[tip:sched/core] sched/wait: Add __wake_up_all_locked() API

[tip-bot for Thomas Gleixner]

Commit-ID:  63b2001169e75cd71e917ec953fdab572e3f944a
Gitweb:     http://git.kernel.org/tip/63b2001169e75cd71e917ec953fdab572e3f944a
Author:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 1 Dec 2011 00:04:00 +0100
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 1 Mar 2012 10:28:04 +0100

sched/wait: Add __wake_up_all_locked() API

For code which protects the waitqueue itself with another lock it
makes no sense to acquire the waitqueue lock for wakeup all. Provide
__wake_up_all_locked().

This is an optimization on the vanilla kernel (to be used by the
PCI code) and an important semantic distinction on -rt.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-ux6m4b8jonb9inx8xafh77ds@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
 include/linux/wait.h |    5 +++--
 kernel/sched/core.c  |    4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/wait.h b/include/linux/wait.h
index a9ce45e..7d9a9e9 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -157,7 +157,7 @@ void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
 			void *key);
-void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
+void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 void __wake_up_bit(wait_queue_head_t *, void *, int);
 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
@@ -170,7 +170,8 @@ wait_queue_head_t *bit_waitqueue(void *, int);
 #define wake_up(x)			__wake_up(x, TASK_NORMAL, 1, NULL)
 #define wake_up_nr(x, nr)		__wake_up(x, TASK_NORMAL, nr, NULL)
 #define wake_up_all(x)			__wake_up(x, TASK_NORMAL, 0, NULL)
-#define wake_up_locked(x)		__wake_up_locked((x), TASK_NORMAL)
+#define wake_up_locked(x)		__wake_up_locked((x), TASK_NORMAL, 1)
+#define wake_up_all_locked(x)		__wake_up_locked((x), TASK_NORMAL, 0)
 
 #define wake_up_interruptible(x)	__wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 #define wake_up_interruptible_nr(x, nr)	__wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 643cc37..820f745 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3418,9 +3418,9 @@ EXPORT_SYMBOL(__wake_up);
 /*
  * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
  */
-void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
+void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr)
 {
-	__wake_up_common(q, mode, 1, 0, NULL);
+	__wake_up_common(q, mode, nr, 0, NULL);
 }
 EXPORT_SYMBOL_GPL(__wake_up_locked);
 
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