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Commit 7ea5fe31 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq: make lifetime consitent between q/ctx and its kobject 



Currently from kobject view, both q->mq_kobj and ctx->kobj can
be released during one cycle of blk_mq_register_dev() and
blk_mq_unregister_dev(). Actually, sw queue's lifetime is
same with its request queue's, which is covered by request_queue->kobj.

So we don't need to call kobject_put() for the two kinds of
kobject in __blk_mq_unregister_dev(), instead we do that
in release handler of request queue.

Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
Tested-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 737f98cf

block/blk-mq-sysfs.c

+13 −7
Original line number Diff line number Diff line
@@ -242,15 +242,11 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx) 
static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)

{

	struct blk_mq_hw_ctx *hctx;

	struct blk_mq_ctx *ctx;

	int i, j;

	int i;



	queue_for_each_hw_ctx(q, hctx, i) {

		blk_mq_unregister_hctx(hctx);



		hctx_for_each_ctx(hctx, ctx, j)

			kobject_put(&ctx->kobj);



		kobject_put(&hctx->kobj);

	}
@@ -258,8 +254,6 @@ static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q) 


	kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);

	kobject_del(&q->mq_kobj);

	kobject_put(&q->mq_kobj);



	kobject_put(&dev->kobj);



	q->mq_sysfs_init_done = false;
@@ -277,6 +271,18 @@ void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx) 
	kobject_init(&hctx->kobj, &blk_mq_hw_ktype);

}



void blk_mq_sysfs_deinit(struct request_queue *q)

{

	struct blk_mq_ctx *ctx;

	int cpu;



	for_each_possible_cpu(cpu) {

		ctx = per_cpu_ptr(q->queue_ctx, cpu);

		kobject_put(&ctx->kobj);

	}

	kobject_put(&q->mq_kobj);

}



void blk_mq_sysfs_init(struct request_queue *q)

{

	struct blk_mq_ctx *ctx;

block/blk-mq.c

+6 −1
Original line number Diff line number Diff line
@@ -2264,7 +2264,12 @@ void blk_mq_release(struct request_queue *q) 


	kfree(q->queue_hw_ctx);



	/* ctx kobj stays in queue_ctx */

	/*

	 * release .mq_kobj and sw queue's kobject now because

	 * both share lifetime with request queue.

	 */

	blk_mq_sysfs_deinit(q);



	free_percpu(q->queue_ctx);

}

block/blk-mq.h

+1 −0
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q, 
 * sysfs helpers

 */

extern void blk_mq_sysfs_init(struct request_queue *q);

extern void blk_mq_sysfs_deinit(struct request_queue *q);

extern int blk_mq_sysfs_register(struct request_queue *q);

extern void blk_mq_sysfs_unregister(struct request_queue *q);

extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);