diff --git a/[refs] b/[refs]
index 1dd066f0eab1..6d5edc464896 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8243e636c060fe7c10c9cf3bf53fdd2d48901525
+refs/heads/master: 7a5ac8def9e0c77803c302b63c3f29e31a610415
diff --git a/trunk/drivers/parport/parport_pc.c b/trunk/drivers/parport/parport_pc.c
index d76d37bcb9cc..a85808938205 100644
--- a/trunk/drivers/parport/parport_pc.c
+++ b/trunk/drivers/parport/parport_pc.c
@@ -1568,9 +1568,8 @@ static void __devinit detect_and_report_it87(void)
 		outb(r | 8, 0x2F);
 		outb(0x02, 0x2E);	/* Lock */
 		outb(0x02, 0x2F);
-
-		release_region(0x2e, 1);
 	}
+	release_region(0x2e, 1);
 }
 #endif /* CONFIG_PARPORT_PC_SUPERIO */
 
diff --git a/trunk/fs/buffer.c b/trunk/fs/buffer.c
index 98196327ddf0..39ff14403d13 100644
--- a/trunk/fs/buffer.c
+++ b/trunk/fs/buffer.c
@@ -1181,7 +1181,20 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size)
 void mark_buffer_dirty(struct buffer_head *bh)
 {
 	WARN_ON_ONCE(!buffer_uptodate(bh));
-	if (!buffer_dirty(bh) && !test_set_buffer_dirty(bh))
+
+	/*
+	 * Very *carefully* optimize the it-is-already-dirty case.
+	 *
+	 * Don't let the final "is it dirty" escape to before we
+	 * perhaps modified the buffer.
+	 */
+	if (buffer_dirty(bh)) {
+		smp_mb();
+		if (buffer_dirty(bh))
+			return;
+	}
+
+	if (!test_set_buffer_dirty(bh))
 		__set_page_dirty(bh->b_page, page_mapping(bh->b_page), 0);
 }