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authorMing Lei <ming.lei@redhat.com>2020-07-01 21:58:57 +0800
committerJens Axboe <axboe@kernel.dk>2020-07-08 16:04:39 -0600
commit7bf137298cb73afdb8c5536e474f7ba71ab1c235 (patch)
tree5762e0620cc50f1e02b615170b62f2fa9202a863 /block
parent0e6e255e7a58cdf4ee4163f83deeb5ce4946051e (diff)
blk-mq: streamline handling of q->mq_ops->queue_rq result
Current handling of q->mq_ops->queue_rq result is a bit ugly: - two branches which needs to 'continue' have to check if the dispatch local list is empty, otherwise one bad request may be retrieved via 'rq = list_first_entry(list, struct request, queuelist);' - the branch of 'if (unlikely(ret != BLK_STS_OK))' isn't easy to follow, since it is actually one error branch. Streamline this handling, so the code becomes more readable, meantime potential kernel oops can be avoided in case that the last request in local dispatch list is failed. Fixes: fc17b6534eb8 ("blk-mq: switch ->queue_rq return value to blk_status_t") Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c24
1 files changed, 11 insertions, 13 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index abcf590f6238..89c83fa97ba0 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1387,30 +1387,28 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
if (nr_budgets)
nr_budgets--;
ret = q->mq_ops->queue_rq(hctx, &bd);
- if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
- blk_mq_handle_dev_resource(rq, list);
+ switch (ret) {
+ case BLK_STS_OK:
+ queued++;
break;
- } else if (ret == BLK_STS_ZONE_RESOURCE) {
+ case BLK_STS_RESOURCE:
+ case BLK_STS_DEV_RESOURCE:
+ blk_mq_handle_dev_resource(rq, list);
+ goto out;
+ case BLK_STS_ZONE_RESOURCE:
/*
* Move the request to zone_list and keep going through
* the dispatch list to find more requests the drive can
* accept.
*/
blk_mq_handle_zone_resource(rq, &zone_list);
- if (list_empty(list))
- break;
- continue;
- }
-
- if (unlikely(ret != BLK_STS_OK)) {
+ break;
+ default:
errors++;
blk_mq_end_request(rq, BLK_STS_IOERR);
- continue;
}
-
- queued++;
} while (!list_empty(list));
-
+out:
if (!list_empty(&zone_list))
list_splice_tail_init(&zone_list, list);