block: add a bio_queue_enter helper

Add a little helper that passes the right nowait flag to blk_queue_enter
based on the bio flag, and terminates the bio with the right error code
if entering the queue fails.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-core.c b/block/blk-core.c
index 81a291085c6ca2d22f399c835493379b68365b7b..7f11560bfddbb2f74711a73ac926ae9882035119 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -440,6 +440,23 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
        }
 }
 
+static inline int bio_queue_enter(struct bio *bio)
+{
+       struct request_queue *q = bio->bi_disk->queue;
+       bool nowait = bio->bi_opf & REQ_NOWAIT;
+       int ret;
+
+       ret = blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0);
+       if (unlikely(ret)) {
+               if (nowait && !blk_queue_dying(q))
+                       bio_wouldblock_error(bio);
+               else
+                       bio_io_error(bio);
+       }
+
+       return ret;
+}
+
 void blk_queue_exit(struct request_queue *q)
 {
        percpu_ref_put(&q->q_usage_counter);
@@ -1049,10 +1066,8 @@ blk_qc_t generic_make_request(struct bio *bio)
        current->bio_list = bio_list_on_stack;
        do {
                struct request_queue *q = bio->bi_disk->queue;
-               blk_mq_req_flags_t flags = bio->bi_opf & REQ_NOWAIT ?
-                       BLK_MQ_REQ_NOWAIT : 0;
 
-               if (likely(blk_queue_enter(q, flags) == 0)) {
+               if (likely(bio_queue_enter(bio) == 0)) {
                        struct bio_list lower, same;
 
                        /* Create a fresh bio_list for all subordinate requests */
@@ -1079,12 +1094,6 @@ blk_qc_t generic_make_request(struct bio *bio)
                        bio_list_merge(&bio_list_on_stack[0], &lower);
                        bio_list_merge(&bio_list_on_stack[0], &same);
                        bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
-               } else {
-                       if (unlikely(!blk_queue_dying(q) &&
-                                       (bio->bi_opf & REQ_NOWAIT)))
-                               bio_wouldblock_error(bio);
-                       else
-                               bio_io_error(bio);
                }
                bio = bio_list_pop(&bio_list_on_stack[0]);
        } while (bio);
@@ -1106,30 +1115,19 @@ EXPORT_SYMBOL(generic_make_request);
 blk_qc_t direct_make_request(struct bio *bio)
 {
        struct request_queue *q = bio->bi_disk->queue;
-       bool nowait = bio->bi_opf & REQ_NOWAIT;
        blk_qc_t ret;
 
-       if (WARN_ON_ONCE(q->make_request_fn))
-               goto io_error;
-       if (!generic_make_request_checks(bio))
+       if (WARN_ON_ONCE(q->make_request_fn)) {
+               bio_io_error(bio);
                return BLK_QC_T_NONE;
-
-       if (unlikely(blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0))) {
-               if (nowait && !blk_queue_dying(q))
-                       goto would_block;
-               goto io_error;
        }
-
+       if (!generic_make_request_checks(bio))
+               return BLK_QC_T_NONE;
+       if (unlikely(bio_queue_enter(bio)))
+               return BLK_QC_T_NONE;
        ret = blk_mq_make_request(q, bio);
        blk_queue_exit(q);
        return ret;
-
-would_block:
-       bio_wouldblock_error(bio);
-       return BLK_QC_T_NONE;
-io_error:
-       bio_io_error(bio);
-       return BLK_QC_T_NONE;
 }
 EXPORT_SYMBOL_GPL(direct_make_request);