blk-mq: move the call to blk_queue_enter_live out of blk_mq_get_request

Move the blk_queue_enter_live calls into the callers, where they can
successively be cleaned up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4f8adef..b7e0667 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -342,8 +342,6 @@ static struct request *blk_mq_get_request(struct request_queue *q,
        bool clear_ctx_on_error = false;
        u64 alloc_time_ns = 0;
 
-       blk_queue_enter_live(q);
-
        /* alloc_time includes depth and tag waits */
        if (blk_queue_rq_alloc_time(q))
                alloc_time_ns = ktime_get_ns();
@@ -379,7 +377,6 @@ static struct request *blk_mq_get_request(struct request_queue *q,
        if (tag == BLK_MQ_TAG_FAIL) {
                if (clear_ctx_on_error)
                        data->ctx = NULL;
-               blk_queue_exit(q);
                return NULL;
        }
 
@@ -409,16 +406,19 @@ struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
        if (ret)
                return ERR_PTR(ret);
 
+       blk_queue_enter_live(q);
        rq = blk_mq_get_request(q, NULL, &alloc_data);
        blk_queue_exit(q);
 
        if (!rq)
-               return ERR_PTR(-EWOULDBLOCK);
-
+               goto out_queue_exit;
        rq->__data_len = 0;
        rq->__sector = (sector_t) -1;
        rq->bio = rq->biotail = NULL;
        return rq;
+out_queue_exit:
+       blk_queue_exit(q);
+       return ERR_PTR(-EWOULDBLOCK);
 }
 EXPORT_SYMBOL(blk_mq_alloc_request);
 
@@ -450,21 +450,24 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
         * Check if the hardware context is actually mapped to anything.
         * If not tell the caller that it should skip this queue.
         */
+       ret = -EXDEV;
        alloc_data.hctx = q->queue_hw_ctx[hctx_idx];
-       if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) {
-               blk_queue_exit(q);
-               return ERR_PTR(-EXDEV);
-       }
+       if (!blk_mq_hw_queue_mapped(alloc_data.hctx))
+               goto out_queue_exit;
        cpu = cpumask_first_and(alloc_data.hctx->cpumask, cpu_online_mask);
        alloc_data.ctx = __blk_mq_get_ctx(q, cpu);
 
+       ret = -EWOULDBLOCK;
+       blk_queue_enter_live(q);
        rq = blk_mq_get_request(q, NULL, &alloc_data);
        blk_queue_exit(q);
 
        if (!rq)
-               return ERR_PTR(-EWOULDBLOCK);
-
+               goto out_queue_exit;
        return rq;
+out_queue_exit:
+       blk_queue_exit(q);
+       return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
 
@@ -2043,8 +2046,10 @@ blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
        rq_qos_throttle(q, bio);
 
        data.cmd_flags = bio->bi_opf;
+       blk_queue_enter_live(q);
        rq = blk_mq_get_request(q, bio, &data);
        if (unlikely(!rq)) {
+               blk_queue_exit(q);
                rq_qos_cleanup(q, bio);
                if (bio->bi_opf & REQ_NOWAIT)
                        bio_wouldblock_error(bio);