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authoryangerkun <yangerkun@huawei.com>2020-09-05 19:25:56 +0800
committerJens Axboe <axboe@kernel.dk>2020-09-29 08:10:17 -0600
commit632bfb6323799c087fcb4108dfe59518609667a7 (patch)
tree82a008b131427f22482b359a62434ebc77f8421d /block
parent3aab91774bbd8e571cfaddaf839aafd07718333c (diff)
blk-mq: call commit_rqs while list empty but error happen
Blk-mq should call commit_rqs once 'bd.last != true' and no more request will come(so virtscsi can kick the virtqueue, e.g.). We already do that in 'blk_mq_dispatch_rq_list/blk_mq_try_issue_list_directly' while list not empty and 'queued > 0'. However, we can seen the same scene once the last request in list call queue_rq and return error like BLK_STS_IOERR which will not requeue the request, and lead that list empty but need call commit_rqs too(Or the request for virtscsi will stay timeout until other request kick virtqueue). We found this problem by do fsstress test with offline/online virtscsi device repeat quickly. Fixes: d666ba98f849 ("blk-mq: add mq_ops->commit_rqs()") Reported-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: yangerkun <yangerkun@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index b3d2785eefe9..cdced4aca2e8 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1412,6 +1412,11 @@ out:
hctx->dispatched[queued_to_index(queued)]++;
+ /* If we didn't flush the entire list, we could have told the driver
+ * there was more coming, but that turned out to be a lie.
+ */
+ if ((!list_empty(list) || errors) && q->mq_ops->commit_rqs && queued)
+ q->mq_ops->commit_rqs(hctx);
/*
* Any items that need requeuing? Stuff them into hctx->dispatch,
* that is where we will continue on next queue run.
@@ -1425,14 +1430,6 @@ out:
blk_mq_release_budgets(q, nr_budgets);
- /*
- * If we didn't flush the entire list, we could have told
- * the driver there was more coming, but that turned out to
- * be a lie.
- */
- if (q->mq_ops->commit_rqs && queued)
- q->mq_ops->commit_rqs(hctx);
-
spin_lock(&hctx->lock);
list_splice_tail_init(list, &hctx->dispatch);
spin_unlock(&hctx->lock);
@@ -2079,6 +2076,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
struct list_head *list)
{
int queued = 0;
+ int errors = 0;
while (!list_empty(list)) {
blk_status_t ret;
@@ -2095,6 +2093,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
break;
}
blk_mq_end_request(rq, ret);
+ errors++;
} else
queued++;
}
@@ -2104,7 +2103,8 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
* the driver there was more coming, but that turned out to
* be a lie.
*/
- if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs && queued)
+ if ((!list_empty(list) || errors) &&
+ hctx->queue->mq_ops->commit_rqs && queued)
hctx->queue->mq_ops->commit_rqs(hctx);
}