On Thu, Sep 27, 2018 at 06:43:03PM +0800, Jianchao Wang wrote:
> blk-mq debugfs and sysfs entries need to be removed before updating
> queue map, otherwise, we get get wrong result there. This patch fixes
> it and remove the redundant debugfs and sysfs register/unregister
> operations during __blk_mq_update_nr_hw_queues.
>
> Signed-off-by: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
> ---
> block/blk-mq.c | 39 ++++++++++++---------------------------
> 1 file changed, 12 insertions(+), 27 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 85a1c1a..6356455 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2137,8 +2137,6 @@ static void blk_mq_exit_hctx(struct request_queue *q,
> struct blk_mq_tag_set *set,
> struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
> {
> - blk_mq_debugfs_unregister_hctx(hctx);
> -
> if (blk_mq_hw_queue_mapped(hctx))
> blk_mq_tag_idle(hctx);
>
> @@ -2165,6 +2163,7 @@ static void blk_mq_exit_hw_queues(struct request_queue *q,
> queue_for_each_hw_ctx(q, hctx, i) {
> if (i == nr_queue)
> break;
> + blk_mq_debugfs_unregister_hctx(hctx);
> blk_mq_exit_hctx(q, set, hctx, i);
> }
> }
> @@ -2222,8 +2221,6 @@ static int blk_mq_init_hctx(struct request_queue *q,
> if (hctx->flags & BLK_MQ_F_BLOCKING)
> init_srcu_struct(hctx->srcu);
>
> - blk_mq_debugfs_register_hctx(q, hctx);
> -
> return 0;
>
> free_fq:
> @@ -2512,8 +2509,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
> int i, j;
> struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
>
> - blk_mq_sysfs_unregister(q);
> -
> /* protect against switching io scheduler */
> mutex_lock(&q->sysfs_lock);
> for (i = 0; i < set->nr_hw_queues; i++) {
> @@ -2561,7 +2556,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
> }
> q->nr_hw_queues = i;
> mutex_unlock(&q->sysfs_lock);
> - blk_mq_sysfs_register(q);
> }
>
> struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
> @@ -2659,25 +2653,6 @@ void blk_mq_free_queue(struct request_queue *q)
> blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
> }
>
> -/* Basically redo blk_mq_init_queue with queue frozen */
> -static void blk_mq_queue_reinit(struct request_queue *q)
> -{
> - WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth));
> -
> - blk_mq_debugfs_unregister_hctxs(q);
> - blk_mq_sysfs_unregister(q);
> -
> - /*
> - * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
> - * we should change hctx numa_node according to the new topology (this
> - * involves freeing and re-allocating memory, worth doing?)
> - */
> - blk_mq_map_swqueue(q);
> -
> - blk_mq_sysfs_register(q);
> - blk_mq_debugfs_register_hctxs(q);
> -}
> -
> static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
> {
> int i;
> @@ -2987,11 +2962,21 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
> if (!blk_mq_elv_switch_none(&head, q))
> goto switch_back;
>
> + list_for_each_entry(q, &set->tag_list, tag_set_list) {
> + blk_mq_debugfs_unregister_hctxs(q);
> + blk_mq_sysfs_unregister(q);
> + }
> +
> set->nr_hw_queues = nr_hw_queues;
> blk_mq_update_queue_map(set);
> list_for_each_entry(q, &set->tag_list, tag_set_list) {
> blk_mq_realloc_hw_ctxs(set, q);
> - blk_mq_queue_reinit(q);
> + blk_mq_map_swqueue(q);
> + }
> +
> + list_for_each_entry(q, &set->tag_list, tag_set_list) {
> + blk_mq_sysfs_register(q);
> + blk_mq_debugfs_register_hctxs(q);
> }
>
> switch_back:
> --
> 2.7.4
>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Thanks,
Ming
