If a device specifies zero endpoints in its interface descriptor,
the kernel oopses in acm_probe(). Even though that's clearly an
invalid descriptor, we should test wether we have all endpoints.
This is especially bad as this oops can be triggered by just
plugging a USB device in.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixed coding style issue related to
prohibited space in drivers/usb/class/cdc-acm.c
Signed-off-by: Jeffrin Jose <ahiliation@yahoo.co.in>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This lets us catch the USB fixes that went into 3.5-rc3 into this branch,
as we want them here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
qmi_wwan has been changed to drive both the control and data
interface for all QMI/wwan devices, using cdc-wdm as a subdriver.
Remove the stale device ID entries from cdc-wdm.
>From now on new QMI/wwan devices will only need to be added to
the qmi_wwan driver, regardless of the USB descriptor layout
Note that this is not appropriate for stable/longterm kernels
despite being a device ID patch.
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently CDC-ACM devices stay throttled when their TTY is closed while
throttled, stalling further communication attempts after the next open.
Unthrottling during open/activate got lost starting with kernel
3.0.0 and this patch reintroduces it.
Signed-off-by: Otto Meta <otto.patches@sister-shadow.de>
Cc: stable <stable@vger.kernel.org>
Acked-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Hub-initiated LPM is not good for USB communications devices. Comms
devices should be able to tell when their link can go into a lower power
state, because they know when an incoming transmission is finished.
Ideally, these devices would slam their links into a lower power state,
using the device-initiated LPM, after finishing the last packet of their
data transfer.
If we enable the idle timeouts for the parent hubs to enable
hub-initiated LPM, we will get a lot of useless LPM packets on the bus
as the devices reject LPM transitions when they're in the middle of
receiving data. Worse, some devices might blindly accept the
hub-initiated LPM and power down their radios while they're in the
middle of receiving a transmission.
The Intel Windows folks are disabling hub-initiated LPM for all USB
communications devices under a xHCI USB 3.0 host. In order to keep
the Linux behavior as close as possible to Windows, we need to do the
same in Linux.
Set the disable_hub_initiated_lpm flag for for all USB communications
drivers. I know there aren't currently any USB 3.0 devices that
implement these class specifications, but we should be ready if they do.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Hansjoerg Lipp <hjlipp@web.de>
Cc: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Jan Dumon <j.dumon@option.com>
Cc: Petko Manolov <petkan@users.sourceforge.net>
Cc: Steve Glendinning <steve.glendinning@smsc.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Cc: "Luis R. Rodriguez" <mcgrof@qca.qualcomm.com>
Cc: Jouni Malinen <jouni@qca.qualcomm.com>
Cc: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Cc: Senthil Balasubramanian <senthilb@qca.qualcomm.com>
Cc: Christian Lamparter <chunkeey@googlemail.com>
Cc: Brett Rudley <brudley@broadcom.com>
Cc: Roland Vossen <rvossen@broadcom.com>
Cc: Arend van Spriel <arend@broadcom.com>
Cc: "Franky (Zhenhui) Lin" <frankyl@broadcom.com>
Cc: Kan Yan <kanyan@broadcom.com>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Gertjan van Wingerde <gwingerde@gmail.com>
Cc: Helmut Schaa <helmut.schaa@googlemail.com>
Cc: Herton Ronaldo Krzesinski <herton@canonical.com>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Chaoming Li <chaoming_li@realsil.com.cn>
Cc: Daniel Drake <dsd@gentoo.org>
Cc: Ulrich Kunitz <kune@deine-taler.de>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Prevents dereferencing an invalid struct usb_interface
pointer.
Always delete entry from device list whether or not the
rest of the device state cleanup is postponed. The device
list uses desc->intf as key, and wdm_open will dereference
this key while searching for a matching device. A device
should not appear in the list unless probe() has succeeded
and disconnect() has not finished.
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We cannot dereference a removed USB interface for
dev_printk. Use pr_debug instead where necessary.
Flush errors are expected if device is unplugged and are
therefore best ingored at this point.
