kernel/git/stable/linux.git/drivers/md/dm-cache-policy-smq.c, branch master

Merge tag 'for-7.2/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2026-06-16T07:50:54+00:00

Pull device mapper updates from Mikulas Patocka: - small cleanups in dm-vdo, dm-raid, dm-cache, dm-zoned-metadata - rework of dm-ima - introduce dm-inlinecrypt - fix wrong return value in dm-ioctl - fix rcu stall when polling * tag 'for-7.2/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm-zoned-metadata: Use strscpy() to copy device name dm cache: make smq background work limit configurable dm-inlinecrypt: add support for hardware-wrapped keys dm: limit target bio polling to one shot dm-ioctl: report an error if a device has no table dm: add documentation for dm-inlinecrypt target dm-inlinecrypt: add target for inline block device encryption block: export blk-crypto symbols required by dm-inlinecrypt dm-ima: use active table's size if available dm-ima: Fail more gracefully in dm_ima_measure_on_* dm-ima: Handle race between rename and table swap dm-ima: Fix issues with dm_ima_measure_on_device_rename dm-ima: remove new_map from dm_ima_measure_on_device_clear dm-ima: Fix UAF errors and measuring incorrect context dm-ima: don't copy the active table to the inactive table dm-ima: Remove status_flags from dm_ima_measure_on_table_load() dm-ima: remove broken last_target_measured logic dm-ima: remove dm_ima_reset_data() dm-raid: only requeue bios when dm is suspending dm vdo: use get_random_u32() where appropriate

dm cache: make smq background work limit configurable

2026-06-01T15:55:31+00:00

The maximum number of concurrent background work items (promotions, demotions, writebacks) in the SMQ policy was hardcoded to 4096, with a FIXME comment noting it should be made configurable. This value was originally tuned down from 10240 to balance memory overhead (~128 bytes per entry, ~512KB at 4096 entries) against I/O parallelism. However, different workloads and cache sizes may benefit from different limits: - Write-heavy workloads may need more writeback concurrency - Very large caches (10+ TB) may need more promotion slots - Memory-constrained systems may want a lower limit Make this configurable via the module parameter "smq_max_background_work" (defaulting to 4096 to preserve existing behaviour). Clamp the value to at least 1 to prevent setting 0, which would block all background work. The parameter only affects newly created cache devices; existing caches retain their value from creation time. Signed-off-by: Cao Guanghui Signed-off-by: Mikulas Patocka

dm cache policy smq: check allocation under invalidate lock

2026-06-01T15:30:24+00:00

commit 2d1f7b65f5de ("dm cache policy smq: fix missing locks in invalidating cache blocks") added mq->lock around the destructive part of smq_invalidate_mapping(), but left the e->allocated check outside the critical section. That leaves a check-then-act race. Two concurrent invalidators can both observe e->allocated as true before either of them takes mq->lock. The first invalidator that acquires the lock removes the entry from the queues and hash table and then calls free_entry(), which clears e->allocated and puts the entry back on the free list. The second invalidator can then acquire mq->lock and continue with the stale result of the unlocked check. This can corrupt the SMQ queues or hash table by deleting an entry that is no longer on those structures. It can also hit the allocation check in free_entry() when the same entry is freed again. Move the allocation check under mq->lock so the predicate and the destructive operations are serialized by the same lock. Fixes: 2d1f7b65f5de ("dm cache policy smq: fix missing locks in invalidating cache blocks") Signed-off-by: Guangshuo Li Signed-off-by: Mikulas Patocka

dm cache policy smq: fix missing locks in invalidating cache blocks

2026-03-02T15:49:46+00:00

In passthrough mode, the policy invalidate_mapping operation is called simultaneously from multiple workers, thus it should be protected by a lock. Otherwise, we might end up with data races on the allocated blocks counter, or even use-after-free issues with internal data structures when doing concurrent writes. Note that the existing FIXME in smq_invalidate_mapping() doesn't affect passthrough mode since migration tasks don't exist there, but would need attention if supporting fast device shrinking via suspend/resume without target reloading. Reproduce steps: 1. Create a cache device consisting of 1024 cache entries dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 131072 linear /dev/sdc 8192" dmsetup create corig --table "0 262144 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. Populate the cache, and record the number of cached blocks fio --name=populate --filename=/dev/mapper/cache --rw=randwrite --bs=4k \ --size=64m --direct=1 nr_cached=$(dmsetup status cache | awk '{split($7, a, "/"); print a[1]}') 3. Reload the cache into passthrough mode dmsetup suspend cache dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0" dmsetup resume cache 4. Write to the passthrough cache. By setting multiple jobs with I/O size equal to the cache block size, cache blocks are invalidated concurrently from different workers. fio --filename=/dev/mapper/cache --name=test --rw=randwrite --bs=64k \ --direct=1 --numjobs=2 --randrepeat=0 --size=64m 5. Check if demoted matches cached block count. These numbers should match but may differ due to the data race. nr_demoted=$(dmsetup status cache | awk '{print $12}') echo "$nr_cached, $nr_demoted" Fixes: b29d4986d0da ("dm cache: significant rework to leverage dm-bio-prison-v2") Signed-off-by: Ming-Hung Tsai Signed-off-by: Mikulas Patocka

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

dm: use vmalloc_array() to simplify code

2025-08-19T09:12:50+00:00

Remove array_size() calls and replace vmalloc() with vmalloc_array() to simplify the code. Signed-off-by: Qianfeng Rong Signed-off-by: Mikulas Patocka

dm: update relevant MODULE_AUTHOR entries to latest dm-devel mailing list

2024-02-20T19:22:55+00:00

Signed-off-by: Mike Snitzer

dm cache policy smq: ensure IO doesn't prevent cleaner policy progress

2023-07-25T15:55:50+00:00

When using the cleaner policy to decommission the cache, there is never any writeback started from the cache as it is constantly delayed due to normal I/O keeping the device busy. Meaning @idle=false was always being passed to clean_target_met() Fix this by adding a specific 'cleaner' flag that is set when the cleaner policy is configured. This flag serves to always allow the cleaner's writeback work to be queued until the cache is decommissioned (even if the cache isn't idle). Reported-by: David Jeffery Fixes: b29d4986d0da ("dm cache: significant rework to leverage dm-bio-prison-v2") Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm: add missing empty lines

2023-02-14T19:23:06+00:00

Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer