Re: [PATCH RESEND v3 08/13] blk-mq: Don't clear driver tags own mapping

From: Hannes Reinecke
Date: Tue Sep 14 2021 - 01:46:02 EST


On 9/13/21 5:12 PM, John Garry wrote:
Function blk_mq_clear_rq_mapping() is required to clear the sched tags
mappings in driver tags rqs[].

But there is no need for a driver tags to clear its own mapping, so skip
clearing the mapping in this scenario.

Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
block/blk-mq.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4bae8afdfbe1..5229c5420b85 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2308,6 +2308,10 @@ static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
struct page *page;
unsigned long flags;
+ /* There is no need to clear a driver tags own mapping */
+ if (drv_tags == tags)
+ return;
+
list_for_each_entry(page, &tags->page_list, lru) {
unsigned long start = (unsigned long)page_address(page);
unsigned long end = start + order_to_size(page->private);

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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