbuf);
/* this tx buffer is done */
n_hdlc->tbuf = NULL;
/* wait up sleeping writers */
wake_up_interruptible(&tty->write_wait);
/* get next pending transmit buffer */
tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
} else {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)frame %p pending\n",
__FILE__,__LINE__,tbuf);
/* buffer not accepted by driver */
/* set this buffer as pending buffer */
n_hdlc->tbuf = tbuf;
break;
}
}
if (!tbuf)
tty: n_hdlc not atomic use tty->flags. N_HDLC can spoil tty->flags because use not atomic operations on tty->flags. I use n_hdlc line discipline and it happens. Signed-off-by: Ilya Zykov <ilya@ilyx.ru> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-07 14:32:46 +07:00
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
/* Clear the re-entry flag */
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
n_hdlc->tbusy = 0;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->woke_up)
goto check_again;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_send_frames() exit\n",__FILE__,__LINE__);
} /* end of n_hdlc_send_frames() */
/**
* n_hdlc_tty_wakeup - Callback for transmit wakeup
* @tty - pointer to associated tty instance data
*
* Called when low level device driver can accept more send data.
*/
static void n_hdlc_tty_wakeup(struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_wakeup() called\n",__FILE__,__LINE__);
if (!n_hdlc)
return;
if (tty != n_hdlc->tty) {
tty: n_hdlc not atomic use tty->flags. N_HDLC can spoil tty->flags because use not atomic operations on tty->flags. I use n_hdlc line discipline and it happens. Signed-off-by: Ilya Zykov <ilya@ilyx.ru> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-07 14:32:46 +07:00
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
return;
}
n_hdlc_send_frames (n_hdlc, tty);
} /* end of n_hdlc_tty_wakeup() */
/**
* n_hdlc_tty_receive - Called by tty driver when receive data is available
* @tty - pointer to tty instance data
* @data - pointer to received data
* @flags - pointer to flags for data
* @count - count of received data in bytes
*
* Called by tty low level driver when receive data is available. Data is
* interpreted as one HDLC frame.
*/
Revert "tty: make receive_buf() return the amout of bytes received" This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c. It was broken in so many ways, and results in random odd pty issues. It re-introduced the buggy schedule_work() in flush_to_ldisc() that can cause endless work-loops (see commit a5660b41af6a: "tty: fix endless work loop when the buffer fills up"). It also used an "unsigned int" return value fo the ->receive_buf() function, but then made multiple functions return a negative error code, and didn't actually check for the error in the caller. And it didn't actually work at all. BenH bisected down odd tty behavior to it: "It looks like the patch is causing some major malfunctions of the X server for me, possibly related to PTYs. For example, cat'ing a large file in a gnome terminal hangs the kernel for -minutes- in a loop of what looks like flush_to_ldisc/workqueue code, (some ftrace data in the quoted bits further down). ... Some more data: It -looks- like what happens is that the flush_to_ldisc work queue entry constantly re-queues itself (because the PTY is full ?) and the workqueue thread will basically loop forver calling it without ever scheduling, thus starving the consumer process that could have emptied the PTY." which is pretty much exactly the problem we fixed in a5660b41af6a. Milton Miller pointed out the 'unsigned int' issue. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Milton Miller <miltonm@bga.com> Cc: Stefan Bigler <stefan.bigler@keymile.com> Cc: Toby Gray <toby.gray@realvnc.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-04 04:33:24 +07:00
static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,
char *flags, int count)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
{
register struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
register struct n_hdlc_buf *buf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_receive() called count=%d\n",
__FILE__,__LINE__, count);
/* This can happen if stuff comes in on the backup tty */
drivers: fix integer as NULL pointer warnings Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 06:50:04 +07:00
if (!n_hdlc || tty != n_hdlc->tty)
