linux.git/drivers/md/dm.c, branch v4.4

dm: do not reuse dm_blk_ioctl block_device input as local variable

2015-11-17T19:18:49+00:00

(Ab)using the @bdev passed to dm_blk_ioctl() opens the potential for
targets' .prepare_ioctl to fail if they go on to check the bdev for
!NULL.

Fixes: e56f81e0b01e ("dm: refactor ioctl handling")
Reported-by: Junichi Nomura 
Signed-off-by: Mike Snitzer

dm: fix ioctl retry termination with signal

2015-11-17T19:04:32+00:00

dm-mpath retries ioctl, when no path is readily available and the device
is configured to queue I/O in such a case. If you want to stop the retry
before multipathd decides to turn off queueing mode, you could send
signal for the process to exit from the loop.

However the check of fatal signal has not carried along when commit
6c182cd88d17 ("dm mpath: fix ioctl deadlock when no paths") moved the
loop from dm-mpath to dm core. As a result, we can't terminate such
a process in the retry loop.

Easy reproducer of the situation is:

  # dmsetup create mp --table '0 1024 multipath 0 0 0 0'
  # dmsetup message mp 0 'queue_if_no_path'
  # sg_inq /dev/mapper/mp

then you should be able to terminate sg_inq by pressing Ctrl+C.

Fixes: 6c182cd88d17 ("dm mpath: fix ioctl deadlock when no paths")
Signed-off-by: Jun'ichi Nomura 
Cc: Hannes Reinecke 
Cc: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Cc: stable@vger.kernel.org

block: change ->make_request_fn() and users to return a queue cookie

2015-11-07T17:40:46+00:00

No functional changes in this patch, but it prepares us for returning
a more useful cookie related to the IO that was queued up.

Signed-off-by: Jens Axboe 
Acked-by: Christoph Hellwig 
Acked-by: Keith Busch

Merge tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2015-11-05T05:19:53+00:00

Pull device mapper updates from Mike Snitzer:
 "Smaller set of DM changes for this merge.  I've based these changes on
  Jens' for-4.4/reservations branch because the associated DM changes
  required it.

   - Revert a dm-multipath change that caused a regression for
     unprivledged users (e.g. kvm guests) that issued ioctls when a
     multipath device had no available paths.

   - Include Christoph's refactoring of DM's ioctl handling and add
     support for passing through persistent reservations with DM
     multipath.

   - All other changes are very simple cleanups"

* tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm switch: simplify conditional in alloc_region_table()
  dm delay: document that offsets are specified in sectors
  dm delay: capitalize the start of an delay_ctr() error message
  dm delay: Use DM_MAPIO macros instead of open-coded equivalents
  dm linear: remove redundant target name from error messages
  dm persistent data: eliminate unnecessary return values
  dm: eliminate unused "bioset" process for each bio-based DM device
  dm: convert ffs to __ffs
  dm: drop NULL test before kmem_cache_destroy() and mempool_destroy()
  dm: add support for passing through persistent reservations
  dm: refactor ioctl handling
  Revert "dm mpath: fix stalls when handling invalid ioctls"
  dm: initialize non-blk-mq queue data before queue is used

Merge branch 'for-4.4/integrity' of git://git.kernel.dk/linux-block

2015-11-05T04:51:48+00:00

Pull block integrity updates from Jens Axboe:
 ""This is the joint work of Dan and Martin, cleaning up and improving
  the support for block data integrity"

* 'for-4.4/integrity' of git://git.kernel.dk/linux-block:
  block, libnvdimm, nvme: provide a built-in blk_integrity nop profile
  block: blk_flush_integrity() for bio-based drivers
  block: move blk_integrity to request_queue
  block: generic request_queue reference counting
  nvme: suspend i/o during runtime blk_integrity_unregister
  md: suspend i/o during runtime blk_integrity_unregister
  md, dm, scsi, nvme, libnvdimm: drop blk_integrity_unregister() at shutdown
  block: Inline blk_integrity in struct gendisk
  block: Export integrity data interval size in sysfs
  block: Reduce the size of struct blk_integrity
  block: Consolidate static integrity profile properties
  block: Move integrity kobject to struct gendisk

dm: eliminate unused "bioset" process for each bio-based DM device

2015-10-31T23:06:02+00:00

Commit 54efd50bfd873e2dbf784e0b21a8027ba4299a3e ("block: make
generic_make_request handle arbitrarily sized bios") makes it possible
for block devices to process large bios.  In doing so that commit
allocates a new queue->bio_split bioset for each block device, this
bioset is used for allocating bios when the driver needs to split large
bios.

Each bioset allocates a workqueue process, thus the above commit
increases the number of processes allocated per block device.

DM doesn't need the queue->bio_split bioset, thus we can deallocate it.
This reduces the number of allocated processes per bio-based DM device
from 3 to 2.  Also remove the call to blk_queue_split(), it is not
needed because DM does its own splitting.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm: drop NULL test before kmem_cache_destroy() and mempool_destroy()

2015-10-31T23:06:00+00:00

Remove DM's unneeded NULL tests before calling these destroy functions,
now that they check for NULL, thanks to these v4.3 commits:
3942d2991 ("mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()")
4e3ca3e03 ("mm/mempool: allow NULL `pool' pointer in mempool_destroy()")

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// 
@@ expression x; @@
-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Mike Snitzer

dm: add support for passing through persistent reservations

2015-10-31T23:05:59+00:00

This adds support to pass through persistent reservation requests
similar to the existing ioctl handling, and with the same limitations,
e.g. devices may only have a single target attached.

This is mostly intended for multipathing.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Mike Snitzer

dm: refactor ioctl handling

2015-10-31T23:05:59+00:00

This moves the call to blkdev_ioctl and the argument checking to DM core
code, and only leaves a callout to find the block device to operate on
in the targets.  This simplifies the code and allows us to pass through
ioctl-like command using other methods in the next patch.

Also split out a helper around calling the prepare_ioctl method that
will be reused for persistent reservation handling.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Mike Snitzer

dm: initialize non-blk-mq queue data before queue is used

2015-10-30T02:09:40+00:00

Commit bfebd1cdb497a57757c83f5fbf1a29931591e2a4 ("dm: add full blk-mq
support to request-based DM") moves the initialization of the fields
backing_dev_info.congested_fn, backing_dev_info.congested_data and
queuedata from the function dm_init_md_queue (that is called when the
device is created) to dm_init_old_md_queue (that is called after the
device type is determined).

There is no locking when accessing these variables, thus it is possible
for other parts of the kernel to briefly see this data in a transient
state (e.g. queue->backing_dev_info.congested_fn initialized and
md->queue->backing_dev_info.congested_data uninitialized, resulting in
passing an incorrect parameter to the function dm_any_congested).

This queue data is left initialized for blk-mq devices even though they
that don't use it.

Fixes: bfebd1cdb497 ("dm: add full blk-mq support to request-based DM")
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Cc: stable@vger.kernel.org # v4.1+