[dm-devel] [PATCH 2/5] dm-rq: handle dispatch exception in dm_dispatch_clone_request()
Ming Lei
ming.lei at redhat.com
Mon Jan 22 03:35:47 UTC 2018
So we can clean up map_request() a bit, no functional change.
Cc: Mike Snitzer <snitzer at redhat.com>
Cc: Laurence Oberman <loberman at redhat.com>
Cc: Bart Van Assche <bart.vanassche at sandisk.com>
Signed-off-by: Ming Lei <ming.lei at redhat.com>
---
drivers/md/dm-rq.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index e0bb56723b9b..1408e6664c16 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -12,6 +12,9 @@
#define DM_MSG_PREFIX "core-rq"
+#define dispatch_busy(r) \
+ (((r) == BLK_STS_RESOURCE) || ((r) == BLK_STS_DEV_RESOURCE))
+
#define DM_MQ_NR_HW_QUEUES 1
#define DM_MQ_QUEUE_DEPTH 2048
static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
@@ -399,7 +402,8 @@ static void end_clone_request(struct request *clone, blk_status_t error)
dm_complete_request(tio->orig, error);
}
-static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq)
+static blk_status_t dm_dispatch_clone_request(struct dm_rq_target_io *tio,
+ struct request *clone, struct request *rq)
{
blk_status_t r;
@@ -408,9 +412,17 @@ static blk_status_t dm_dispatch_clone_request(struct request *clone, struct requ
clone->start_time = jiffies;
r = blk_insert_cloned_request(clone->q, clone);
- if (r != BLK_STS_OK && r != BLK_STS_RESOURCE)
+ if (dispatch_busy(r)) {
+ blk_rq_unprep_clone(clone);
+ tio->ti->type->release_clone_rq(clone);
+ tio->clone = NULL;
+ } else if (r != BLK_STS_OK) {
/* must complete clone in terms of original request */
dm_complete_request(rq, r);
+
+ /* we handled the failure, so return OK */
+ r = BLK_STS_OK;
+ }
return r;
}
@@ -499,11 +511,8 @@ static int map_request(struct dm_rq_target_io *tio)
/* The target has remapped the I/O so dispatch it */
trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
blk_rq_pos(rq));
- ret = dm_dispatch_clone_request(clone, rq);
- if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
- blk_rq_unprep_clone(clone);
- tio->ti->type->release_clone_rq(clone);
- tio->clone = NULL;
+ ret = dm_dispatch_clone_request(tio, clone, rq);
+ if (dispatch_busy(ret)) {
if (!rq->q->mq_ops)
r = DM_MAPIO_DELAY_REQUEUE;
else
--
2.9.5
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