If a driver sets BLK_MQ_F_BLOCKING, it is allowed to block in its
->queue_rq() handler. For that case, blk-mq ensures that we always
calls it from a safe context.
Signed-off-by: Jens Axboe <axboe@xxxxxx>
---
block/blk-mq.c | 2 +-
include/linux/blk-mq.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index c29700010b5c..eae2f12f011f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -908,7 +908,7 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
!blk_mq_hw_queue_mapped(hctx)))
return;
- if (!async) {
+ if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
int cpu = get_cpu();
if (cpumask_test_cpu(cpu, hctx->cpumask)) {
__blk_mq_run_hw_queue(hctx);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index fbcfdf323243..5daa0ef756dd 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -155,6 +155,7 @@ enum {
BLK_MQ_F_TAG_SHARED = 1 << 1,
BLK_MQ_F_SG_MERGE = 1 << 2,
BLK_MQ_F_DEFER_ISSUE = 1 << 4,
+ BLK_MQ_F_BLOCKING = 1 << 5,
BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
BLK_MQ_F_ALLOC_POLICY_BITS = 1,
--
2.7.4
--
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