Only caller of alloc_cmd() is null_submit_bio() unconditionally sets
second parameter to true & that is statically hard-coded in null_blk.
There is no point in having statically hardcoded function parameter.
Remove the unnecessary parameter can_wait and adjust the code so it
can retain existing behavior of waiting when we don't get valid
nullb_cmd from __alloc_cmd() in alloc_cmd().
The restructured code avoids multiple return statements, multiple
calls to __alloc_cmd() and resulting a fast path call to
prepare_to_wait() due to removal of first alloc_cmd() call.
Signed-off-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
---
drivers/block/null_blk/main.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 13004beb48ca..d78fc3edb22e 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -719,26 +719,23 @@ 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 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;
-
+ 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)
@@ -1478,7 +1475,7 @@ static void null_submit_bio(struct bio *bio)
struct nullb_queue *nq = nullb_to_queue(nullb);
struct nullb_cmd *cmd;
- cmd = alloc_cmd(nq, 1);
+ cmd = alloc_cmd(nq);
cmd->bio = bio;
null_handle_cmd(cmd, sector, nr_sectors, bio_op(bio));
--
2.29.0
