Commit 67aec14c authored by Jens Axboe's avatar Jens Axboe
Browse files

blk-mq: make the sysfs mq/ layout reflect current mappings 



Currently blk-mq registers all the hardware queues in sysfs,
regardless of whether it uses them (e.g. they have CPU mappings)
or not. The unused hardware queues lack the cpux/ directories,
and the other sysfs entries (like active, pending, etc) are all
zeroes.

Change this so that sysfs correctly reflects the current mappings
of the hardware queues.

Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 22302375

block/blk-mq-sysfs.c

+83 −19
Original line number Diff line number Diff line
@@ -327,6 +327,42 @@ static struct kobj_type blk_mq_hw_ktype = { 
	.release	= blk_mq_sysfs_release,

};



void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)

{

	struct blk_mq_ctx *ctx;

	int i;



	if (!hctx->nr_ctx || !(hctx->flags & BLK_MQ_F_SYSFS_UP))

		return;



	hctx_for_each_ctx(hctx, ctx, i)

		kobject_del(&ctx->kobj);



	kobject_del(&hctx->kobj);

}



int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)

{

	struct request_queue *q = hctx->queue;

	struct blk_mq_ctx *ctx;

	int i, ret;



	if (!hctx->nr_ctx || !(hctx->flags & BLK_MQ_F_SYSFS_UP))

		return 0;



	ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", hctx->queue_num);

	if (ret)

		return ret;



	hctx_for_each_ctx(hctx, ctx, i) {

		ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);

		if (ret)

			break;

	}



	return ret;

}



void blk_mq_unregister_disk(struct gendisk *disk)

{

	struct request_queue *q = disk->queue;
@@ -335,11 +371,11 @@ void blk_mq_unregister_disk(struct gendisk *disk) 
	int i, j;



	queue_for_each_hw_ctx(q, hctx, i) {

		hctx_for_each_ctx(hctx, ctx, j) {

			kobject_del(&ctx->kobj);

		blk_mq_unregister_hctx(hctx);



		hctx_for_each_ctx(hctx, ctx, j)

			kobject_put(&ctx->kobj);

		}

		kobject_del(&hctx->kobj);



		kobject_put(&hctx->kobj);

	}
@@ -350,15 +386,30 @@ void blk_mq_unregister_disk(struct gendisk *disk) 
	kobject_put(&disk_to_dev(disk)->kobj);

}



static void blk_mq_sysfs_init(struct request_queue *q)

{

	struct blk_mq_hw_ctx *hctx;

	struct blk_mq_ctx *ctx;

	int i, j;



	kobject_init(&q->mq_kobj, &blk_mq_ktype);



	queue_for_each_hw_ctx(q, hctx, i) {

		kobject_init(&hctx->kobj, &blk_mq_hw_ktype);



		hctx_for_each_ctx(hctx, ctx, j)

			kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);

	}

}



int blk_mq_register_disk(struct gendisk *disk)

{

	struct device *dev = disk_to_dev(disk);

	struct request_queue *q = disk->queue;

	struct blk_mq_hw_ctx *hctx;

	struct blk_mq_ctx *ctx;

	int ret, i, j;

	int ret, i;



	kobject_init(&q->mq_kobj, &blk_mq_ktype);

	blk_mq_sysfs_init(q);



	ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");

	if (ret < 0)
@@ -367,21 +418,11 @@ int blk_mq_register_disk(struct gendisk *disk) 
	kobject_uevent(&q->mq_kobj, KOBJ_ADD);



	queue_for_each_hw_ctx(q, hctx, i) {

		kobject_init(&hctx->kobj, &blk_mq_hw_ktype);

		ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", i);

		if (ret)

			break;



		if (!hctx->nr_ctx)

			continue;



		hctx_for_each_ctx(hctx, ctx, j) {

			kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);

			ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);

		hctx->flags |= BLK_MQ_F_SYSFS_UP;

		ret = blk_mq_register_hctx(hctx);

		if (ret)

			break;

	}

	}



	if (ret) {

		blk_mq_unregister_disk(disk);
@@ -390,3 +431,26 @@ int blk_mq_register_disk(struct gendisk *disk) 


	return 0;

}



void blk_mq_sysfs_unregister(struct request_queue *q)

{

	struct blk_mq_hw_ctx *hctx;

	int i;



	queue_for_each_hw_ctx(q, hctx, i)

		blk_mq_unregister_hctx(hctx);

}



int blk_mq_sysfs_register(struct request_queue *q)

{

	struct blk_mq_hw_ctx *hctx;

	int i, ret = 0;



	queue_for_each_hw_ctx(q, hctx, i) {

		ret = blk_mq_register_hctx(hctx);

		if (ret)

			break;

	}



	return ret;

}

block/blk-mq.c

+4 −0
Original line number Diff line number Diff line
@@ -1924,6 +1924,8 @@ static void blk_mq_queue_reinit(struct request_queue *q) 
{

	blk_mq_freeze_queue(q);



	blk_mq_sysfs_unregister(q);



	blk_mq_update_queue_map(q->mq_map, q->nr_hw_queues);



	/*
@@ -1934,6 +1936,8 @@ static void blk_mq_queue_reinit(struct request_queue *q) 


	blk_mq_map_swqueue(q);



	blk_mq_sysfs_register(q);



	blk_mq_unfreeze_queue(q);

}

block/blk-mq.h

+6 −0
Original line number Diff line number Diff line
@@ -54,6 +54,12 @@ extern unsigned int *blk_mq_make_queue_map(struct blk_mq_tag_set *set); 
extern int blk_mq_update_queue_map(unsigned int *map, unsigned int nr_queues);

extern int blk_mq_hw_queue_to_node(unsigned int *map, unsigned int);



/*

 * sysfs helpers

 */

extern int blk_mq_sysfs_register(struct request_queue *q);

extern void blk_mq_sysfs_unregister(struct request_queue *q);



/*

 * Basic implementation of sparser bitmap, allowing the user to spread

 * the bits over more cachelines.

include/linux/blk-mq.h

+1 −0
Original line number Diff line number Diff line
@@ -130,6 +130,7 @@ enum { 
	BLK_MQ_F_SHOULD_SORT	= 1 << 1,

	BLK_MQ_F_TAG_SHARED	= 1 << 2,

	BLK_MQ_F_SG_MERGE	= 1 << 3,

	BLK_MQ_F_SYSFS_UP	= 1 << 4,



	BLK_MQ_S_STOPPED	= 0,

	BLK_MQ_S_TAG_ACTIVE	= 1,

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