Revert "tty: make receive_buf() return the amout of bytes received" This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c. It was broken in so many ways, and results in random odd pty issues. It re-introduced the buggy schedule_work() in flush_to_ldisc() that can cause endless work-loops (see commit a5660b41af6a: "tty: fix endless work loop when the buffer fills up"). It also used an "unsigned int" return value fo the ->receive_buf() function, but then made multiple functions return a negative error code, and didn't actually check for the error in the caller. And it didn't actually work at all. BenH bisected down odd tty behavior to it: "It looks like the patch is causing some major malfunctions of the X server for me, possibly related to PTYs. For example, cat'ing a large file in a gnome terminal hangs the kernel for -minutes- in a loop of what looks like flush_to_ldisc/workqueue code, (some ftrace data in the quoted bits further down). ... Some more data: It -looks- like what happens is that the flush_to_ldisc work queue entry constantly re-queues itself (because the PTY is full ?) and the workqueue thread will basically loop forver calling it without ever scheduling, thus starving the consumer process that could have emptied the PTY." which is pretty much exactly the problem we fixed in a5660b41af6a. Milton Miller pointed out the 'unsigned int' issue. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Milton Miller <miltonm@bga.com> Cc: Stefan Bigler <stefan.bigler@keymile.com> Cc: Toby Gray <toby.gray@realvnc.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-04 04:33:24 +07:00
return;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
/* verify line is using HDLC discipline */
if (n_hdlc->magic != HDLC_MAGIC) {
printk("%s(%d) line not using HDLC discipline\n",
__FILE__,__LINE__);
Revert "tty: make receive_buf() return the amout of bytes received" This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c. It was broken in so many ways, and results in random odd pty issues. It re-introduced the buggy schedule_work() in flush_to_ldisc() that can cause endless work-loops (see commit a5660b41af6a: "tty: fix endless work loop when the buffer fills up"). It also used an "unsigned int" return value fo the ->receive_buf() function, but then made multiple functions return a negative error code, and didn't actually check for the error in the caller. And it didn't actually work at all. BenH bisected down odd tty behavior to it: "It looks like the patch is causing some major malfunctions of the X server for me, possibly related to PTYs. For example, cat'ing a large file in a gnome terminal hangs the kernel for -minutes- in a loop of what looks like flush_to_ldisc/workqueue code, (some ftrace data in the quoted bits further down). ... Some more data: It -looks- like what happens is that the flush_to_ldisc work queue entry constantly re-queues itself (because the PTY is full ?) and the workqueue thread will basically loop forver calling it without ever scheduling, thus starving the consumer process that could have emptied the PTY." which is pretty much exactly the problem we fixed in a5660b41af6a. Milton Miller pointed out the 'unsigned int' issue. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Milton Miller <miltonm@bga.com> Cc: Stefan Bigler <stefan.bigler@keymile.com> Cc: Toby Gray <toby.gray@realvnc.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-04 04:33:24 +07:00
return;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
}
if ( count>maxframe ) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d) rx count>maxframesize, data discarded\n",
__FILE__,__LINE__);
Revert "tty: make receive_buf() return the amout of bytes received" This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c. It was broken in so many ways, and results in random odd pty issues. It re-introduced the buggy schedule_work() in flush_to_ldisc() that can cause endless work-loops (see commit a5660b41af6a: "tty: fix endless work loop when the buffer fills up"). It also used an "unsigned int" return value fo the ->receive_buf() function, but then made multiple functions return a negative error code, and didn't actually check for the error in the caller. And it didn't actually work at all. BenH bisected down odd tty behavior to it: "It looks like the patch is causing some major malfunctions of the X server for me, possibly related to PTYs. For example, cat'ing a large file in a gnome terminal hangs the kernel for -minutes- in a loop of what looks like flush_to_ldisc/workqueue code, (some ftrace data in the quoted bits further down). ... Some more data: It -looks- like what happens is that the flush_to_ldisc work queue entry constantly re-queues itself (because the PTY is full ?) and the workqueue thread will basically loop forver calling it without ever scheduling, thus starving the consumer process that could have emptied the PTY." which is pretty much exactly the problem we fixed in a5660b41af6a. Milton Miller pointed out the 'unsigned int' issue. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Milton Miller <miltonm@bga.com> Cc: Stefan Bigler <stefan.bigler@keymile.com> Cc: Toby Gray <toby.gray@realvnc.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-04 04:33:24 +07:00
return;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
}
/* get a free HDLC buffer */
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
if (!buf) {
/* no buffers in free list, attempt to allocate another rx buffer */
