Both blk_mq_map_swqueue() and blk_mq_realloc_hw_ctxs() are called before
the request queue is added to tagset list, so the two won't run concurrently
with blk_mq_update_nr_hw_queues().
When the two functions are only called from queue initialization or
blk_mq_update_nr_hw_queues(), elevator switch can't happen.
So remove these ->elevator_lock uses.
Reviewed-by: Nilay Shroff <nilay@xxxxxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/blk-mq.c | 19 ++++---------------
1 file changed, 4 insertions(+), 15 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 420150eb5a45..e08eda094ae7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4112,8 +4112,6 @@ static void blk_mq_map_swqueue(struct request_queue *q)
struct blk_mq_ctx *ctx;
struct blk_mq_tag_set *set = q->tag_set;
- mutex_lock(&q->elevator_lock);
-
queue_for_each_hw_ctx(q, hctx, i) {
cpumask_clear(hctx->cpumask);
hctx->nr_ctx = 0;
@@ -4218,8 +4216,6 @@ static void blk_mq_map_swqueue(struct request_queue *q)
hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
}
-
- mutex_unlock(&q->elevator_lock);
}
/*
@@ -4523,16 +4519,9 @@ static void __blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
}
static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
- struct request_queue *q, bool lock)
+ struct request_queue *q)
{
- if (lock) {
- /* protect against switching io scheduler */
- mutex_lock(&q->elevator_lock);
- __blk_mq_realloc_hw_ctxs(set, q);
- mutex_unlock(&q->elevator_lock);
- } else {
- __blk_mq_realloc_hw_ctxs(set, q);
- }
+ __blk_mq_realloc_hw_ctxs(set, q);
/* unregister cpuhp callbacks for exited hctxs */
blk_mq_remove_hw_queues_cpuhp(q);
@@ -4564,7 +4553,7 @@ int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
xa_init(&q->hctx_table);
- blk_mq_realloc_hw_ctxs(set, q, false);
+ blk_mq_realloc_hw_ctxs(set, q);
if (!q->nr_hw_queues)
goto err_hctxs;
@@ -4975,7 +4964,7 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
fallback:
blk_mq_update_queue_map(set);
list_for_each_entry(q, &set->tag_list, tag_set_list) {
- blk_mq_realloc_hw_ctxs(set, q, true);
+ blk_mq_realloc_hw_ctxs(set, q);
if (q->nr_hw_queues != set->nr_hw_queues) {
int i = prev_nr_hw_queues;
--
2.47.0
