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| author | Mike Christie <mchristi@redhat.com> | 2017-11-28 12:40:33 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-12 12:32:21 +0200 |
| commit | bc166ca4234c241ae28b13bac8583d04bcdf9a9e (patch) | |
| tree | 605ed77e26dfcdf42ab7d0ede843feaba8361739 /drivers/target | |
| parent | 6a88a999c45db9500ab16656a9a15fa601403e17 (diff) | |
| download | linux-stable-bc166ca4234c241ae28b13bac8583d04bcdf9a9e.tar.gz linux-stable-bc166ca4234c241ae28b13bac8583d04bcdf9a9e.tar.bz2 linux-stable-bc166ca4234c241ae28b13bac8583d04bcdf9a9e.zip | |
tcmu: release blocks for partially setup cmds
[ Upstream commit 810b8153c4243d2012a6ec002ddd3bbc9a9ae8c2 ]
If we cannot setup a cmd because we run out of ring space
or global pages release the blocks before sleeping. This
prevents a deadlock where dev0 has waiting_blocks set and
needs N blocks, but dev1 to devX have each allocated N / X blocks
and also hit the global block limit so they went to sleep.
find_free_blocks is not able to take the sleeping dev's
blocks becaause their waiting_blocks is set and even
if it was not the block returned by find_last_bit could equal
dbi_max. The latter will probably never happen because
DATA_BLOCK_BITS is so high but in the next patches
DATA_BLOCK_BITS and TCMU_GLOBAL_MAX_BLOCKS will be settable so
it might be lower and could happen.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/target')
| -rw-r--r-- | drivers/target/target_core_user.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 942d094269fb..c4a5fb6f038f 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -796,6 +796,13 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) int ret; DEFINE_WAIT(__wait); + /* + * Don't leave commands partially setup because the unmap + * thread might need the blocks to make forward progress. + */ + tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cur); + tcmu_cmd_reset_dbi_cur(tcmu_cmd); + prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE); pr_debug("sleeping for ring space\n"); |