From: chengkaitao <chengkaitao@kylinos.cn>

Remove redundant DD_PRIO_MAX and enum types, Move DD_PRIO_COUNT
into enum dd_prio{}, and similarly for DD_DIR_COUNT.

Signed-off-by: chengkaitao <chengkaitao@kylinos.cn>
---
 block/mq-deadline.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index b9b7cdf1d3c9..f1facbdf85c1 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -41,19 +41,17 @@ static const int fifo_batch = 16;       /* # of sequential requests treated as o
 enum dd_data_dir {
 	DD_READ		= READ,
 	DD_WRITE	= WRITE,
+	DD_DIR_COUNT	= 2
 };
 
-enum { DD_DIR_COUNT = 2 };
-
+/* Ensure that "DD_RT_PRIO < DD_BE_PRIO < DD_IDLE_PRIO" */
 enum dd_prio {
-	DD_RT_PRIO	= 0,
-	DD_BE_PRIO	= 1,
-	DD_IDLE_PRIO	= 2,
-	DD_PRIO_MAX	= 2,
+	DD_RT_PRIO,
+	DD_BE_PRIO,
+	DD_IDLE_PRIO,
+	DD_PRIO_COUNT
 };
 
-enum { DD_PRIO_COUNT = 3 };
-
 /*
  * I/O statistics per I/O priority. It is fine if these counters overflow.
  * What matters is that these counters are at least as wide as
@@ -441,7 +439,7 @@ static struct request *dd_dispatch_prio_aged_requests(struct deadline_data *dd,
 	if (prio_cnt < 2)
 		return NULL;
 
-	for (prio = DD_BE_PRIO; prio <= DD_PRIO_MAX; prio++) {
+	for (prio = DD_BE_PRIO; prio < DD_PRIO_COUNT; prio++) {
 		rq = __dd_dispatch_request(dd, &dd->per_prio[prio],
 					   now - dd->prio_aging_expire);
 		if (rq)
@@ -475,7 +473,7 @@ static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx)
 	 * Next, dispatch requests in priority order. Ignore lower priority
 	 * requests if any higher priority requests are pending.
 	 */
-	for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
+	for (prio = 0; prio < DD_PRIO_COUNT; prio++) {
 		rq = __dd_dispatch_request(dd, &dd->per_prio[prio], now);
 		if (rq || dd_queued(dd, prio))
 			break;
@@ -530,7 +528,7 @@ static void dd_exit_sched(struct elevator_queue *e)
 	struct deadline_data *dd = e->elevator_data;
 	enum dd_prio prio;
 
-	for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
+	for (prio = 0; prio < DD_PRIO_COUNT; prio++) {
 		struct dd_per_prio *per_prio = &dd->per_prio[prio];
 		const struct io_stats_per_prio *stats = &per_prio->stats;
 		uint32_t queued;
@@ -565,7 +563,7 @@ static int dd_init_sched(struct request_queue *q, struct elevator_queue *eq)
 
 	eq->elevator_data = dd;
 
-	for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
+	for (prio = 0; prio < DD_PRIO_COUNT; prio++) {
 		struct dd_per_prio *per_prio = &dd->per_prio[prio];
 
 		INIT_LIST_HEAD(&per_prio->dispatch);
@@ -748,7 +746,7 @@ static bool dd_has_work(struct blk_mq_hw_ctx *hctx)
 	struct deadline_data *dd = hctx->queue->elevator->elevator_data;
 	enum dd_prio prio;
 
-	for (prio = 0; prio <= DD_PRIO_MAX; prio++)
+	for (prio = 0; prio < DD_PRIO_COUNT; prio++)
 		if (dd_has_work_for_prio(&dd->per_prio[prio]))
 			return true;
 
-- 
2.39.5 (Apple Git-154)

On 9/15/25 6:06 AM, chengkaitao wrote:
> Remove redundant DD_PRIO_MAX and enum types, Move DD_PRIO_COUNT
> into enum dd_prio{}, and similarly for DD_DIR_COUNT.

Why has this patch been reposted? Last time it was posted I explained in
detail that in my opinion all changes in this patch makes the code worse
instead of better. Additionally, when a new version of a patch is
posted, it should include a changelog. I don't see a changelog in this 
patch. Please drop this patch.

Bart.

On Mon, Sep 15, 2025 at 11:59 PM Bart Van Assche <bvanassche@acm.org> wrote:
>
> On 9/15/25 6:06 AM, chengkaitao wrote:
> > Remove redundant DD_PRIO_MAX and enum types, Move DD_PRIO_COUNT
> > into enum dd_prio{}, and similarly for DD_DIR_COUNT.
>
> Why has this patch been reposted? Last time it was posted I explained in
> detail that in my opinion all changes in this patch makes the code worse
> instead of better. Additionally, when a new version of a patch is
> posted, it should include a changelog. I don't see a changelog in this
> patch. Please drop this patch.
>
Regarding your comments on the previous patch, I have also provided a
detailed response. However, since I did not receive a reply for an extended
period, I am resubmitting it in hopes of continuing the discussion. This
patch is simply a repost with no substantial updates. The link to my previous
response is as follows.
https://lore.kernel.org/all/CAAWJmAbumBHVo-8neC+b8WqJzzLbWqARpc3vkBsgs9j08wh3kA@mail.gmail.com/

-- 
Yours,
Kaitao Cheng