/* unless the maximum count has been reached */
if (n_hdlc->rx_buf_list.count < MAX_RX_BUF_COUNT)
buf = kmalloc(N_HDLC_BUF_SIZE, GFP_ATOMIC);
}
if (!buf) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d) no more rx buffers, data discarded\n",
__FILE__,__LINE__);
Revert "tty: make receive_buf() return the amout of bytes received" This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c. It was broken in so many ways, and results in random odd pty issues. It re-introduced the buggy schedule_work() in flush_to_ldisc() that can cause endless work-loops (see commit a5660b41af6a: "tty: fix endless work loop when the buffer fills up"). It also used an "unsigned int" return value fo the ->receive_buf() function, but then made multiple functions return a negative error code, and didn't actually check for the error in the caller. And it didn't actually work at all. BenH bisected down odd tty behavior to it: "It looks like the patch is causing some major malfunctions of the X server for me, possibly related to PTYs. For example, cat'ing a large file in a gnome terminal hangs the kernel for -minutes- in a loop of what looks like flush_to_ldisc/workqueue code, (some ftrace data in the quoted bits further down). ... Some more data: It -looks- like what happens is that the flush_to_ldisc work queue entry constantly re-queues itself (because the PTY is full ?) and the workqueue thread will basically loop forver calling it without ever scheduling, thus starving the consumer process that could have emptied the PTY." which is pretty much exactly the problem we fixed in a5660b41af6a. Milton Miller pointed out the 'unsigned int' issue. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Milton Miller <miltonm@bga.com> Cc: Stefan Bigler <stefan.bigler@keymile.com> Cc: Toby Gray <toby.gray@realvnc.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-04 04:33:24 +07:00
return;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
}
/* copy received data to HDLC buffer */
memcpy(buf->buf,data,count);
buf->count=count;
/* add HDLC buffer to list of received frames */
n_hdlc_buf_put(&n_hdlc->rx_buf_list, buf);
/* wake up any blocked reads and perform async signalling */
wake_up_interruptible (&tty->read_wait);
if (n_hdlc->tty->fasync != NULL)
kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN);
} /* end of n_hdlc_tty_receive() */
/**
s/retreiv/retriev/g As everyone knows, the rule is: "i before e.. um.. always." Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-01-03 19:27:11 +07:00
* n_hdlc_tty_read - Called to retrieve one frame of data (if available)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
* @tty - pointer to tty instance data
* @file - pointer to open file object
* @buf - pointer to returned data buffer
* @nr - size of returned data buffer
*
* Returns the number of bytes returned or error code.
*/
static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
__u8 __user *buf, size_t nr)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
int ret = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
struct n_hdlc_buf *rbuf;
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
DECLARE_WAITQUEUE(wait, current);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__);
/* Validate the pointers */
if (!n_hdlc)
return -EIO;
/* verify user access to buffer */
if (!access_ok(VERIFY_WRITE, buf, nr)) {
printk(KERN_WARNING "%s(%d) n_hdlc_tty_read() can't verify user "
"buffer\n", __FILE__, __LINE__);
return -EFAULT;
}
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
add_wait_queue(&tty->read_wait, &wait);
tty: BKL pushdown - Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:53:29 +07:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
for (;;) {
Fix OpenSSH pty regression on close OpenSSH expects the (non-blocking) read() of pty master to return EAGAIN only if it has received all of the slave-side output after it has received SIGCHLD. This used to work on pre-3.12 kernels. This fix effectively forces non-blocking read() and poll() to block for parallel i/o to complete for all ttys. It also unwinds these changes: 1) f8747d4a466ab2cafe56112c51b3379f9fdb7a12 tty: Fix pty master read() after slave closes 2) 52bce7f8d4fc633c9a9d0646eef58ba6ae9a3b73 pty, n_tty: Simplify input processing on final close 3) 1a48632ffed61352a7810ce089dc5a8bcd505a60 pty: Fix input race when closing Inspired by analysis and patch from Marc Aurele La France <tsi@tuyoix.net> Reported-by: Volth <openssh@volth.com> Reported-by: Marc Aurele La France <tsi@tuyoix.net> BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=52 BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=2492 Signed-off-by: Brian Bloniarz <brian.bloniarz@gmail.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-07 04:16:30 +07:00
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
ret = -EIO;
break;
tty: BKL pushdown - Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:53:29 +07:00
}
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
