[PATCH] drop recursive migrate_disable in rt_write_trylock_irqsave

[Nicholas Mc Guire <der.herr@hofr.at>]

>From f13384c888660f34d5f888ca96e55ad46c3a27b6 Mon Sep 17 00:00:00 2001
From: Nicholas Mc Guire <der.herr@hofr.at>
Date: Thu, 21 Nov 2013 23:04:50 -0500
Subject: [PATCH] drop recursive migrate_disable in rt_write_trylock_irqsave

 rt_write_trylock_irqsave unconditionally calls rt_write_trylock which will
 disable migration if the lock was sucessfully acquired.
 This patch drops the recursive migrate_disable/enable in
 rt_write_trylock_irqsave and rt_write_unlock_irq respecttively

 No change of functionality

Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
---
 include/linux/rwlock_rt.h |    1 -
 kernel/rt.c               |    4 +---
 2 files changed, 1 insertions(+), 4 deletions(-)

diff --git a/include/linux/rwlock_rt.h b/include/linux/rwlock_rt.h
index 9a5fe26..f6c7612 100644
--- a/include/linux/rwlock_rt.h
+++ b/include/linux/rwlock_rt.h
@@ -105,7 +105,6 @@ extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key
 		typecheck(unsigned long, flags);	\
 		(void) flags;				\
 		rt_read_unlock(lock);			\
-		migrate_enable();			\
 	} while (0)
 
 #define write_unlock_irqrestore(lock, flags) \
diff --git a/kernel/rt.c b/kernel/rt.c
index 4b2c4a9..71d26a4 100644
--- a/kernel/rt.c
+++ b/kernel/rt.c
@@ -196,10 +196,8 @@ int __lockfunc rt_write_trylock_irqsave(rwlock_t *rwlock, unsigned long *flags)
 	int ret;
 
 	*flags = 0;
-	migrate_disable();
 	ret = rt_write_trylock(rwlock);
-	if (!ret)
-		migrate_enable();
+
 	return ret;
 }
 EXPORT_SYMBOL(rt_write_trylock_irqsave);
-- 
1.7.2.5