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fsnotify: convert notification_mutex to a spinlock

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notification_mutex is used to protect the list of pending events.  As such
there's no reason to use a sleeping lock for it.  Convert it to a
spinlock.

[jack@suse.cz: fixed version]
  Link: http://lkml.kernel.org/r/1474031567-1831-1-git-send-email-jack@suse.cz
Link: http://lkml.kernel.org/r/1473797711-14111-5-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Miklos Szeredi <mszeredi@redhat.com>
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
2016-10-07 16:56:52 -07:00
committed by Linus Torvalds
parent 1404ff3cc3
commit c21dbe20f6
5 changed files with 41 additions and 37 deletions
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16
fs/notify/inotify/inotify_user.c
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@@ -115,10 +115,10 @@ static unsigned int inotify_poll(struct file *file, poll_table *wait)
int ret = 0;
poll_wait(file, &group->notification_waitq, wait);
mutex_lock(&group->notification_mutex);
spin_lock(&group->notification_lock);
if (!fsnotify_notify_queue_is_empty(group))
ret = POLLIN | POLLRDNORM;
mutex_unlock(&group->notification_mutex);
spin_unlock(&group->notification_lock);
return ret;
}
@@ -138,7 +138,7 @@ static int round_event_name_len(struct fsnotify_event *fsn_event)
* enough to fit in "count". Return an error pointer if
* not large enough.
*
* Called with the group->notification_mutex held.
* Called with the group->notification_lock held.
*/
static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
size_t count)
@@ -157,7 +157,7 @@ static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
if (event_size > count)
return ERR_PTR(-EINVAL);
/* held the notification_mutex the whole time, so this is the
/* held the notification_lock the whole time, so this is the
* same event we peeked above */
fsnotify_remove_first_event(group);
@@ -234,9 +234,9 @@ static ssize_t inotify_read(struct file *file, char __user *buf,
add_wait_queue(&group->notification_waitq, &wait);
while (1) {
mutex_lock(&group->notification_mutex);
spin_lock(&group->notification_lock);
kevent = get_one_event(group, count);
mutex_unlock(&group->notification_mutex);
spin_unlock(&group->notification_lock);
pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent);
@@ -300,13 +300,13 @@ static long inotify_ioctl(struct file *file, unsigned int cmd,
switch (cmd) {
case FIONREAD:
mutex_lock(&group->notification_mutex);
spin_lock(&group->notification_lock);
list_for_each_entry(fsn_event, &group->notification_list,
list) {
send_len += sizeof(struct inotify_event);
send_len += round_event_name_len(fsn_event);
}
mutex_unlock(&group->notification_mutex);
spin_unlock(&group->notification_lock);
ret = put_user(send_len, (int __user *) p);
break;
}