commit 5a8da0ea82db6fa9737041381079fd16f25dcce2
author Roland McGrath <roland@redhat.com> Wed Apr 30 00:53:10 2008 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> Wed Apr 30 08:29:37 2008 -0700
tree abd26177c0a965315de290e1e9602d087b78f149
parent f3de272b821accbc8387211977c2de4f38468d05

signals: x86 TS_RESTORE_SIGMASK

Replace TIF_RESTORE_SIGMASK with TS_RESTORE_SIGMASK and define our own
set_restore_sigmask() function.  This saves the costly SMP-safe set_bit
operation, which we do not need for the sigmask flag since TIF_SIGPENDING
always has to be set too.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/signal_32.c

diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c
index 8e05e7f..d923736 100644
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -57,7 +57,7 @@
 
 	current->state = TASK_INTERRUPTIBLE;
 	schedule();
-	set_thread_flag(TIF_RESTORE_SIGMASK);
+	set_restore_sigmask();
 
 	return -ERESTARTNOHAND;
 }
@@ -593,7 +593,7 @@
 	if (!user_mode(regs))
 		return;
 
-	if (test_thread_flag(TIF_RESTORE_SIGMASK))
+	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 		oldset = &current->saved_sigmask;
 	else
 		oldset = &current->blocked;
@@ -612,13 +612,12 @@
 		/* Whee! Actually deliver the signal.  */
 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 			/*
-			 * a signal was successfully delivered; the saved
+			 * A signal was successfully delivered; the saved
 			 * sigmask will have been stored in the signal frame,
 			 * and will be restored by sigreturn, so we can simply
-			 * clear the TIF_RESTORE_SIGMASK flag
+			 * clear the TS_RESTORE_SIGMASK flag.
 			 */
-			if (test_thread_flag(TIF_RESTORE_SIGMASK))
-				clear_thread_flag(TIF_RESTORE_SIGMASK);
+			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 		}
 		return;
 	}
@@ -645,8 +644,8 @@
 	 * If there's no signal to deliver, we just put the saved sigmask
 	 * back.
 	 */
-	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
-		clear_thread_flag(TIF_RESTORE_SIGMASK);
+	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
+		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 	}
 }
@@ -665,7 +664,7 @@
 	}
 
 	/* deal with pending signal delivery */
-	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs);
 
 	if (thread_info_flags & _TIF_HRTICK_RESCHED)