autofs4: use wait_event_killable

This playing with signals to allow only fatal signals appears to predate
the introduction of wait_event_killable(), and I'm fairly sure that
wait_event_killable is what was meant to happen here.

[avagin@openvz.org: use wake_up() instead of wake_up_interruptible]
  Link: http://lkml.kernel.org/r/20180331022839.21277-1-avagin@openvz.org
Link: http://lkml.kernel.org/r/20180319191609.23880-1-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Ian Kent <raven@themaw.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/autofs4/waitq.c

@@ -19,9 +19,6 @@
  */
 static autofs_wqt_t autofs4_next_wait_queue = 1;
 
-/* These are the signals we allow interrupting a pending mount */
-#define SHUTDOWN_SIGS	(sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
-
 void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
 {
 	struct autofs_wait_queue *wq, *nwq;
@@ -486,29 +483,7 @@ int autofs4_wait(struct autofs_sb_info *sbi,
 	 * wq->name.name is NULL iff the lock is already released
 	 * or the mount has been made catatonic.
 	 */
-	if (wq->name.name) {
-		/* Block all but "shutdown" signals while waiting */
-		unsigned long shutdown_sigs_mask;
-		unsigned long irqflags;
-		sigset_t oldset;
-
-		spin_lock_irqsave(&current->sighand->siglock, irqflags);
-		oldset = current->blocked;
-		shutdown_sigs_mask = SHUTDOWN_SIGS & ~oldset.sig[0];
-		siginitsetinv(&current->blocked, shutdown_sigs_mask);
-		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
-
-		wait_event_interruptible(wq->queue, wq->name.name == NULL);
-
-		spin_lock_irqsave(&current->sighand->siglock, irqflags);
-		current->blocked = oldset;
-		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
-	} else {
-		pr_debug("skipped sleeping\n");
-	}
-
+	wait_event_killable(wq->queue, wq->name.name == NULL);
 	status = wq->status;
 
 	/*
@@ -574,7 +549,7 @@ int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_tok
 	kfree(wq->name.name);
 	wq->name.name = NULL;	/* Do not wait on this queue */
 	wq->status = status;
-	wake_up_interruptible(&wq->queue);
+	wake_up(&wq->queue);
 	if (!--wq->wait_ctr)
 		kfree(wq);
 	mutex_unlock(&sbi->wq_mutex);