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fanotify: convert access_mutex to spinlock 

access_mutex is used only to guard operations on access_list.  There's
no need for sleeping within this lock so just make a spinlock out of it.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Kara 2014-04-03 14:46:34 -07:00 committed by Linus Torvalds
parent f083441ba8
commit 9573f79355
2 changed files with 8 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
fs/notify/fanotify/fanotify_user.c
View File

@ -134,7 +134,7 @@ static struct fanotify_perm_event_info *dequeue_event(
{
struct fanotify_perm_event_info *event, *return_e = NULL;
mutex_lock(&group->fanotify_data.access_mutex);
spin_lock(&group->fanotify_data.access_lock);
list_for_each_entry(event, &group->fanotify_data.access_list,
fae.fse.list) {
if (event->fd != fd)
@ -144,7 +144,7 @@ static struct fanotify_perm_event_info *dequeue_event(
return_e = event;
break;
}
mutex_unlock(&group->fanotify_data.access_mutex);
spin_unlock(&group->fanotify_data.access_lock);
pr_debug("%s: found return_re=%p\n", __func__, return_e);
@ -213,10 +213,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
pevent = FANOTIFY_PE(event);
pevent->fd = fd;
mutex_lock(&group->fanotify_data.access_mutex);
spin_lock(&group->fanotify_data.access_lock);
list_add_tail(&pevent->fae.fse.list,
&group->fanotify_data.access_list);
mutex_unlock(&group->fanotify_data.access_mutex);
spin_unlock(&group->fanotify_data.access_lock);
}
#endif
@ -346,7 +346,7 @@ static int fanotify_release(struct inode *ignored, struct file *file)
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
struct fanotify_perm_event_info *event, *next;
mutex_lock(&group->fanotify_data.access_mutex);
spin_lock(&group->fanotify_data.access_lock);
atomic_inc(&group->fanotify_data.bypass_perm);
@ -358,7 +358,7 @@ static int fanotify_release(struct inode *ignored, struct file *file)
list_del_init(&event->fae.fse.list);
event->response = FAN_ALLOW;
}
mutex_unlock(&group->fanotify_data.access_mutex);
spin_unlock(&group->fanotify_data.access_lock);
wake_up(&group->fanotify_data.access_waitq);
#endif
@ -700,7 +700,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
group->fanotify_data.f_flags = event_f_flags;
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
mutex_init(&group->fanotify_data.access_mutex);
spin_lock_init(&group->fanotify_data.access_lock);
init_waitqueue_head(&group->fanotify_data.access_waitq);
INIT_LIST_HEAD(&group->fanotify_data.access_list);
atomic_set(&group->fanotify_data.bypass_perm, 0);

2
include/linux/fsnotify_backend.h
View File

@ -178,7 +178,7 @@ struct fsnotify_group {
struct fanotify_group_private_data {
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
/* allows a group to block waiting for a userspace response */
struct mutex access_mutex;
spinlock_t access_lock;
struct list_head access_list;
wait_queue_head_t access_waitq;
atomic_t bypass_perm;