If a dax buffer from a device that does not map pages is passed to
read(2) or write(2) as a target for direct-I/O it triggers SIGBUS. If
gdb attempts to examine the contents of a dax buffer from a device that
does not map pages it triggers SIGBUS. If fork(2) is called on a process
with a dax mapping from a device that does not map pages it triggers
SIGBUS. 'struct page' is required otherwise several kernel code paths
break in surprising ways. Disable filesystem-dax on devices that do not
map pages.
In addition to needing pfn_to_page() to be valid we also require devmap
pages. We need this to detect dax pages in the get_user_pages_fast()
path and so that we can stop managing the VM_MIXEDMAP flag. For DAX
drivers that have not supported get_user_pages() to date we allow them
to opt-in to supporting DAX with the CONFIG_FS_DAX_LIMITED configuration
option which requires ->direct_access() to return pfn_t_special() pfns.
This leaves DAX support in brd disabled and scheduled for removal.
Note that when the initial dax support was being merged a few years back
there was concern that struct page was unsuitable for use with next
generation persistent memory devices. The theoretical concern was that
struct page access, being such a hotly used data structure in the
kernel, would lead to media wear out. While that was a reasonable
conservative starting position it has not held true in practice. We have
long since committed to using devm_memremap_pages() to support higher
order kernel functionality that needs get_user_pages() and
pfn_to_page().
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add the correct SPDX license to a few more files under arch/s390 and
drivers/s390 which have been missed to far.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove CONFIG_SCM_BLOCK_CLUSTER_WRITE and related code. This quirk is
no longer needed on current hardware.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Setup a dax_dev to have the same lifetime as the dcssblk block device
and add a ->direct_access() method that is equivalent to
dcssblk_direct_access(). Once fs/dax.c has been converted to use
dax_operations the old dcssblk_direct_access() will be removed.
Reported-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Force writes to Storage Class Memory (SCM) to be in done in clusters.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Block device driver for Storage Class Memory (SCM). This driver
provides a block device interface for each available SCM increment.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Make use of def_bool and def_tristate where possible and add sensible
defaults to the config symbols where applicable. This shortens the
defconfig file by another ~40 lines.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
I compiled the kernel without deadline, and the dasd code exits the old
scheduler (CFQ), fails to load the new one (deadline), and then things just
hang - with one of these (sorry about the weird chars - I copy & pasted it
from a 3270 console):
dasd(eckd): 0.0.0151: 3390/0A(CU:3990/01) Cyl:3338 Head:15 Sec:224
------------ cut here ------------
Badness at kernel/mutex.c:134
Modules linked in: dasd_eckd_mod dasd_mod
CPU: 0 Not tainted 2.6.25-rc3 #9
Process exe (pid: 538, task: 000000000d172000, ksp: 000000000d21ef88)
Krnl PSW : 0404000180000000 000000000022fb5c (mutex_lock_nested+0x2a4/0x2cc)
R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0 EA:3
Krnl GPRS: 0000000000024218 000000000076fc78 0000000000000000 000000000000000f
000000000022f92e 0000000000449898 000000000f921c00 000003e000162590
00000000001539c4 000000000d172000 070000007fffffff 000000000d21f400
000000000f8f2560 00000000002413f8 000000000022fb44 000000000d21f400
Krnl Code: 000000000022fb50: bf2f1000 icm %r2,15,0(%r1)
000000000022fb54: a774fef6 brc 7,22f940
000000000022fb58: a7f40001 brc 15,22fb5a
>000000000022fb5c: a7f4fef2 brc 15,22f940
000000000022fb60: c0e5fffa112a brasl %r14,171db4
000000000022fb66: 1222 ltr %r2,%r2
000000000022fb68: a784fedb brc 8,22f91e
000000000022fb6c: c010002a0086 larl %r1,76fc78
Call Trace:
(<000000000022f92e> mutex_lock_nested+0x76/0x2cc)
<00000000001539c4> elevator_exit+0x38/0x80
<0000000000156ffe> blk_cleanup_queue+0x62/0x7c
<000003e0001d5414> dasd_change_state+0xe0/0x8ec
<000003e0001d5cae> dasd_set_target_state+0x8e/0x9c
<000003e0001d5f74> dasd_generic_set_online+0x160/0x284
<000003e00011e83a> dasd_eckd_set_online+0x2e/0x40
<0000000000199bf4> ccw_device_set_online+0x170/0x2c0
<0000000000199d9e> online_store_recog_and_online+0x5a/0x14c
<000000000019a08a> online_store+0xbe/0x2ec
<000000000018456c> dev_attr_store+0x38/0x58
<000000000010efbc> sysfs_write_file+0x130/0x190
<00000000000af582> vfs_write+0xb2/0x160
<00000000000afc7c> sys_write+0x54/0x9c
<0000000000025e16> sys32_write+0x2e/0x50
<0000000000024218> sysc_noemu+0x10/0x16
<0000000077e82bd2> 0x77e82bd2
Set elevator pointer to NULL in order to avoid double elevator_exit
calls when elevator_init call for deadline iosched fails.
Also make sure the dasd device driver depends on IOSCHED_DEADLINE so
the default IO scheduler of the dasd driver is present.
Signed-off-by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Disband drivers/s390/Kconfig, use the common Kconfig files. The s390
specific config options from drivers/s390/Kconfig are moved to the
respective common Kconfig files.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The DASD extended error reporting is a facility that allows to get detailed
information about certain problems in the DASD I/O. This information can be
used to implement fail-over applications that can recover these problems.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The dasd diag discipline has been tested on 64 bit and is no longer
experimental.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
dasd_cmd just implements three ioctls which are wrappers around functionality
in the core kernel or other modules. When merging those into dasd_mod they
just add 22 lines of code which is far less than the amount of code removed in
the last two patches, and which doesn't spill into another 4k pages when build
modular, while removing a 128lines module.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Revert dasd eer module until we have a common understanding of how the
interface should be.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The DASD extended error reporting is a facility that allows to get detailed
information about certain problems in the DASD I/O. This information can be
used to implement fail-over applications that can recover these problems.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Sanitize some s390 Kconfig options. We have ARCH_S390, ARCH_S390X,
ARCH_S390_31, 64BIT, S390_SUPPORT and COMPAT. Replace these 6 options by
S390, 64BIT and COMPAT.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add support for diag 250 access to dasd devices for 64 bit kernels. In
addition fix detach/attach for diag disks. The VM control block needs to get
recreated by a call to mdsk_init_io.
Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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!
