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Commit 07e4fead authored by Omar Sandoval's avatar Omar Sandoval Committed by Jens Axboe
Browse files

blk-mq: create debugfs directory tree 



In preparation for putting blk-mq debugging information in debugfs,
create a directory tree mirroring the one in sysfs:

    # tree -d /sys/kernel/debug/block
    /sys/kernel/debug/block
    |-- nvme0n1
    |   `-- mq
    |       |-- 0
    |       |   `-- cpu0
    |       |-- 1
    |       |   `-- cpu1
    |       |-- 2
    |       |   `-- cpu2
    |       `-- 3
    |           `-- cpu3
    `-- vda
        `-- mq
            `-- 0
                |-- cpu0
                |-- cpu1
                |-- cpu2
                `-- cpu3

Also add the scaffolding for the actual files that will go in here,
either under the hardware queue or software queue directories.

Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent b48fda09

block/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -26,3 +26,4 @@ obj-$(CONFIG_BLK_DEV_INTEGRITY) += bio-integrity.o blk-integrity.o t10-pi.o 
obj-$(CONFIG_BLK_MQ_PCI)	+= blk-mq-pci.o

obj-$(CONFIG_BLK_DEV_ZONED)	+= blk-zoned.o

obj-$(CONFIG_BLK_WBT)		+= blk-wbt.o

obj-$(CONFIG_DEBUG_FS)		+= blk-mq-debugfs.o

block/blk-mq-debugfs.c

0 → 100644
+152 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 Facebook

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public

 * License v2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */



#include <linux/kernel.h>

#include <linux/blkdev.h>

#include <linux/debugfs.h>



#include <linux/blk-mq.h>

#include "blk-mq.h"



struct blk_mq_debugfs_attr {

	const char *name;

	umode_t mode;

	const struct file_operations *fops;

};



static struct dentry *block_debugfs_root;



static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {

};



static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {

};



int blk_mq_debugfs_register(struct request_queue *q, const char *name)

{

	if (!block_debugfs_root)

		return -ENOENT;



	q->debugfs_dir = debugfs_create_dir(name, block_debugfs_root);

	if (!q->debugfs_dir)

		goto err;



	if (blk_mq_debugfs_register_hctxs(q))

		goto err;



	return 0;



err:

	blk_mq_debugfs_unregister(q);

	return -ENOMEM;

}



void blk_mq_debugfs_unregister(struct request_queue *q)

{

	debugfs_remove_recursive(q->debugfs_dir);

	q->mq_debugfs_dir = NULL;

	q->debugfs_dir = NULL;

}



static int blk_mq_debugfs_register_ctx(struct request_queue *q,

				       struct blk_mq_ctx *ctx,

				       struct dentry *hctx_dir)

{

	struct dentry *ctx_dir;

	char name[20];

	int i;



	snprintf(name, sizeof(name), "cpu%u", ctx->cpu);

	ctx_dir = debugfs_create_dir(name, hctx_dir);

	if (!ctx_dir)

		return -ENOMEM;



	for (i = 0; i < ARRAY_SIZE(blk_mq_debugfs_ctx_attrs); i++) {

		const struct blk_mq_debugfs_attr *attr;



		attr = &blk_mq_debugfs_ctx_attrs[i];

		if (!debugfs_create_file(attr->name, attr->mode, ctx_dir, ctx,

					 attr->fops))

			return -ENOMEM;

	}



	return 0;

}



static int blk_mq_debugfs_register_hctx(struct request_queue *q,

					struct blk_mq_hw_ctx *hctx)

{

	struct blk_mq_ctx *ctx;

	struct dentry *hctx_dir;

	char name[20];

	int i;



	snprintf(name, sizeof(name), "%u", hctx->queue_num);

	hctx_dir = debugfs_create_dir(name, q->mq_debugfs_dir);

	if (!hctx_dir)

		return -ENOMEM;



	for (i = 0; i < ARRAY_SIZE(blk_mq_debugfs_hctx_attrs); i++) {

		const struct blk_mq_debugfs_attr *attr;



		attr = &blk_mq_debugfs_hctx_attrs[i];

		if (!debugfs_create_file(attr->name, attr->mode, hctx_dir, hctx,

					 attr->fops))

			return -ENOMEM;

