blk-mq: Allow requests to never expire

Some types of requests may be started that are not gauranteed to ever
complete. This adds a request flag that a driver can use so mark the
request as such.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

2 files changed, 6 insertions, 1 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 261ccd89e15d..78324a2f0e10 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -619,7 +619,7 @@ void blk_mq_rq_timed_out(struct request *req, bool reserved)
                 break;
         }
 }
-                
+
 static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
                 struct request *rq, void *priv, bool reserved)
 {
@@ -627,6 +627,8 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
 
         if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
                 return;
+        if (rq->cmd_flags & REQ_NO_TIMEOUT)
+                return;
 
         if (time_after_eq(jiffies, rq->deadline)) {
                 if (!blk_mark_rq_complete(rq))
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 56c025894cdf..246dfb16c3d9 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -190,6 +190,9 @@ void blk_add_timer(struct request *req)
         struct request_queue *q = req->q;
         unsigned long expiry;
 
+        if (req->cmd_flags & REQ_NO_TIMEOUT)
+                return;
+
         /* blk-mq has its own handler, so we don't need ->rq_timed_out_fn */
         if (!q->mq_ops && !q->rq_timed_out_fn)
                 return;