if (tty_hung_up_p(file))
break;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
set_current_state(TASK_INTERRUPTIBLE);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
if (rbuf) {
if (rbuf->count > nr) {
/* too large for caller's buffer */
ret = -EOVERFLOW;
} else {
if (copy_to_user(buf, rbuf->buf, rbuf->count))
ret = -EFAULT;
else
ret = rbuf->count;
}
if (n_hdlc->rx_free_buf_list.count >
DEFAULT_RX_BUF_COUNT)
kfree(rbuf);
else
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
break;
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
/* no data */
tty: BKL pushdown - Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:53:29 +07:00
if (file->f_flags & O_NONBLOCK) {
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
ret = -EAGAIN;
break;
tty: BKL pushdown - Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:53:29 +07:00
}
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
schedule();
tty: BKL pushdown - Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:53:29 +07:00
if (signal_pending(current)) {
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
ret = -EINTR;
break;
tty: BKL pushdown - Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:53:29 +07:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
}
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
remove_wait_queue(&tty->read_wait, &wait);
__set_current_state(TASK_RUNNING);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
return ret;
} /* end of n_hdlc_tty_read() */
/**
* n_hdlc_tty_write - write a single frame of data to device
* @tty - pointer to associated tty device instance data
* @file - pointer to file object data
* @data - pointer to transmit data (one frame)
* @count - size of transmit frame in bytes
*
* Returns the number of bytes written (or error code).
*/
static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
const unsigned char *data, size_t count)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
int error = 0;
DECLARE_WAITQUEUE(wait, current);
struct n_hdlc_buf *tbuf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_write() called count=%Zd\n",
__FILE__,__LINE__,count);
/* Verify pointers */
if (!n_hdlc)
return -EIO;
if (n_hdlc->magic != HDLC_MAGIC)
return -EIO;
/* verify frame size */
if (count > maxframe ) {
if (debuglevel & DEBUG_LEVEL_INFO)
printk (KERN_WARNING
"n_hdlc_tty_write: truncating user packet "
"from %lu to %d\n", (unsigned long) count,
maxframe );
count = maxframe;
}
add_wait_queue(&tty->write_wait, &wait);
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
if (tbuf)
break;
n_hdlc: honor O_NONBLOCK on write Make n_hdlc line discipline honor the O_NONBLOCK file flag on write. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-22 17:21:19 +07:00
if (file->f_flags & O_NONBLOCK) {
error = -EAGAIN;
break;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
schedule();
n_hdlc = tty2n_hdlc (tty);
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
tty != n_hdlc->tty) {
printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc);
error = -EIO;
break;
}
if (signal_pending(current)) {
error = -EINTR;
break;
}
}
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
__set_current_state(TASK_RUNNING);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
remove_wait_queue(&tty->write_wait, &wait);
if (!error) {
/* Retrieve the user's buffer */
memcpy(tbuf->buf, data, count);
/* Send the data */
tbuf->count = error = count;
n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf);
n_hdlc_send_frames(n_hdlc,tty);
}
n_hdlc: fix read and write locking Fix locking in read and write code of n_hdlc line discipline. 2.6.36 replaced lock_kernel() with tty_lock(). The tty mutex is not dropped automatically when the thread sleeps like the BKL. This results in a blocked read or write holding the tty mutex and stalling operations by other devices that use the tty mutex. A review of n_hdlc read and write code shows: 1. neither BKL or tty mutex are required for correct operation 2. read can block while read data is available if data is posted between availability check and call to interruptible_sleep_on() 3. write does not set process state to TASK_INTERRUPTIBLE on each pass through the processing loop which can cause unneeded scheduling of the thread The unnecessary tty mutex references have been removed. Read changed to use same code as n_tty read for completing reads and blocking. Write corrected to set process state to TASK_INTERRUPTIBLE on each pass through processing loop. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-19 05:03:25 +07:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
return error;
} /* end of n_hdlc_tty_write() */
/**
* n_hdlc_tty_ioctl - process IOCTL system call for the tty device.
* @tty - pointer to tty instance data
* @file - pointer to open file object for device
* @cmd - IOCTL command code
* @arg - argument for IOCTL call (cmd dependent)
*
* Returns command dependent result.