	}



	hctx_for_each_ctx(hctx, ctx, i) {

		if (blk_mq_debugfs_register_ctx(q, ctx, hctx_dir))

			return -ENOMEM;

	}



	return 0;

}



int blk_mq_debugfs_register_hctxs(struct request_queue *q)

{

	struct blk_mq_hw_ctx *hctx;

	int i;



	if (!q->debugfs_dir)

		return -ENOENT;



	q->mq_debugfs_dir = debugfs_create_dir("mq", q->debugfs_dir);

	if (!q->mq_debugfs_dir)

		goto err;



	queue_for_each_hw_ctx(q, hctx, i) {

		if (blk_mq_debugfs_register_hctx(q, hctx))

			goto err;

	}



	return 0;



err:

	blk_mq_debugfs_unregister_hctxs(q);

	return -ENOMEM;

}



void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)

{

	debugfs_remove_recursive(q->mq_debugfs_dir);

	q->mq_debugfs_dir = NULL;

}



void blk_mq_debugfs_init(void)

{

	block_debugfs_root = debugfs_create_dir("block", NULL);

}

block/blk-mq-sysfs.c

+8 −0
Original line number Diff line number Diff line
@@ -468,6 +468,8 @@ static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q) 
		kobject_put(&hctx->kobj);

	}



	blk_mq_debugfs_unregister(q);



	kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);

	kobject_del(&q->mq_kobj);

	kobject_put(&q->mq_kobj);
@@ -517,6 +519,8 @@ int blk_mq_register_dev(struct device *dev, struct request_queue *q) 


	kobject_uevent(&q->mq_kobj, KOBJ_ADD);



	blk_mq_debugfs_register(q, kobject_name(&dev->kobj));



	queue_for_each_hw_ctx(q, hctx, i) {

		ret = blk_mq_register_hctx(hctx);

		if (ret)
@@ -542,6 +546,8 @@ void blk_mq_sysfs_unregister(struct request_queue *q) 
	if (!q->mq_sysfs_init_done)

		return;



	blk_mq_debugfs_unregister_hctxs(q);



	queue_for_each_hw_ctx(q, hctx, i)

		blk_mq_unregister_hctx(hctx);

}
@@ -554,6 +560,8 @@ int blk_mq_sysfs_register(struct request_queue *q) 
	if (!q->mq_sysfs_init_done)

		return ret;



	blk_mq_debugfs_register_hctxs(q);



	queue_for_each_hw_ctx(q, hctx, i) {

		ret = blk_mq_register_hctx(hctx);

		if (ret)

block/blk-mq.c

+2 −0
Original line number Diff line number Diff line
@@ -2799,6 +2799,8 @@ void blk_mq_enable_hotplug(void) 


static int __init blk_mq_init(void)

{

	blk_mq_debugfs_init();



	cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,

				blk_mq_hctx_notify_dead);

block/blk-mq.h

+33 −0
Original line number Diff line number Diff line
@@ -78,6 +78,39 @@ 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);



/*

 * debugfs helpers

 */

#ifdef CONFIG_DEBUG_FS

void blk_mq_debugfs_init(void);

int blk_mq_debugfs_register(struct request_queue *q, const char *name);

void blk_mq_debugfs_unregister(struct request_queue *q);

int blk_mq_debugfs_register_hctxs(struct request_queue *q);

void blk_mq_debugfs_unregister_hctxs(struct request_queue *q);

#else

static inline void blk_mq_debugfs_init(void)

{

}



int blk_mq_debugfs_register(struct request_queue *q, const char *name);

{

	return 0;

}



void blk_mq_debugfs_unregister(struct request_queue *q)

{

}



int blk_mq_debugfs_register_hctxs(struct request_queue *q)

{

	return 0;

}



void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)

{

}

#endif



extern void blk_mq_rq_timed_out(struct request *req, bool reserved);



void blk_mq_release(struct request_queue *q);