linux-toradex.git/drivers/md/dm-table.c, branch v5.3.2

dm table: fix invalid memory accesses with too high sector number

2019-08-23T14:11:42+00:00

If the sector number is too high, dm_table_find_target() should return a
pointer to a zeroed dm_target structure (the caller should test it with
dm_target_is_valid).

However, for some table sizes, the code in dm_table_find_target() that
performs btree lookup will access out of bound memory structures.

Fix this bug by testing the sector number at the beginning of
dm_table_find_target(). Also, add an "inline" keyword to the function
dm_table_get_size() because this is a hot path.

Fixes: 512875bd9661 ("dm: table detect io beyond device")
Cc: stable@vger.kernel.org
Reported-by: Zhang Tao 
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm table: fix various whitespace issues with recent DAX code

2019-07-30T22:59:24+00:00

Also, rename device_synchronous to device_dax_synchronous.

Signed-off-by: Mike Snitzer

dm table: fix dax_dev NULL dereference in device_synchronous()

2019-07-30T22:58:54+00:00

If a device doesn't support DAX its 'dax_dev' is NULL.  Fix
device_synchronous() to first check if dax_dev is NULL before
dereferencing it.

Fixes: 2e9ee0955d3c ("dm: enable synchronous dax")
Reported-by: jencce.kernel@gmail.com
Signed-off-by: Pankaj Gupta 
Acked-by: Dan Williams 
Signed-off-by: Mike Snitzer

Merge tag 'libnvdimm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2019-07-18T17:52:08+00:00

Pull libnvdimm updates from Dan Williams:
 "Primarily just the virtio_pmem driver:

   - virtio_pmem

     The new virtio_pmem facility introduces a paravirtualized
     persistent memory device that allows a guest VM to use DAX
     mechanisms to access a host-file with host-page-cache. It arranges
     for MAP_SYNC to be disabled and instead triggers a host fsync()
     when a 'write-cache flush' command is sent to the virtual disk
     device.

   - Miscellaneous small fixups"

* tag 'libnvdimm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  virtio_pmem: fix sparse warning
  xfs: disable map_sync for async flush
  ext4: disable map_sync for async flush
  dax: check synchronous mapping is supported
  dm: enable synchronous dax
  libnvdimm: add dax_dev sync flag
  virtio-pmem: Add virtio pmem driver
  libnvdimm: nd_region flush callback support
  libnvdimm, namespace: Drop uuid_t implementation detail

dm: enable synchronous dax

2019-07-05T22:19:10+00:00

This patch sets dax device 'DAXDEV_SYNC' flag if all the target
devices of device mapper support synchrononous DAX. If device
mapper consists of both synchronous and asynchronous dax devices,
we don't set 'DAXDEV_SYNC' flag.

'dm_table_supports_dax' is refactored to pass 'iterate_devices_fn'
as argument so that the callers can pass the appropriate functions.

Suggested-by: Mike Snitzer 
Signed-off-by: Pankaj Gupta 
Reviewed-by: Mike Snitzer 
Signed-off-by: Dan Williams

dm table: don't copy from a NULL pointer in realloc_argv()

2019-06-25T18:09:13+00:00

For the first call to realloc_argv() in dm_split_args(), old_argv is
NULL and size is zero. Then memcpy is called, with the NULL old_argv
as the source argument and a zero size argument. AFAIK, this is
undefined behavior and generates the following warning when compiled
with UBSAN on ppc64le:

In file included from ./arch/powerpc/include/asm/paca.h:19,
                 from ./arch/powerpc/include/asm/current.h:16,
                 from ./include/linux/sched.h:12,
                 from ./include/linux/kthread.h:6,
                 from drivers/md/dm-core.h:12,
                 from drivers/md/dm-table.c:8:
In function 'memcpy',
    inlined from 'realloc_argv' at drivers/md/dm-table.c:565:3,
    inlined from 'dm_split_args' at drivers/md/dm-table.c:588:9:
./include/linux/string.h:345:9: error: argument 2 null where non-null expected [-Werror=nonnull]
  return __builtin_memcpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/md/dm-table.c: In function 'dm_split_args':
./include/linux/string.h:345:9: note: in a call to built-in function '__builtin_memcpy'

Signed-off-by: Jerome Marchand 
Signed-off-by: Mike Snitzer

dax: Arrange for dax_supported check to span multiple devices

2019-05-20T22:02:08+00:00

Pankaj reports that starting with commit ad428cdb525a "dax: Check the
end of the block-device capacity with dax_direct_access()" device-mapper
no longer allows dax operation. This results from the stricter checks in
__bdev_dax_supported() that validate that the start and end of a
block-device map to the same 'pagemap' instance.

Teach the dax-core and device-mapper to validate the 'pagemap' on a
per-target basis. This is accomplished by refactoring the
bdev_dax_supported() internals into generic_fsdax_supported() which
takes a sector range to validate. Consequently generic_fsdax_supported()
is suitable to be used in a device-mapper ->iterate_devices() callback.
A new ->dax_supported() operation is added to allow composite devices to
split and route upper-level bdev_dax_supported() requests.

Fixes: ad428cdb525a ("dax: Check the end of the block-device...")
Cc: 
Cc: Ira Weiny 
Cc: Dave Jiang 
Cc: Keith Busch 
Cc: Matthew Wilcox 
Cc: Vishal Verma 
Cc: Heiko Carstens 
Cc: Martin Schwidefsky 
Reviewed-by: Jan Kara 
Reported-by: Pankaj Gupta 
Reviewed-by: Pankaj Gupta 
Tested-by: Pankaj Gupta 
Tested-by: Vaibhav Jain 
Reviewed-by: Mike Snitzer 
Signed-off-by: Dan Williams

dm table: propagate BDI_CAP_STABLE_WRITES to fix sporadic checksum errors

2019-04-01T20:26:02+00:00

Some devices don't use blk_integrity but still want stable pages
because they do their own checksumming.  Examples include rbd and iSCSI
when data digests are negotiated.  Stacking DM (and thus LVM) on top of
these devices results in sporadic checksum errors.

Set BDI_CAP_STABLE_WRITES if any underlying device has it set.

Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov 
Signed-off-by: Mike Snitzer

block: kill QUEUE_FLAG_NO_SG_MERGE

2019-02-15T15:40:12+00:00

Since bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting"),
physical segment number is mainly figured out in blk_queue_split() for
fast path, and the flag of BIO_SEG_VALID is set there too.

Now only blk_recount_segments() and blk_recalc_rq_segments() use this
flag.

Basically blk_recount_segments() is bypassed in fast path given BIO_SEG_VALID
is set in blk_queue_split().

For another user of blk_recalc_rq_segments():

- run in partial completion branch of blk_update_request, which is an unusual case

- run in blk_cloned_rq_check_limits(), still not a big problem if the flag is killed
since dm-rq is the only user.

Multi-page bvec is enabled now, not doing S/G merging is rather pointless with the
current setup of the I/O path, as it isn't going to save you a significant amount
of cycles.

Reviewed-by: Christoph Hellwig 
Reviewed-by: Omar Sandoval 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

dm: do not allow readahead to limit IO size

2018-12-18T19:23:41+00:00

Update DM to set the bdi's io_pages.  This fixes reads to be capped at
the device's max request size (even if user's read IO exceeds the
established readahead setting).

Fixes: 9491ae4a ("mm: don't cap request size based on read-ahead setting")
Cc: stable@vger.kernel.org
Reviewed-by: Jens Axboe 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Mike Snitzer