diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2021-02-10 15:26:23 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2021-02-11 09:45:28 -0500 |
| commit | a666e5c05e7c4aaabb2c5d58117b0946803d03d2 (patch) | |
| tree | 1a9dc24b70359cd4f268966d99763d79bea28926 /drivers/md/dm-core.h | |
| parent | e3290b9491ff5b7ee40f9e0a4c06821988a2a2bf (diff) | |
dm: fix deadlock when swapping to encrypted device
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 <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-core.h')
| -rw-r--r-- | drivers/md/dm-core.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index bf3e66f39a4a..5953ff2bd260 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -103,6 +103,10 @@ struct mapped_device { /* kobject and completion */ struct dm_kobject_holder kobj_holder; + int swap_bios; + struct semaphore swap_bios_semaphore; + struct mutex swap_bios_lock; + struct dm_stats stats; /* for blk-mq request-based DM support */ |