*/
static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
int error = 0;
int count;
unsigned long flags;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_ioctl() called %d\n",
__FILE__,__LINE__,cmd);
/* Verify the status of the device */
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC)
return -EBADF;
switch (cmd) {
case FIONREAD:
/* report count of read data available */
/* in next available frame (if any) */
spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags);
if (n_hdlc->rx_buf_list.head)
count = n_hdlc->rx_buf_list.head->count;
else
count = 0;
spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags);
error = put_user(count, (int __user *)arg);
break;
case TIOCOUTQ:
/* get the pending tx byte count in the driver */
tty: The big operations rework - Operations are now a shared const function block as with most other Linux objects - Introduce wrappers for some optional functions to get consistent behaviour - Wrap put_char which used to be patched by the tty layer - Document which functions are needed/optional - Make put_char report success/fail - Cache the driver->ops pointer in the tty as tty->ops - Remove various surplus lock calls we no longer need - Remove proc_write method as noted by Alexey Dobriyan - Introduce some missing sanity checks where certain driver/ldisc combinations would oops as they didn't check needed methods were present [akpm@linux-foundation.org: fix fs/compat_ioctl.c build] [akpm@linux-foundation.org: fix isicom] [akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build] [akpm@linux-foundation.org: fix kgdb] Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 14:54:13 +07:00
count = tty_chars_in_buffer(tty);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
/* add size of next output frame in queue */
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags);
if (n_hdlc->tx_buf_list.head)
count += n_hdlc->tx_buf_list.head->count;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags);
error = put_user(count, (int __user *)arg);
break;
tty: n_hdlc add buffer flushing Add flush_buffer tty callback to flush rx buffers. Add TCFLSH ioctl processing to flush tx buffers. Increase default tx buffers from 1 to 3. Remove unneeded flush_buffer call in open callback. Remove vendor specific CVS version string. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-23 00:42:56 +07:00
case TCFLSH:
switch (arg) {
case TCIOFLUSH:
case TCOFLUSH:
flush_tx_queue(tty);
}
/* fall through to default */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
default:
tty: some ICANON magic is in the wrong places Move the set up on ldisc change into the ldisc Move the INQ/OUTQ cases into the driver not in shared ioctl code where it gives bogus answers for other ldisc values Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 16:44:17 +07:00
error = n_tty_ioctl_helper(tty, file, cmd, arg);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
break;
}
return error;
} /* end of n_hdlc_tty_ioctl() */
/**
* n_hdlc_tty_poll - TTY callback for poll system call
* @tty - pointer to tty instance data
* @filp - pointer to open file object for device
* @poll_table - wait queue for operations
*
* Determine which operations (read/write) will not block and return info
* to caller.
* Returns a bit mask containing info on which ops will not block.
*/
static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
poll_table *wait)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
unsigned int mask = 0;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_poll() called\n",__FILE__,__LINE__);
if (n_hdlc && n_hdlc->magic == HDLC_MAGIC && tty == n_hdlc->tty) {
/* queue current process into any wait queue that */
/* may awaken in the future (read and write) */
poll_wait(filp, &tty->read_wait, wait);
poll_wait(filp, &tty->write_wait, wait);
/* set bits for operations that won't block */
Prevent an O_NDELAY writer from blocking when a tty write is blocked by the tty atomic writer mutex Without this a tty write could block if a previous blocking tty write was in progress on the same tty and blocked by a line discipline or hardware event. Originally found and reported by Dave Johnson. Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Dave Johnson <djohnson+linux-kernel@sw.starentnetworks.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 13:39:43 +07:00
if (n_hdlc->rx_buf_list.head)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
mask |= POLLIN | POLLRDNORM; /* readable */
