[2/3] filtered buffer_head wakeups

[William Lee Irwin III]

On Tue, May 04, 2004 at 11:08:49PM -0700, William Lee Irwin III wrote:
> Precisely the same filtered wakeups for pages as before. Drop in a
> fresh wakeup primitive that uses a key to discriminate between the
> waiters for different objects on a hashed waitqueue, and make the
> page waiting functions use it.

Now, make bh's use the new wakeup primitive also. This has the bugfix
vs. the prior version that autoremoved waitqueue wakeup functions are
made to match autoremove API usage in __wait_event_filtered().


-- wli

Index: wake-2.6.6-rc3-mm1/fs/buffer.c
===================================================================
--- wake-2.6.6-rc3-mm1.orig/fs/buffer.c	2004-04-30 15:06:46.000000000 -0700
+++ wake-2.6.6-rc3-mm1/fs/buffer.c	2004-05-04 13:16:16.000000000 -0700
@@ -74,7 +74,7 @@
 
 	smp_mb();
 	if (waitqueue_active(wq))
-		wake_up_all(wq);
+		wake_up_filtered(wq, bh);
 }
 EXPORT_SYMBOL(wake_up_buffer);
 
@@ -93,10 +93,10 @@
 void __wait_on_buffer(struct buffer_head * bh)
 {
 	wait_queue_head_t *wqh = bh_waitq_head(bh);
-	DEFINE_WAIT(wait);
+	DEFINE_FILTERED_WAIT(wait, bh);
 
 	do {
-		prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
+		prepare_to_wait(wqh, &wait.wait, TASK_UNINTERRUPTIBLE);
 		if (buffer_locked(bh)) {
 			struct block_device *bd;
 			smp_mb();
@@ -106,7 +106,7 @@
 			io_schedule();
 		}
 	} while (buffer_locked(bh));
-	finish_wait(wqh, &wait);
+	finish_wait(wqh, &wait.wait);
 }
 
 static void
Index: wake-2.6.6-rc3-mm1/fs/jbd/transaction.c
===================================================================
--- wake-2.6.6-rc3-mm1.orig/fs/jbd/transaction.c	2004-04-30 15:06:46.000000000 -0700
+++ wake-2.6.6-rc3-mm1/fs/jbd/transaction.c	2004-05-04 13:16:16.000000000 -0700
@@ -638,7 +638,7 @@
 			jbd_unlock_bh_state(bh);
 			/* commit wakes up all shadow buffers after IO */
 			wqh = bh_waitq_head(jh2bh(jh));
-			wait_event(*wqh, (jh->b_jlist != BJ_Shadow));
+			wait_event_filtered(*wqh, jh2bh(jh), (jh->b_jlist != BJ_Shadow));
 			goto repeat;
 		}
 
Index: wake-2.6.6-rc3-mm1/include/linux/wait.h
===================================================================
--- wake-2.6.6-rc3-mm1.orig/include/linux/wait.h	2004-05-04 13:16:00.000000000 -0700
+++ wake-2.6.6-rc3-mm1/include/linux/wait.h	2004-05-04 13:16:27.000000000 -0700
@@ -146,7 +146,6 @@
 		break;							\
 	__wait_event(wq, condition);					\
 } while (0)
-
 #define __wait_event_interruptible(wq, condition, ret)			\
 do {									\
 	wait_queue_t __wait;						\
@@ -273,7 +272,28 @@
 			.task_list = LIST_HEAD_INIT(name.wait.task_list),\
 		},							\
 	}
-	
+
+#define __wait_event_filtered(wq, key, condition) 			\
+do {									\
+	DEFINE_FILTERED_WAIT(__wait, key);				\
+	wait_queue_head_t *__wqh = &(wq);				\
+	wait_queue_t *__wqe = &__wait.wait;				\
+	for (;;) {							\
+		prepare_to_wait(__wqh, __wqe, TASK_UNINTERRUPTIBLE);	\
+		if (condition)						\
+			break;						\
+		schedule();						\
+	}								\
+	finish_wait(__wqh, __wqe);					\
+} while (0)
+
+
+#define wait_event_filtered(wq, key, condition)				\
+do {									\
+	if (!(condition))						\
+		__wait_event_filtered(wq, key, condition);		\
+} while (0)
+
 #endif /* __KERNEL__ */
 
 #endif
-
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