evie/android_kernel_oneplus_msm8998
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fanotify: convert access_mutex to spinlock

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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
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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; 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, list_for_each_entry(event, &group->fanotify_data.access_list,
fae.fse.list) { fae.fse.list) {
if (event->fd != fd) if (event->fd != fd)
@ -144,7 +144,7 @@ static struct fanotify_perm_event_info *dequeue_event(
return_e = event; return_e = event;
break; 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); 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 = FANOTIFY_PE(event);
pevent->fd = fd; pevent->fd = fd;
mutex_lock(&group->fanotify_data.access_mutex); spin_lock(&group->fanotify_data.access_lock);
list_add_tail(&pevent->fae.fse.list, list_add_tail(&pevent->fae.fse.list,
&group->fanotify_data.access_list); &group->fanotify_data.access_list);
mutex_unlock(&group->fanotify_data.access_mutex); spin_unlock(&group->fanotify_data.access_lock);
} }
#endif #endif
@ -346,7 +346,7 @@ static int fanotify_release(struct inode *ignored, struct file *file)
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
struct fanotify_perm_event_info *event, *next; 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); 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); list_del_init(&event->fae.fse.list);
event->response = FAN_ALLOW; 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); wake_up(&group->fanotify_data.access_waitq);
#endif #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; group->fanotify_data.f_flags = event_f_flags;
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS #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_waitqueue_head(&group->fanotify_data.access_waitq);
INIT_LIST_HEAD(&group->fanotify_data.access_list); INIT_LIST_HEAD(&group->fanotify_data.access_list);
atomic_set(&group->fanotify_data.bypass_perm, 0); 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 { struct fanotify_group_private_data {
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
/* allows a group to block waiting for a userspace response */ /* allows a group to block waiting for a userspace response */
struct mutex access_mutex; spinlock_t access_lock;
struct list_head access_list; struct list_head access_list;
wait_queue_head_t access_waitq; wait_queue_head_t access_waitq;
atomic_t bypass_perm; atomic_t bypass_perm;