Jetpack/kernel/kernel-4.9/rt-patches/0041-locking-percpu-rwsem-u...

81 lines
2.7 KiB
Diff

From 358e404240e79152accaa42383465c6ef2c62d7f Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Mon, 21 Nov 2016 19:26:15 +0100
Subject: [PATCH 041/352] locking/percpu-rwsem: use swait for the wating writer
Use struct swait_queue_head instead of wait_queue_head_t for the waiting
writer. The swait implementation is smaller and lightweight compared to
wait_queue_head_t.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
include/linux/percpu-rwsem.h | 6 +++---
kernel/locking/percpu-rwsem.c | 6 +++---
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 5b2e615..82d54a4 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -4,7 +4,7 @@
#include <linux/atomic.h>
#include <linux/rwsem.h>
#include <linux/percpu.h>
-#include <linux/wait.h>
+#include <linux/swait.h>
#include <linux/rcu_sync.h>
#include <linux/lockdep.h>
@@ -12,7 +12,7 @@ struct percpu_rw_semaphore {
struct rcu_sync rss;
unsigned int __percpu *read_count;
struct rw_semaphore rw_sem;
- wait_queue_head_t writer;
+ struct swait_queue_head writer;
int readers_block;
};
@@ -22,7 +22,7 @@ static struct percpu_rw_semaphore name = { \
.rss = __RCU_SYNC_INITIALIZER(name.rss, RCU_SCHED_SYNC), \
.read_count = &__percpu_rwsem_rc_##name, \
.rw_sem = __RWSEM_INITIALIZER(name.rw_sem), \
- .writer = __WAIT_QUEUE_HEAD_INITIALIZER(name.writer), \
+ .writer = __SWAIT_QUEUE_HEAD_INITIALIZER(name.writer), \
}
extern int __percpu_down_read(struct percpu_rw_semaphore *, int);
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index ce18259..2ad3a1e 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -18,7 +18,7 @@ int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
/* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */
rcu_sync_init(&sem->rss, RCU_SCHED_SYNC);
__init_rwsem(&sem->rw_sem, name, rwsem_key);
- init_waitqueue_head(&sem->writer);
+ init_swait_queue_head(&sem->writer);
sem->readers_block = 0;
return 0;
}
@@ -103,7 +103,7 @@ void __percpu_up_read(struct percpu_rw_semaphore *sem)
__this_cpu_dec(*sem->read_count);
/* Prod writer to recheck readers_active */
- wake_up(&sem->writer);
+ swake_up(&sem->writer);
}
EXPORT_SYMBOL_GPL(__percpu_up_read);
@@ -160,7 +160,7 @@ void percpu_down_write(struct percpu_rw_semaphore *sem)
*/
/* Wait for all now active readers to complete. */
- wait_event(sem->writer, readers_active_check(sem));
+ swait_event(sem->writer, readers_active_check(sem));
}
EXPORT_SYMBOL_GPL(percpu_down_write);
--
2.7.4