Move the kill_urbs() call in wdm_release with dev_dbg()
for the non disconnect, as we know it has already been
called if WDM_DISCONNECTING is set. This does not
actually fix anything, but keeps the code more consistent.
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Else the poll will be restarted indefinitely in a tight loop,
preventing final device cleanup.
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dbg() was a very old USB-specific macro that should no longer
be used. This patch removes it from being used in the driver
and uses dev_dbg() instead.
CC: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The internal error codes returned in the write() code
path cannot be simply passed on to user space.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Tested-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Device state cleanup is done in either wdm_disconnect or
wdm_release depending on the order they are called. Adding
a couple of debug messages to document the program flow.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cleanup() is not called if the last close() comes after
disconnect(). That leads to a memory leak. Rectified
by checking for an earlier disconnect() in release()
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
wdm_flush() returns unsanitized USB error codes.
They must be cleaned up to before being anded to user space
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fixes a race whereby a pointer to a buffer
would be overwritten while the buffer was in use leading
to a double free and a memory leak. This causes crashes.
This bug was introduced in 2.6.34
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Tested-by: Bjørn Mork <bjorn@mork.no>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here's the big USB merge for the 3.4-rc1 merge window.
Lots of gadget driver reworks here, driver updates, xhci changes, some
new drivers added, usb-serial core reworking to fix some bugs, and other
various minor things.
There are some patches touching arch code, but they have all been acked
by the various arch maintainers.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'usb-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
Pull USB merge for 3.4-rc1 from Greg KH:
"Here's the big USB merge for the 3.4-rc1 merge window.
Lots of gadget driver reworks here, driver updates, xhci changes, some
new drivers added, usb-serial core reworking to fix some bugs, and
other various minor things.
There are some patches touching arch code, but they have all been
acked by the various arch maintainers."
* tag 'usb-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (302 commits)
net: qmi_wwan: add support for ZTE MF820D
USB: option: add ZTE MF820D
usb: gadget: f_fs: Remove lock is held before freeing checks
USB: option: make interface blacklist work again
usb/ub: deprecate & schedule for removal the "Low Performance USB Block" driver
USB: ohci-pxa27x: add clk_prepare/clk_unprepare calls
USB: use generic platform driver on ath79
USB: EHCI: Add a generic platform device driver
USB: OHCI: Add a generic platform device driver
USB: ftdi_sio: new PID: LUMEL PD12
USB: ftdi_sio: add support for FT-X series devices
USB: serial: mos7840: Fixed MCS7820 device attach problem
usb: Don't make USB_ARCH_HAS_{XHCI,OHCI,EHCI} depend on USB_SUPPORT.
usb gadget: fix a section mismatch when compiling g_ffs with CONFIG_USB_FUNCTIONFS_ETH
USB: ohci-nxp: Remove i2c_write(), use smbus
USB: ohci-nxp: Support for LPC32xx
USB: ohci-nxp: Rename symbols from pnx4008 to nxp
USB: OHCI-HCD: Rename ohci-pnx4008 to ohci-nxp
usb: gadget: Kconfig: fix typo for 'different'
usb: dwc3: pci: fix another failure path in dwc3_pci_probe()
...
This driver can be used as a subdriver of another USB driver, allowing
it to export a Device Managment interface consisting of a single interrupt
endpoint with no dedicated USB interface.
Some devices provide a Device Management function combined with a wwan
function in a single USB interface having three endpoints (bulk in/out
+ interrupt). If the interrupt endpoint is used exclusively for DM
notifications, then this driver can support that as a subdriver
provided that the wwan driver calls the appropriate entry points on
probe, suspend, resume, pre_reset, post_reset and disconnect.
The main driver must have full control over all interface related
settings, including the needs_remote_wakeup flag. A manage_power
function must be provided by the main driver.
A manage_power stub doing direct flag manipulation is used in normal
driver mode.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Register all interfaces handled by this driver in a list, getting
rid of the dependency on usb_set_intfdata. This allows further
generalization and simplification of the probe/create functions.
