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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: Al Viro <viro@zeniv.linux.org.uk>
master
Al Viro 8 years ago
parent
commit
aab407fc5c
  1. 8
      fs/proc_namespace.c

8
fs/proc_namespace.c

@ -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;
}

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