kernel.git/drivers/md/dm-core.h, branch linux-5.10.y

dm: rearrange core declarations for extended use from dm-zone.c

2025-08-28T14:22:57Z

commit e2118b3c3d94289852417f70ec128c25f4833aad upstream. Move the definitions of struct dm_target_io, struct dm_io and the bits of the flags field of struct mapped_device from dm.c to dm-core.h to make them usable from dm-zone.c. For the same reason, declare dec_pending() in dm-core.h after renaming it to dm_io_dec_pending(). And for symmetry of the function names, introduce the inline helper dm_io_inc_pending() instead of directly using atomic_inc() calls. Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Reviewed-by: Himanshu Madhani Signed-off-by: Mike Snitzer [Shivani: Modified to apply on 5.10.y] Signed-off-by: Shivani Agarwal Signed-off-by: Greg Kroah-Hartman

dm: limit the number of targets and parameter size area

2024-02-23T07:42:32Z

commit bd504bcfec41a503b32054da5472904b404341a4 upstream. The kvmalloc function fails with a warning if the size is larger than INT_MAX. The warning was triggered by a syscall testing robot. In order to avoid the warning, this commit limits the number of targets to 1048576 and the size of the parameter area to 1073741824. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: He Gao Signed-off-by: Greg Kroah-Hartman

dm: fix deadlock when swapping to encrypted device

2021-03-04T10:38:44Z

commit a666e5c05e7c4aaabb2c5d58117b0946803d03d2 upstream. The system would deadlock when swapping to a dm-crypt device. The reason is that for each incoming write bio, dm-crypt allocates memory that holds encrypted data. These excessive allocations exhaust all the memory and the result is either deadlock or OOM trigger. This patch limits the number of in-flight swap bios, so that the memory consumed by dm-crypt is limited. The limit is enforced if the target set the "limit_swap_bios" variable and if the bio has REQ_SWAP set. Non-swap bios are not affected becuase taking the semaphore would cause performance degradation. This is similar to request-based drivers - they will also block when the number of requests is over the limit. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm table: make 'struct dm_table' definition accessible to all of DM core

2020-09-29T20:33:07Z

Move 'struct dm_table' definition from dm-table.c to dm-core.h and update DM core to access its members directly. Helps optimize max_io_len() and other methods slightly. Signed-off-by: Mike Snitzer

dm: disable DISCARD if the underlying storage no longer supports it

2019-04-04T19:33:59Z

Storage devices which report supporting discard commands like WRITE_SAME_16 with unmap, but reject discard commands sent to the storage device. This is a clear storage firmware bug but it doesn't change the fact that should a program cause discards to be sent to a multipath device layered on this buggy storage, all paths can end up failed at the same time from the discards, causing possible I/O loss. The first discard to a path will fail with Illegal Request, Invalid field in cdb, e.g.: kernel: sd 8:0:8:19: [sdfn] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE kernel: sd 8:0:8:19: [sdfn] tag#0 Sense Key : Illegal Request [current] kernel: sd 8:0:8:19: [sdfn] tag#0 Add. Sense: Invalid field in cdb kernel: sd 8:0:8:19: [sdfn] tag#0 CDB: Write same(16) 93 08 00 00 00 00 00 a0 08 00 00 00 80 00 00 00 kernel: blk_update_request: critical target error, dev sdfn, sector 10487808 The SCSI layer converts this to the BLK_STS_TARGET error number, the sd device disables its support for discard on this path, and because of the BLK_STS_TARGET error multipath fails the discard without failing any path or retrying down a different path. But subsequent discards can cause path failures. Any discards sent to the path which already failed a discard ends up failing with EIO from blk_cloned_rq_check_limits with an "over max size limit" error since the discard limit was set to 0 by the sd driver for the path. As the error is EIO, this now fails the path and multipath tries to send the discard down the next path. This cycle continues as discards are sent until all paths fail. Fix this by training DM core to disable DISCARD if the underlying storage already did so. Also, fix branching in dm_done() and clone_endio() to reflect the mutually exclussive nature of the IO operations in question. Cc: stable@vger.kernel.org Reported-by: David Jeffery Signed-off-by: Mike Snitzer

dm: don't reuse bio for flushes

2018-12-19T16:13:34Z

DM currently has a statically allocated bio that it uses to issue empty flushes. It doesn't submit this bio, it just uses it for maintaining state while setting up clones. Multiple users can access this bio at the same time. This wasn't previously an issue, even if it was a bit iffy, but with the blkg associations it can become one. We setup the blkg association, then clone bio's and submit, then remove the blkg assocation again. But since we can have multiple tasks doing this at the same time, against multiple blkg's, then we can either lose references to a blkg, or put it twice. The latter causes complaints on the percpu ref being <= 0 when released, and can cause use-after-free as well. Ming reports that xfstest generic/475 triggers this: ------------[ cut here ]------------ percpu ref (blkg_release) <= 0 (0) after switching to atomic WARNING: CPU: 13 PID: 0 at lib/percpu-refcount.c:155 percpu_ref_switch_to_atomic_rcu+0x2c9/0x4a0 Switch to just using an on-stack bio for this, and get rid of the embedded bio. Fixes: 5cdf2e3fea5e ("blkcg: associate blkg when associating a device") Reported-by: Ming Lei Tested-by: Ming Lei Reviewed-by: Mike Snitzer Signed-off-by: Jens Axboe

dm: remove the pending IO accounting

2018-12-10T15:30:38Z

Remove the "pending" atomic counters, that duplicate block-core's in_flight counters, and update md_in_flight() to look at percpu in_flight counters. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Jens Axboe

dm: remove legacy request-based IO path

2018-10-11T15:36:09Z

dm supports both, and since we're killing off the legacy path in general, get rid of it in dm. Signed-off-by: Jens Axboe Signed-off-by: Mike Snitzer

dm: adjust structure members to improve alignment

2018-06-08T15:53:14Z

Eliminate most holes in DM data structures that were modified by commit 6f1c819c21 ("dm: convert to bioset_init()/mempool_init()"). Also prevent structure members from unnecessarily spanning cache lines. Signed-off-by: Mike Snitzer

dm: convert to bioset_init()/mempool_init()

2018-05-30T21:33:32Z

Convert dm to embedded bio sets. Acked-by: Mike Snitzer Signed-off-by: Kent Overstreet Signed-off-by: Jens Axboe