This is needed to decouple wdm_open from the driver owning the
interface, and it also allows us to share all the code in
wdm_create with drivers unable to do usb_set_intfdata.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Preparing for the addition of subdriver registering as an alternative
to probe for interface-less usage. This should not change anything
apart from minor code reordering.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All num, magic and owner are set by alloc_tty_driver. No need to
re-set them on each allocation site.
pti driver sets something different to what it passes to
alloc_tty_driver. It is not a bug, since we don't use the lines
parameter in any way. Anyway this is fixed, and now we do the right
thing.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a piece I missed the last time.
Do not copy the functionality all over the tree. Instead, use the
helper the tty layer provides us with.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Oliver Neukum <oneukum@suse.de>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We had a user report that running setserial on /dev/ttyACM0 didn't work.
He pointed at an old patch by Oliver Neukum from 2008 that never went anywhere..
http://permalink.gmane.org/gmane.linux.usb.general/9236
I made some minor changes to get it to apply again, and got the user to retest on 3.1,
and he reported it worked for him. https://bugzilla.redhat.com/show_bug.cgi?id=787607
The diff below is against 3.3rc. The only difference between this and
the version the user tested is the removal of the if (!ACM_READY) test
Havard removed ACM_READY in 99823f457d
I'm unclear if there's need for a different test in its place.
From: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The WDM_READ flag is cleared later iff desc->length is reduced to 0.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Bjørn Mork <bjorn@mork.no>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We must not allow the input buffer length to change while we're
shuffling the buffer contents. We also mustn't clear the WDM_READ
flag after more data might have arrived. Therefore move both of these
into the spinlocked region at the bottom of wdm_read().
When reading desc->length without holding the iuspin lock, use
ACCESS_ONCE() to ensure the compiler doesn't re-read it with
inconsistent results.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Bjørn Mork <bjorn@mork.no>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a flag to tell wdm_read/wdm_write that a reset is in progress,
and wake any blocking read/write before taking the mutexes. This
allows the device to reset without waiting for blocking IO to
finish.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is done to resolve a merge conflict with:
drivers/usb/class/cdc-wdm.c
and to better handle future patches for this driver as it is under
active development at the moment.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[v2: Editorial changes suggested by Sergei Shtylyov]
These modems use the Qualcomm MSM Interface (QMI) protocol for
management of their CDC ECM like wwan interface. This driver
is perfect for exporting the protocol to userspace.
The created character device will be indistinguishable from a
common AT command based Device Management interface, so
userspace applications must do some intelligent matching
on the USB device.
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
usb_register_dev() will change our .minor_base to 0 if
CONFIG_USB_DYNAMIC_MINORS is set. And it usually is, of
course.
Use dev_name() to print the proper interface name instead
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The probe does not strictly require the USB_CDC_DMM_TYPE
descriptor, which is a good thing as it makes the driver
usable on non-conforming interfaces. A user could e.g.
bind to it to a CDC ECM interface by using the new_id and
bind sysfs files. But this would fail with a 0 buffer length
due to the missing descriptor.
Fix by defining a reasonable fallback size: The minimum
device receive buffer size required by the CDC WMC standard,
revision 1.1
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The probe does not strictly require the USB_CDC_DMM_TYPE
descriptor, which is a good thing as it makes the driver
usable on non-conforming interfaces. A user could e.g.
bind to it to a CDC ECM interface by using the new_id and
bind sysfs files. But this would fail with a 0 buffer length
due to the missing descriptor.
Fix by defining a reasonable fallback size: The minimum
device receive buffer size required by the CDC WMC standard,
revision 1.1
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We don't need bMaxPacketSize0, and keeping all these different size fields
around will only cause us to use the wrong one.
Seems the udev variable was only used for getting bMaxPacketSize0. We
could have used it for the usb_fill_*_urb() calls, but as it wasn't
before - why start now? Instead make the interface_to_usbdev()
calls consistent.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
As Documentation/usb/dma.txt states:
Most drivers should *NOT* be using these primitives; they don't need
to use this type of memory (dma-coherent), and memory returned from
kmalloc() will work just fine.
This driver handle only very low bandwith transfers. It is not an
obvious candidate for usb_alloc_coherent().
