Subject: + fanotify-convert-access_mutex-to-spinlock.patch added to -mm tree
To: jack@xxxxxxx,eparis@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 30 Jan 2014 14:01:33 -0800
The patch titled
Subject: fanotify: convert access_mutex to spinlock
has been added to the -mm tree. Its filename is
fanotify-convert-access_mutex-to-spinlock.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fanotify-convert-access_mutex-to-spinlock.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fanotify-convert-access_mutex-to-spinlock.patch
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------------------------------------------------------
From: Jan Kara <jack@xxxxxxx>
Subject: 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@xxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/notify/fanotify/fanotify_user.c | 14 +++++++-------
include/linux/fsnotify_backend.h | 2 +-
2 files changed, 8 insertions(+), 8 deletions(-)
diff -puN fs/notify/fanotify/fanotify_user.c~fanotify-convert-access_mutex-to-spinlock fs/notify/fanotify/fanotify_user.c
--- a/fs/notify/fanotify/fanotify_user.c~fanotify-convert-access_mutex-to-spinlock
+++ a/fs/notify/fanotify/fanotify_user.c
@@ -134,7 +134,7 @@ static struct fanotify_perm_event_info *
{
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 *
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
#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
#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
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
@@ -689,7 +689,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned
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 -puN include/linux/fsnotify_backend.h~fanotify-convert-access_mutex-to-spinlock include/linux/fsnotify_backend.h
--- a/include/linux/fsnotify_backend.h~fanotify-convert-access_mutex-to-spinlock
+++ a/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;
_
Patches currently in -mm which might be from jack@xxxxxxx are
origin.patch
fanotify-remove-useless-bypass_perm-check.patch
fanotify-use-fanotify-event-structure-for-permission-response-processing.patch
fanotify-remove-useless-test-from-event-initialization.patch
fanotify-convert-access_mutex-to-spinlock.patch
fanotify-reorganize-loop-in-fanotify_read.patch
fanotify-move-unrelated-handling-from-copy_event_to_user.patch
linux-next.patch
kernel-use-lockless-list-for-smp_call_function_single.patch
mm-add-strictlimit-knob-v2.patch
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