Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit c75ec764 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
Browse files

sysfs: add sysfs_open_file_mutex 



Add a separate mutex to protect sysfs_open_dirent->buffers list.  This
will allow performing sleepable operations while traversing
sysfs_buffers, which will be renamed to sysfs_open_file.

Note that currently sysfs_open_dirent->buffers list isn't being used
for anything and this patch doesn't make any functional difference.
It will be used to merge regular and bin file supports.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 375b611e

fs/sysfs/file.c

+12 −6
Original line number Diff line number Diff line
@@ -25,15 +25,17 @@ 
#include "sysfs.h"



/*

 * There's one sysfs_buffer for each open file and one

 * sysfs_open_dirent for each sysfs_dirent with one or more open

 * files.

 * There's one sysfs_buffer for each open file and one sysfs_open_dirent

 * for each sysfs_dirent with one or more open files.

 *

 * filp->private_data points to sysfs_buffer and

 * sysfs_dirent->s_attr.open points to sysfs_open_dirent.  s_attr.open

 * is protected by sysfs_open_dirent_lock.

 * sysfs_dirent->s_attr.open points to sysfs_open_dirent.  s_attr.open is

 * protected by sysfs_open_dirent_lock.

 *

 * filp->private_data points to sysfs_buffer which is chained at

 * sysfs_open_dirent->buffers, which is protected by sysfs_open_file_mutex.

 */

static DEFINE_SPINLOCK(sysfs_open_dirent_lock);

static DEFINE_MUTEX(sysfs_open_file_mutex);



struct sysfs_open_dirent {

	atomic_t		refcnt;
@@ -272,6 +274,7 @@ static int sysfs_get_open_dirent(struct sysfs_dirent *sd, 
	struct sysfs_open_dirent *od, *new_od = NULL;



 retry:

	mutex_lock(&sysfs_open_file_mutex);

	spin_lock_irq(&sysfs_open_dirent_lock);



	if (!sd->s_attr.open && new_od) {
@@ -286,6 +289,7 @@ static int sysfs_get_open_dirent(struct sysfs_dirent *sd, 
	}



	spin_unlock_irq(&sysfs_open_dirent_lock);

	mutex_unlock(&sysfs_open_file_mutex);



	if (od) {

		kfree(new_od);
@@ -321,6 +325,7 @@ static void sysfs_put_open_dirent(struct sysfs_dirent *sd, 
	struct sysfs_open_dirent *od = sd->s_attr.open;

	unsigned long flags;



	mutex_lock(&sysfs_open_file_mutex);

	spin_lock_irqsave(&sysfs_open_dirent_lock, flags);



	list_del(&buffer->list);
@@ -330,6 +335,7 @@ static void sysfs_put_open_dirent(struct sysfs_dirent *sd, 
		od = NULL;



	spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);

	mutex_unlock(&sysfs_open_file_mutex);



	kfree(od);

}