nbd.c: sock_xmit: cleanup signal related code

sock_xmit() re-implements sigprocmask() and dequeue_signal_lock().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/block/nbd.c

@@ -122,17 +122,12 @@ static int sock_xmit(struct socket *sock, int send, void *buf, int size,
 	int result;
 	struct msghdr msg;
 	struct kvec iov;
-	unsigned long flags;
-	sigset_t oldset;
+	sigset_t blocked, oldset;
 
 	/* Allow interception of SIGKILL only
 	 * Don't allow other signals to interrupt the transmission */
-	spin_lock_irqsave(&current->sighand->siglock, flags);
-	oldset = current->blocked;
-	sigfillset(&current->blocked);
-	sigdelsetmask(&current->blocked, sigmask(SIGKILL));
-	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	siginitsetinv(&blocked, sigmask(SIGKILL));
+	sigprocmask(SIG_SETMASK, &blocked, &oldset);
 
 	do {
 		sock->sk->sk_allocation = GFP_NOIO;
@@ -151,11 +146,9 @@ static int sock_xmit(struct socket *sock, int send, void *buf, int size,
 
 		if (signal_pending(current)) {
 			siginfo_t info;
-			spin_lock_irqsave(&current->sighand->siglock, flags);
 			printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
 				current->pid, current->comm,
-				dequeue_signal(current, &current->blocked, &info));
-			spin_unlock_irqrestore(&current->sighand->siglock, flags);
+				dequeue_signal_lock(current, &current->blocked, &info));
 			result = -EINTR;
 			break;
 		}
@@ -169,10 +162,7 @@ static int sock_xmit(struct socket *sock, int send, void *buf, int size,
 		buf += result;
 	} while (size > 0);
 
-	spin_lock_irqsave(&current->sighand->siglock, flags);
-	current->blocked = oldset;
-	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	sigprocmask(SIG_SETMASK, &oldset, NULL);
 
 	return result;
 }