diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2015-05-27 15:25:27 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2015-05-27 17:37:23 -0400 |
| commit | 45714fbed4556149d7f1730f5bae74f81d5e2cd5 (patch) | |
| tree | 7bebdecc13511fc03de8b4d08e98d967c45d5d3b /drivers/md | |
| parent | 4c6dd53dd3674c310d7379c6b3273daa9fd95c79 (diff) | |
| download | linux-45714fbed4556149d7f1730f5bae74f81d5e2cd5.tar.bz2 | |
dm: requeue from blk-mq dm_mq_queue_rq() using BLK_MQ_RQ_QUEUE_BUSY
Use BLK_MQ_RQ_QUEUE_BUSY to requeue a blk-mq request directly from the
DM blk-mq device's .queue_rq. This cleans up the previous convoluted
handling of request requeueing that would return BLK_MQ_RQ_QUEUE_OK
(even though it wasn't) and then run blk_mq_requeue_request() followed
by blk_mq_kick_requeue_list().
Also, document that DM blk-mq ontop of old request_fn devices cannot
fail in clone_rq() since the clone request is preallocated as part of
the pdu.
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 1c62ed8d09f4..1badfb250a18 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2754,13 +2754,15 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, if (dm_table_get_type(map) == DM_TYPE_REQUEST_BASED) { /* clone request is allocated at the end of the pdu */ tio->clone = (void *)blk_mq_rq_to_pdu(rq) + sizeof(struct dm_rq_target_io); - if (!clone_rq(rq, md, tio, GFP_ATOMIC)) - return BLK_MQ_RQ_QUEUE_BUSY; + (void) clone_rq(rq, md, tio, GFP_ATOMIC); queue_kthread_work(&md->kworker, &tio->work); } else { /* Direct call is fine since .queue_rq allows allocations */ - if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) - dm_requeue_unmapped_original_request(md, rq); + if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) { + /* Undo dm_start_request() before requeuing */ + rq_completed(md, rq_data_dir(rq), false); + return BLK_MQ_RQ_QUEUE_BUSY; + } } return BLK_MQ_RQ_QUEUE_OK; |