Fix OpenSSH pty regression on close OpenSSH expects the (non-blocking) read() of pty master to return EAGAIN only if it has received all of the slave-side output after it has received SIGCHLD. This used to work on pre-3.12 kernels. This fix effectively forces non-blocking read() and poll() to block for parallel i/o to complete for all ttys. It also unwinds these changes: 1) f8747d4a466ab2cafe56112c51b3379f9fdb7a12 tty: Fix pty master read() after slave closes 2) 52bce7f8d4fc633c9a9d0646eef58ba6ae9a3b73 pty, n_tty: Simplify input processing on final close 3) 1a48632ffed61352a7810ce089dc5a8bcd505a60 pty: Fix input race when closing Inspired by analysis and patch from Marc Aurele La France <tsi@tuyoix.net> Reported-by: Volth <openssh@volth.com> Reported-by: Marc Aurele La France <tsi@tuyoix.net> BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=52 BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=2492 Signed-off-by: Brian Bloniarz <brian.bloniarz@gmail.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-07 04:16:30 +07:00
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
mask |= POLLHUP;
Prevent an O_NDELAY writer from blocking when a tty write is blocked by the tty atomic writer mutex Without this a tty write could block if a previous blocking tty write was in progress on the same tty and blocked by a line discipline or hardware event. Originally found and reported by Dave Johnson. Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Dave Johnson <djohnson+linux-kernel@sw.starentnetworks.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 13:39:43 +07:00
if (tty_hung_up_p(filp))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
mask |= POLLHUP;
Prevent an O_NDELAY writer from blocking when a tty write is blocked by the tty atomic writer mutex Without this a tty write could block if a previous blocking tty write was in progress on the same tty and blocked by a line discipline or hardware event. Originally found and reported by Dave Johnson. Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Dave Johnson <djohnson+linux-kernel@sw.starentnetworks.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 13:39:43 +07:00
if (!tty_is_writelocked(tty) &&
n_hdlc->tx_free_buf_list.head)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
mask |= POLLOUT | POLLWRNORM; /* writable */
}
return mask;
} /* end of n_hdlc_tty_poll() */
/**
* n_hdlc_alloc - allocate an n_hdlc instance data structure
*
* Returns a pointer to newly created structure if success, otherwise %NULL
*/
static struct n_hdlc *n_hdlc_alloc(void)
{
struct n_hdlc_buf *buf;
int i;
drivers/tty/n_hdlc.c: replace kmalloc/memset by kzalloc Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-27 02:32:42 +07:00
struct n_hdlc *n_hdlc = kzalloc(sizeof(*n_hdlc), GFP_KERNEL);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
if (!n_hdlc)
return NULL;
TTY: n_hdlc, fix lockdep false positive The class of 4 n_hdls buf locks is the same because a single function n_hdlc_buf_list_init is used to init all the locks. But since flush_tx_queue takes n_hdlc->tx_buf_list.spinlock and then calls n_hdlc_buf_put which takes n_hdlc->tx_free_buf_list.spinlock, lockdep emits a warning: ============================================= [ INFO: possible recursive locking detected ] 4.3.0-25.g91e30a7-default #1 Not tainted --------------------------------------------- a.out/1248 is trying to acquire lock: (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc] but task is already holding lock: (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&list->spinlock)->rlock); lock(&(&list->spinlock)->rlock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by a.out/1248: #0: (&tty->ldisc_sem){++++++}, at: [<ffffffff814c9eb0>] tty_ldisc_ref_wait+0x20/0x50 #1: (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc] ... Call Trace: ... [<ffffffff81738fd0>] _raw_spin_lock_irqsave+0x50/0x70 [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc] [<ffffffffa01fdc24>] n_hdlc_tty_ioctl+0x144/0x1d0 [n_hdlc] [<ffffffff814c25c1>] tty_ioctl+0x3f1/0xe40 ... Fix it by initializing the spin_locks separately. This removes also reduntand memset of a freshly kzallocated space. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-11-27 01:28:26 +07:00
spin_lock_init(&n_hdlc->rx_free_buf_list.spinlock);
spin_lock_init(&n_hdlc->tx_free_buf_list.spinlock);
spin_lock_init(&n_hdlc->rx_buf_list.spinlock);
spin_lock_init(&n_hdlc->tx_buf_list.spinlock);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
