6.5-stable review patch. If anyone has any objections, please let me know.
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From: Chengming Zhou zhouchengming@bytedance.com
commit 7222657e51b5626d10154b3e48ad441c33b5da96 upstream.
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@bytedance.com Reviewed-by: Ming Lei ming.lei@redhat.com Link: https://lore.kernel.org/r/20230821095602.70742-3-chengming.zhou@linux.dev Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-mq.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4420,6 +4420,16 @@ static int blk_mq_realloc_tag_set_tags(s 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;