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| author | Mike Snitzer <snitzer@redhat.com> | 2018-01-12 19:53:40 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2018-01-29 13:44:54 -0500 |
| commit | ac514ffc968bf14649dd0e048447dc966ee49555 (patch) | |
| tree | 5f855e84e686deabbe559f2b7f4e440e5c8fd2c5 /drivers/md/dm-rq.c | |
| parent | 459b54019cfeb7330ed4863ad40f78489e0ff23d (diff) | |
| download | lwn-ac514ffc968bf14649dd0e048447dc966ee49555.tar.gz lwn-ac514ffc968bf14649dd0e048447dc966ee49555.zip | |
dm mpath: delay the retry of a request if the target responded as busy
Add DM_ENDIO_DELAY_REQUEUE to allow request-based multipath's
multipath_end_io() to instruct dm-rq.c:dm_done() to delay a requeue.
This is beneficial to do if BLK_STS_RESOURCE is returned from the target
(because target is busy).
Relative to blk-mq: kick the hw queues via blk_mq_requeue_work(),
indirectly from dm-rq.c:__dm_mq_kick_requeue_list(), after a delay.
For old .request_fn: use blk_delay_queue().
bio-based multipath doesn't have feature parity with request-based for
retryable error requeues; that is something that'll need fixing in the
future.
Suggested-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Bart Van Assche <bart.vanassche@wdc.com>
[as interpreted from Bart's "... patch looks fine to me."]
Diffstat (limited to 'drivers/md/dm-rq.c')
| -rw-r--r-- | drivers/md/dm-rq.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 9d32f25489c2..b78ff6921cfb 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -315,6 +315,10 @@ static void dm_done(struct request *clone, blk_status_t error, bool mapped) /* The target wants to requeue the I/O */ dm_requeue_original_request(tio, false); break; + case DM_ENDIO_DELAY_REQUEUE: + /* The target wants to requeue the I/O after a delay */ + dm_requeue_original_request(tio, true); + break; default: DMWARN("unimplemented target endio return value: %d", r); BUG(); |