[PATCH V4 4/8] null_blk: don't use magic numbers in the code

Chaitanya Kulkarni
2022-11-29T23:29:36Z

Instead of using the hardcoded value use meaningful macro for tag
available value of -1U in get_tag() and __alloc_cmd().

While at it return early on error to get rid of the extra indentation
in __alloc_cmd().

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
---
drivers/block/null_blk/main.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 84f5ca0cc79c..db849e6bc475 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -24,6 +24,8 @@
#define TICKS_PER_SEC 50ULL
#define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC)

+#define NULL_REQ_TAG_NOT_AVAILABLE (-1U)
+
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
static DECLARE_FAULT_ATTR(null_timeout_attr);
static DECLARE_FAULT_ATTR(null_requeue_attr);
@@ -730,7 +732,7 @@ static unsigned int get_tag(struct nullb_queue *nq)
do {
tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
if (tag >= nq->queue_depth)
- return -1U;
+ return NULL_REQ_TAG_NOT_AVAILABLE;
} while (test_and_set_bit_lock(tag, nq->tag_map));

return tag;
@@ -749,21 +751,19 @@ static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq, struct bio *bio)
unsigned int tag;

tag = get_tag(nq);
- if (tag != -1U) {
- cmd = &nq->cmds[tag];
- cmd->tag = tag;
- cmd->error = BLK_STS_OK;
- cmd->nq = nq;
- cmd->bio = bio;
- if (nq->dev->irqmode == NULL_IRQ_TIMER) {
- hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
- HRTIMER_MODE_REL);
- cmd->timer.function = null_cmd_timer_expired;
- }
- return cmd;
+ if (tag == NULL_REQ_TAG_NOT_AVAILABLE)
+ return NULL;
+ cmd = &nq->cmds[tag];
+ cmd->tag = tag;
+ cmd->error = BLK_STS_OK;
+ cmd->nq = nq;
+ cmd->bio = bio;
+ if (nq->dev->irqmode == NULL_IRQ_TIMER) {
+ hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
+ HRTIMER_MODE_REL);
+ cmd->timer.function = null_cmd_timer_expired;
}
-
- return NULL;
+ return cmd;
}

static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, struct bio *bio)
--
2.29.0