ps3fb: atomic fixes

ps3fb: Use atomic_dec_if_positive() instead of bogus atomic_read()/atomic_dec()
combinations
Signed-off-by: NGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/video/ps3fb.c

@@ -680,13 +680,10 @@ EXPORT_SYMBOL_GPL(ps3fb_wait_for_vsync);
 
 void ps3fb_flip_ctl(int on)
 {
-	if (on) {
-		if (atomic_read(&ps3fb.ext_flip) > 0) {
-			atomic_dec(&ps3fb.ext_flip);
-		}
-	} else {
+	if (on)
+		atomic_dec_if_positive(&ps3fb.ext_flip);
+	else
 		atomic_inc(&ps3fb.ext_flip);
-	}
 }
 
 EXPORT_SYMBOL_GPL(ps3fb_flip_ctl);
@@ -786,8 +783,7 @@ static int ps3fb_ioctl(struct fb_info *info, unsigned int cmd,
 
 	case PS3FB_IOCTL_OFF:
 		DPRINTK("PS3FB_IOCTL_OFF:\n");
-		if (atomic_read(&ps3fb.ext_flip) > 0)
-			atomic_dec(&ps3fb.ext_flip);
+		atomic_dec_if_positive(&ps3fb.ext_flip);
 		retval = 0;
 		break;