Re: [PATCH 5/5] blk-mq: Drop 'reserved' member of busy_tag_iter_fn

On 17/06/2022 17:33, Bart Van Assche wrote:

On 6/17/22 03:55, John Garry wrote:

quoted

We no longer use the 'reserved' member in for any iter function so it

                                          ^^^^^^
One of these two words probably should be removed.

Yeah, it's a typo - I can fix it.

quoted

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 2dcd738c6952..b8cc8b41553f 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c

@@ -266,7 +266,6 @@ static bool bt_iter(struct sbitmap *bitmap, 

unsigned int bitnr, void *data)
      struct blk_mq_hw_ctx *hctx = iter_data->hctx;
      struct request_queue *q = iter_data->q;
      struct blk_mq_tag_set *set = q->tag_set;
-    bool reserved = iter_data->reserved;
      struct blk_mq_tags *tags;
      struct request *rq;
      bool ret = true;

@@ -276,7 +275,7 @@ static bool bt_iter(struct sbitmap *bitmap, 

unsigned int bitnr, void *data)
      else
          tags = hctx->tags;
-    if (!reserved)
+    if (!iter_data->reserved)
          bitnr += tags->nr_reserved_tags;
      /*
       * We can hit rq == NULL here, because the tagging functions

Is the above change really necessary?

It's not totally necessary. Since local variable 'reserved' would now 
only be used once I thought it was better to get rid of it.

I can keep it if you really think that is better.

quoted

@@ -337,12 +336,11 @@ static bool bt_tags_iter(struct sbitmap *bitmap, 

unsigned int bitnr, void *data)
  {
      struct bt_tags_iter_data *iter_data = data;
      struct blk_mq_tags *tags = iter_data->tags;
-    bool reserved = iter_data->flags & BT_TAG_ITER_RESERVED;
      struct request *rq;
      bool ret = true;
      bool iter_static_rqs = !!(iter_data->flags & 
BT_TAG_ITER_STATIC_RQS);
-    if (!reserved)
+    if (!(iter_data->flags & BT_TAG_ITER_RESERVED))
          bitnr += tags->nr_reserved_tags;
      /*

Same question here: is the above change really necessary?

As above.

Thanks,
john