Commit 85e0cbbb authored by Luis Chamberlain's avatar Luis Chamberlain Committed by Jens Axboe
Browse files

block: create the request_queue debugfs_dir on registration 



We were only creating the request_queue debugfs_dir only
for make_request block drivers (multiqueue), but never for
request-based block drivers. We did this as we were only
creating non-blktrace additional debugfs files on that directory
for make_request drivers. However, since blktrace *always* creates
that directory anyway, we special-case the use of that directory
on blktrace. Other than this being an eye-sore, this exposes
request-based block drivers to the same debugfs fragile
race that used to exist with make_request block drivers
where if we start adding files onto that directory we can later
run a race with a double removal of dentries on the directory
if we don't deal with this carefully on blktrace.

Instead, just simplify things by always creating the request_queue
debugfs_dir on request_queue registration. Rename the mutex also to
reflect the fact that this is used outside of the blktrace context.

Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b431ef83

block/blk-core.c

+1 −7
Original line number Diff line number Diff line
@@ -51,9 +51,7 @@ 
#include "blk-pm.h"

#include "blk-rq-qos.h"



#ifdef CONFIG_DEBUG_FS

struct dentry *blk_debugfs_root;

#endif



EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);

EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
@@ -555,9 +553,7 @@ struct request_queue *__blk_alloc_queue(int node_id) 


	kobject_init(&q->kobj, &blk_queue_ktype);



#ifdef CONFIG_BLK_DEV_IO_TRACE

	mutex_init(&q->blk_trace_mutex);

#endif

	mutex_init(&q->debugfs_mutex);

	mutex_init(&q->sysfs_lock);

	mutex_init(&q->sysfs_dir_lock);

	spin_lock_init(&q->queue_lock);
@@ -1931,9 +1927,7 @@ int __init blk_dev_init(void) 
	blk_requestq_cachep = kmem_cache_create("request_queue",

			sizeof(struct request_queue), 0, SLAB_PANIC, NULL);



#ifdef CONFIG_DEBUG_FS

	blk_debugfs_root = debugfs_create_dir("block", NULL);

#endif



	return 0;

}

block/blk-mq-debugfs.c

+0 −5
Original line number Diff line number Diff line
@@ -824,9 +824,6 @@ void blk_mq_debugfs_register(struct request_queue *q) 
	struct blk_mq_hw_ctx *hctx;

	int i;



	q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),

					    blk_debugfs_root);



	debugfs_create_files(q->debugfs_dir, q, blk_mq_debugfs_queue_attrs);



	/*
@@ -857,9 +854,7 @@ void blk_mq_debugfs_register(struct request_queue *q) 


void blk_mq_debugfs_unregister(struct request_queue *q)

{

	debugfs_remove_recursive(q->debugfs_dir);

	q->sched_debugfs_dir = NULL;

	q->debugfs_dir = NULL;

}



static void blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,

block/blk-sysfs.c

+9 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/blktrace_api.h>

#include <linux/blk-mq.h>

#include <linux/blk-cgroup.h>

#include <linux/debugfs.h>



#include "blk.h"

#include "blk-mq.h"
@@ -917,6 +918,9 @@ static void blk_release_queue(struct kobject *kobj) 
		blk_mq_release(q);



	blk_trace_shutdown(q);

	mutex_lock(&q->debugfs_mutex);

	debugfs_remove_recursive(q->debugfs_dir);

	mutex_unlock(&q->debugfs_mutex);



	if (queue_is_mq(q))

		blk_mq_debugfs_unregister(q);
@@ -989,6 +993,11 @@ int blk_register_queue(struct gendisk *disk) 
		goto unlock;

	}



	mutex_lock(&q->debugfs_mutex);

	q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),

					    blk_debugfs_root);

	mutex_unlock(&q->debugfs_mutex);



	if (queue_is_mq(q)) {

		__blk_mq_register_dev(dev, q);

		blk_mq_debugfs_register(q);

block/blk.h

+0 −2
Original line number Diff line number Diff line
@@ -14,9 +14,7 @@ 
/* Max future timer expiry for timeouts */

#define BLK_MAX_TIMEOUT		(5 * HZ)



#ifdef CONFIG_DEBUG_FS

extern struct dentry *blk_debugfs_root;

#endif



struct blk_flush_queue {

	unsigned int		flush_pending_idx:1;

include/linux/blkdev.h

+3 −2
Original line number Diff line number Diff line
@@ -528,9 +528,9 @@ struct request_queue { 
	unsigned int		sg_timeout;

	unsigned int		sg_reserved_size;

	int			node;

	struct mutex		debugfs_mutex;

#ifdef CONFIG_BLK_DEV_IO_TRACE

	struct blk_trace __rcu	*blk_trace;

	struct mutex		blk_trace_mutex;

#endif

	/*

	 * for flush operations
@@ -574,8 +574,9 @@ struct request_queue { 
	struct list_head	tag_set_list;

	struct bio_set		bio_split;



#ifdef CONFIG_BLK_DEBUG_FS

	struct dentry		*debugfs_dir;



#ifdef CONFIG_BLK_DEBUG_FS

	struct dentry		*sched_debugfs_dir;

	struct dentry		*rqos_debugfs_dir;

#endif

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