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-rw-r--r--block/blk-flush.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 4427896641ac..0d5a9c1da1fc 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -297,8 +297,14 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq)
if (fq->flush_pending_idx != fq->flush_running_idx || list_empty(pending))
return false;
- /* C2 and C3 */
+ /* C2 and C3
+ *
+ * For blk-mq + scheduling, we can risk having all driver tags
+ * assigned to empty flushes, and we deadlock if we are expecting
+ * other requests to make progress. Don't defer for that case.
+ */
if (!list_empty(&fq->flush_data_in_flight) &&
+ !(q->mq_ops && q->elevator) &&
time_before(jiffies,
fq->flush_pending_since + FLUSH_PENDING_TIMEOUT))
return false;
@@ -327,7 +333,6 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq)
blk_mq_tag_set_rq(hctx, first_rq->tag, flush_rq);
}
- flush_rq->cmd_type = REQ_TYPE_FS;
flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH;
flush_rq->rq_flags |= RQF_FLUSH_SEQ;
flush_rq->rq_disk = first_rq->rq_disk;
@@ -547,11 +552,10 @@ struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
if (!fq)
goto fail;
- if (q->mq_ops) {
+ if (q->mq_ops)
spin_lock_init(&fq->mq_flush_lock);
- rq_sz = round_up(rq_sz + cmd_size, cache_line_size());
- }
+ rq_sz = round_up(rq_sz + cmd_size, cache_line_size());
fq->flush_rq = kzalloc_node(rq_sz, GFP_KERNEL, node);
if (!fq->flush_rq)
goto fail_rq;