Commit aab407fc authored by Al Viro's avatar Al Viro
Browse files

don't bother with vfsmount_lock in mounts_poll() 



wake_up_interruptible/poll_wait provide sufficient barriers;
just use ACCESS_ONCE() to fetch ns->event and that's it.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent aba809cf

fs/proc_namespace.c

+4 −4
Original line number Diff line number Diff line
@@ -20,15 +20,15 @@ static unsigned mounts_poll(struct file *file, poll_table *wait) 
	struct proc_mounts *p = proc_mounts(file->private_data);

	struct mnt_namespace *ns = p->ns;

	unsigned res = POLLIN | POLLRDNORM;

	int event;



	poll_wait(file, &p->ns->poll, wait);



	br_read_lock(&vfsmount_lock);

	if (p->m.poll_event != ns->event) {

		p->m.poll_event = ns->event;

	event = ACCESS_ONCE(ns->event);

	if (p->m.poll_event != event) {

		p->m.poll_event = event;

		res |= POLLERR | POLLPRI;

	}

	br_read_unlock(&vfsmount_lock);



	return res;

}