Using these calls only serves to complicate the code for no gain,
as has been shown by multiple bugs related to this allocation path.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
As it turns out, there was a mismatch between the allocated inbuf size
(desc->bMaxPacketSize0, typically something like 64) and the length we
specified in the URB (desc->wMaxCommand, typically something like 2048)
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Filling the same URB with the exact same data is pointless. It can be filled
once and resubmitted. And not doing buffer allocation and URB filling at the
same place only serves to hide size mismatch bugs
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
As it turns out, there was a mismatch between the allocated inbuf size
(desc->bMaxPacketSize0, typically something like 64) and the length we
specified in the URB (desc->wMaxCommand, typically something like 2048)
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
wdm_disconnect() waits for the mutex held by wdm_read() before
calling wake_up_all(). This causes a deadlock, preventing device removal
to complete. Do the wake_up_all() before we start waiting for the locks.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
using a separate read and write mutex for locking is sufficient to make the
driver accept simultaneous read and write. This improves useability a lot.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: stable <stable@vger.kernel.org>
Cc: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
wdm_in_callback() will also touch this field, so we cannot change it without locking
Cc: stable@vger.kernel.org
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (165 commits)
reiserfs: Properly display mount options in /proc/mounts
vfs: prevent remount read-only if pending removes
vfs: count unlinked inodes
vfs: protect remounting superblock read-only
vfs: keep list of mounts for each superblock
vfs: switch ->show_options() to struct dentry *
vfs: switch ->show_path() to struct dentry *
vfs: switch ->show_devname() to struct dentry *
vfs: switch ->show_stats to struct dentry *
switch security_path_chmod() to struct path *
vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb
vfs: trim includes a bit
switch mnt_namespace ->root to struct mount
vfs: take /proc/*/mounts and friends to fs/proc_namespace.c
vfs: opencode mntget() mnt_set_mountpoint()
vfs: spread struct mount - remaining argument of next_mnt()
vfs: move fsnotify junk to struct mount
vfs: move mnt_devname
vfs: move mnt_list to struct mount
vfs: switch pnode.h macros to struct mount *
...
This resolves the conflict in the arch/arm/mach-s3c64xx/s3c6400.c file,
and it fixes the build error in the arch/x86/kernel/microcode_core.c
file, that the merge did not catch.
The microcode_core.c patch was provided by Stephen Rothwell
<sfr@canb.auug.org.au> who was invaluable in the merge issues involved
with the large sysdev removal process in the driver-core tree.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On some failures, the country_code field of an acm structure is freed
without freeing the acm structure itself. Elsewhere, operations including
memcpy and kfree are performed on the country_code field. The patch sets
the country_code field to NULL when it is freed, and likewise sets the
country_code_size field to 0.
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Oliver Neukum <oneukum@suse.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add USB IDs for Motorola H24 HSPA USB module.
Signed-off-by: Krzysztof Hałasa <khalasa@piap.pl>
Acked-by: Oliver Neukum <oneukum@suse.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The ACM_READY() macro doesn't seem to do anything useful, and it may
prevent tty_wait_until_sent() from working properly when called from
close.
Previously, acm_tty_chars_in_buffer() returned 0 whenever
acm->port.count was 0. This means close() could return before all the
data has actually been written.
Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Rework the locking and lifecycle management in the cdc-acm driver.
Instead of using a global mutex to prevent the 'acm' object from being
freed, use the tty_port kref to keep the device alive when either the
USB side or TTY side is still active.
This allows us to use the global mutex purely for protecting the
acm_table, while use acm->mutex to guard against disconnect during
TTY port activation and shutdown.
The USB-side kref is taken during port initialization in probe(), and
released at the end of disconnect(). The TTY-side kref is taken in
install() and released in cleanup(). On disconnect, tty_vhangup() is
called instead of tty_hangup() to ensure the TTY hangup processing is
completed before the USB device is taken down.
The TTY open and close handlers have been gutted and replaced with
tty_port_open() and tty_port_close() respectively. The driver-specific
code which used to be there was spread across install(), activate() and
shutdown().
Reported-by: Dave Jones <davej@redhat.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
