From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Just like blk_mq_alloc_tag_set(), it's better to prepare all tags before
using to map to queue ctxs in blk_mq_map_swqueue(), which now have to
consider empty set->tags[].
The good point is that we can fallback easily if increasing nr_hw_queues
fail, instead of just mapping to hctx[0] when fail in blk_mq_map_swqueue().
And the fallback path already has tags free & clean handling, so all
is good.
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
block/blk-mq.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8d02bafff331..84adb3657b30 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4404,6 +4404,16 @@ static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
sizeof(*set->tags));
kfree(set->tags);
set->tags = new_tags;
+
+ for (i = set->nr_hw_queues; i < new_nr_hw_queues; i++) {
+ if (!__blk_mq_alloc_map_and_rqs(set, i)) {
+ while (--i >= set->nr_hw_queues)
+ __blk_mq_free_map_and_rqs(set, i);
+ return -ENOMEM;
+ }
+ cond_resched();
+ }
+
done:
set->nr_hw_queues = new_nr_hw_queues;
return 0;
--
2.41.0
