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author | Mikulas Patocka <mpatocka@redhat.com> | 2021-02-10 21:26:23 +0100 |
---|---|---|
committer | Mike Snitzer <snitzer@redhat.com> | 2021-02-11 15:45:28 +0100 |
commit | a666e5c05e7c4aaabb2c5d58117b0946803d03d2 (patch) | |
tree | 1a9dc24b70359cd4f268966d99763d79bea28926 /include | |
parent | dm: simplify target code conditional on CONFIG_BLK_DEV_ZONED (diff) | |
download | linux-a666e5c05e7c4aaabb2c5d58117b0946803d03d2.tar.xz linux-a666e5c05e7c4aaabb2c5d58117b0946803d03d2.zip |
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 'include')
-rw-r--r-- | include/linux/device-mapper.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index c98d847b0f0b..7f4ac87c0b32 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -343,6 +343,11 @@ struct dm_target { * whether or not its underlying devices have support. */ bool discards_supported:1; + + /* + * Set if we need to limit the number of in-flight bios when swapping. + */ + bool limit_swap_bios:1; }; void *dm_per_bio_data(struct bio *bio, size_t data_size); |