/* allocate free rx buffer list */
for(i=0;i<DEFAULT_RX_BUF_COUNT;i++) {
buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL);
if (buf)
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,buf);
else if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_alloc(), kalloc() failed for rx buffer %d\n",__FILE__,__LINE__, i);
}
/* allocate free tx buffer list */
for(i=0;i<DEFAULT_TX_BUF_COUNT;i++) {
buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL);
if (buf)
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list,buf);
else if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_alloc(), kalloc() failed for tx buffer %d\n",__FILE__,__LINE__, i);
}
/* Initialize the control block */
n_hdlc->magic = HDLC_MAGIC;
n_hdlc->flags = 0;
return n_hdlc;
} /* end of n_hdlc_alloc() */
/**
* n_hdlc_buf_put - add specified HDLC buffer to tail of specified list
* @list - pointer to buffer list
* @buf - pointer to buffer
*/
static void n_hdlc_buf_put(struct n_hdlc_buf_list *list,
struct n_hdlc_buf *buf)
{
unsigned long flags;
spin_lock_irqsave(&list->spinlock,flags);
buf->link=NULL;
Prevent an O_NDELAY writer from blocking when a tty write is blocked by the tty atomic writer mutex Without this a tty write could block if a previous blocking tty write was in progress on the same tty and blocked by a line discipline or hardware event. Originally found and reported by Dave Johnson. Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Dave Johnson <djohnson+linux-kernel@sw.starentnetworks.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 13:39:43 +07:00
if (list->tail)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
list->tail->link = buf;
else
list->head = buf;
list->tail = buf;
(list->count)++;
spin_unlock_irqrestore(&list->spinlock,flags);
} /* end of n_hdlc_buf_put() */
/**
* n_hdlc_buf_get - remove and return an HDLC buffer from list
* @list - pointer to HDLC buffer list
*
* Remove and return an HDLC buffer from the head of the specified HDLC buffer
* list.
* Returns a pointer to HDLC buffer if available, otherwise %NULL.
*/
static struct n_hdlc_buf* n_hdlc_buf_get(struct n_hdlc_buf_list *list)
{
unsigned long flags;
struct n_hdlc_buf *buf;
spin_lock_irqsave(&list->spinlock,flags);
buf = list->head;
if (buf) {
list->head = buf->link;
(list->count)--;
}
if (!list->head)
list->tail = NULL;
spin_unlock_irqrestore(&list->spinlock,flags);
return buf;
} /* end of n_hdlc_buf_get() */
static char hdlc_banner[] __initdata =
tty: n_hdlc add buffer flushing Add flush_buffer tty callback to flush rx buffers. Add TCFLSH ioctl processing to flush tx buffers. Increase default tx buffers from 1 to 3. Remove unneeded flush_buffer call in open callback. Remove vendor specific CVS version string. Signed-off-by: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-23 00:42:56 +07:00
KERN_INFO "HDLC line discipline maxframe=%u\n";
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
static char hdlc_register_ok[] __initdata =
KERN_INFO "N_HDLC line discipline registered.\n";
static char hdlc_register_fail[] __initdata =
KERN_ERR "error registering line discipline: %d\n";
static int __init n_hdlc_init(void)
{
int status;
/* range check maxframe arg */
if (maxframe < 4096)
maxframe = 4096;
else if (maxframe > 65535)
maxframe = 65535;
printk(hdlc_banner, maxframe);
status = tty_register_ldisc(N_HDLC, &n_hdlc_ldisc);
if (!status)
printk(hdlc_register_ok);
else
printk(hdlc_register_fail, status);
return status;
} /* end of init_module() */
static char hdlc_unregister_ok[] __exitdata =
KERN_INFO "N_HDLC: line discipline unregistered\n";
static char hdlc_unregister_fail[] __exitdata =
KERN_ERR "N_HDLC: can't unregister line discipline (err = %d)\n";
static void __exit n_hdlc_exit(void)
{
/* Release tty registration of line discipline */
[PATCH] Convert users to tty_unregister_ldisc() tty_register_ldisc(N_FOO, NULL) => tty_unregister_ldisc(N_FOO) Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 14:10:33 +07:00
int status = tty_unregister_ldisc(N_HDLC);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 05:20:36 +07:00
if (status)
printk(hdlc_unregister_fail, status);
else
printk(hdlc_unregister_ok);
}
module_init(n_hdlc_init);
module_exit(n_hdlc_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul Fulghum paulkf@microgate.com");
module_param(debuglevel, int, 0);
module_param(maxframe, int, 0);
MODULE_ALIAS_LDISC(N_HDLC);
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