Commit 17ab4994 authored by Luis Chamberlain's avatar Luis Chamberlain Committed by Yu Kuai
Browse files

block: create the request_queue debugfs_dir on registration 

mainline inclusion
from mainline-v5.9-rc1
commit 85e0cbbb
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/IAGRKP
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=85e0cbbb8a79537dbc465e9deb449a08b2b092a6



--------------------------------

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>
Conflicts:
	block/blk-core.c
	block/blk-sysfs.c
	block/blk.h
	include/linux/blkdev.h
	kernel/trace/blktrace.c
[Context conflicts]
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
parent 2b7f7767

block/blk-core.c

+1 −7
Original line number Diff line number Diff line
@@ -45,9 +45,7 @@ 
#include "blk-rq-qos.h"

#include "blk-io-hierarchy/stats.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);
@@ -1346,9 +1344,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, 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_wrapper->sysfs_dir_lock);

	spin_lock_init(&q->__queue_lock);
@@ -4307,9 +4303,7 @@ int __init blk_dev_init(void) 


	init_blk_queue_async_dispatch();



#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
@@ -841,9 +841,6 @@ 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);



	/*
@@ -867,9 +864,7 @@ 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 <linux/atomic.h>



#include "blk.h"
@@ -895,6 +896,9 @@ static void __blk_release_queue(struct work_struct *work) 
	}



	blk_trace_shutdown(q);

	mutex_lock(&q->debugfs_mutex);

	debugfs_remove_recursive(q->debugfs_dir);

	mutex_unlock(&q->debugfs_mutex);



	if (q->mq_ops)

		blk_mq_debugfs_unregister(q);
@@ -968,6 +972,11 @@ 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 (q->mq_ops) {

		__blk_mq_register_dev(dev, q);

		blk_mq_debugfs_register(q);

block/blk.h

+0 −2
Original line number Diff line number Diff line
@@ -15,9 +15,7 @@ 
/* 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_queue_delayed:1;

include/linux/blkdev.h

+2 −2
Original line number Diff line number Diff line
@@ -641,9 +641,9 @@ 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
@@ -689,8 +689,8 @@ 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;

#endif