diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2021-02-10 15:26:23 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-04 10:26:51 +0100 |
| commit | 5233c47c8d468be88ae594d2fd19e89f321bf419 (patch) | |
| tree | cc37bc86efcb266a0d63fbd093135382e3f095a3 /include | |
| parent | fd3b7e07d3c148a910fddb94e83b6824f6aa8874 (diff) | |
dm: fix deadlock when swapping to encrypted device
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 <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 e4e1f5c1f492..a53d7d2c2d95 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -316,6 +316,11 @@ 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; }; /* Each target can link one of these into the table */ |