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Date: Mon, 3 Mar 2014 12:12:21 +0100
From: Jan Kara <jack@...e.cz>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: LKML <linux-kernel@...r.kernel.org>, linux-fsdevel@...r.kernel.org,
Eric Paris <eparis@...isplace.org>, Jan Kara <jack@...e.cz>
Subject: [PATCH 3/5] 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@...e.cz>
---
fs/notify/fanotify/fanotify_user.c | 14 +++++++-------
include/linux/fsnotify_backend.h | 2 +-
2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 517732dedee2..e0379d725cd9 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -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);
@@ -210,10 +210,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
if (event->mask & FAN_ALL_PERM_EVENTS) {
FANOTIFY_PE(event)->fd = fd;
- mutex_lock(&group->fanotify_data.access_mutex);
+ spin_lock(&group->fanotify_data.access_lock);
list_add_tail(&event->fae.fse.list,
&group->fanotify_data.access_list);
- mutex_unlock(&group->fanotify_data.access_mutex);
+ spin_unlock(&group->fanotify_data.access_lock);
}
#endif
@@ -343,7 +343,7 @@ 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);
@@ -355,7 +355,7 @@ 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
@@ -697,7 +697,7 @@ 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);
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 64cf3ef50696..fc7718c6bd3e 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -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;
--
1.8.1.4
--
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