block: add missing blk_queue_dead() checks

blk_insert_cloned_request(), blk_execute_rq_nowait() and
blk_flush_plug_list() either didn't check whether the queue was dead
or did it without holding queue_lock.  Update them so that dead state
is checked while holding queue_lock.

AFAICS, this plugs all holes (requeue doesn't matter as the request is
transitioning atomically from in_flight to queued).

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

2 files changed, 25 insertions, 2 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index c37e9e7c9d07..30add45a87ef 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1731,6 +1731,10 @@ int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
                 return -EIO;
 
         spin_lock_irqsave(q->queue_lock, flags);
+        if (unlikely(blk_queue_dead(q))) {
+                spin_unlock_irqrestore(q->queue_lock, flags);
+                return -ENODEV;
+        }
 
         /*
          * Submitting request must be dequeued before calling this function
@@ -2705,6 +2709,14 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth,
         trace_block_unplug(q, depth, !from_schedule);
 
         /*
+         * Don't mess with dead queue.
+         */
+        if (unlikely(blk_queue_dead(q))) {
+                spin_unlock(q->queue_lock);
+                return;
+        }
+
+        /*
          * If we are punting this to kblockd, then we can safely drop
          * the queue_lock before waking kblockd (which needs to take
          * this lock).
@@ -2780,6 +2792,15 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
                         depth = 0;
                         spin_lock(q->queue_lock);
                 }
+
+                /*
+                 * Short-circuit if @q is dead
+                 */
+                if (unlikely(blk_queue_dead(q))) {
+                        __blk_end_request_all(rq, -ENODEV);
+                        continue;
+                }
+
                 /*
                  * rq is already accounted, so use raw insert
                  */
diff --git a/block/blk-exec.c b/block/blk-exec.c
index 60532852b3ab..fb2cbd551621 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -50,7 +50,11 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
 {
         int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
 
+        WARN_ON(irqs_disabled());
+        spin_lock_irq(q->queue_lock);
+
         if (unlikely(blk_queue_dead(q))) {
+                spin_unlock_irq(q->queue_lock);
                 rq->errors = -ENXIO;
                 if (rq->end_io)
                         rq->end_io(rq, rq->errors);
@@ -59,8 +63,6 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
 
         rq->rq_disk = bd_disk;
         rq->end_io = done;
-        WARN_ON(irqs_disabled());
-        spin_lock_irq(q->queue_lock);
         __elv_add_request(q, rq, where);
         __blk_run_queue(q);
         /* the queue is stopped so it won't be run */