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-rw-r--r--drivers/block/null_blk/main.c29
1 files changed, 12 insertions, 17 deletions
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 90b6bd2a114b..29e183719e77 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -720,26 +720,25 @@ static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
return NULL;
}
-static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
+static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, struct bio *bio)
{
struct nullb_cmd *cmd;
DEFINE_WAIT(wait);
- cmd = __alloc_cmd(nq);
- if (cmd || !can_wait)
- return cmd;
-
do {
- prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
+ /*
+ * This avoids multiple return statements, multiple calls to
+ * __alloc_cmd() and a fast path call to prepare_to_wait().
+ */
cmd = __alloc_cmd(nq);
- if (cmd)
- break;
-
+ if (cmd) {
+ cmd->bio = bio;
+ return cmd;
+ }
+ prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
io_schedule();
+ finish_wait(&nq->wait, &wait);
} while (1);
-
- finish_wait(&nq->wait, &wait);
- return cmd;
}
static void end_cmd(struct nullb_cmd *cmd)
@@ -1477,12 +1476,8 @@ static void null_submit_bio(struct bio *bio)
sector_t nr_sectors = bio_sectors(bio);
struct nullb *nullb = bio->bi_bdev->bd_disk->private_data;
struct nullb_queue *nq = nullb_to_queue(nullb);
- struct nullb_cmd *cmd;
-
- cmd = alloc_cmd(nq, 1);
- cmd->bio = bio;
- null_handle_cmd(cmd, sector, nr_sectors, bio_op(bio));
+ null_handle_cmd(alloc_cmd(nq, bio), sector, nr_sectors, bio_op(bio));
}
static bool should_timeout_request(struct request *rq)