PM / Domains: Allow holes in genpd_data.domains array

[cascardo/linux.git] / block / blk-mq.c

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 576e711..e931a0e 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -672,7 +672,20 @@ static void blk_mq_timeout_work(struct work_struct *work)
        };
        int i;
 
-       if (blk_queue_enter(q, true))
+       /* A deadlock might occur if a request is stuck requiring a
+        * timeout at the same time a queue freeze is waiting
+        * completion, since the timeout code would not be able to
+        * acquire the queue reference here.
+        *
+        * That's why we don't use blk_queue_enter here; instead, we use
+        * percpu_ref_tryget directly, because we need to be able to
+        * obtain a reference even in the short window between the queue
+        * starting to freeze, by dropping the first reference in
+        * blk_mq_freeze_queue_start, and the moment the last request is
+        * consumed, marked by the instant q_usage_counter reaches
+        * zero.
+        */
+       if (!percpu_ref_tryget(&q->q_usage_counter))
                return;
 
        blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data);
@@ -1221,7 +1234,7 @@ static struct request *blk_mq_map_request(struct request_queue *q,
        ctx = blk_mq_get_ctx(q);
        hctx = q->mq_ops->map_queue(q, ctx->cpu);
 
-       if (rw_is_sync(bio_op(bio), bio->bi_rw))
+       if (rw_is_sync(bio_op(bio), bio->bi_opf))
                op_flags |= REQ_SYNC;
 
        trace_block_getrq(q, bio, op);
@@ -1289,8 +1302,8 @@ static int blk_mq_direct_issue_request(struct request *rq, blk_qc_t *cookie)
  */
 static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 {
-       const int is_sync = rw_is_sync(bio_op(bio), bio->bi_rw);
-       const int is_flush_fua = bio->bi_rw & (REQ_PREFLUSH | REQ_FUA);
+       const int is_sync = rw_is_sync(bio_op(bio), bio->bi_opf);
+       const int is_flush_fua = bio->bi_opf & (REQ_PREFLUSH | REQ_FUA);
        struct blk_map_ctx data;
        struct request *rq;
        unsigned int request_count = 0;
@@ -1383,8 +1396,8 @@ done:
  */
 static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
 {
-       const int is_sync = rw_is_sync(bio_op(bio), bio->bi_rw);
-       const int is_flush_fua = bio->bi_rw & (REQ_PREFLUSH | REQ_FUA);
+       const int is_sync = rw_is_sync(bio_op(bio), bio->bi_opf);
+       const int is_flush_fua = bio->bi_opf & (REQ_PREFLUSH | REQ_FUA);
        struct blk_plug *plug;
        unsigned int request_count = 0;
        struct blk_map_ctx data;