This patch moves the core mutex code over to the atomic helpers from
previous patch. There is no change for i386 and x86_64, except for the
forced unlock state that is now done outside the spinlock (with no
adverse effect).
At this point the patch adding asm-generic/atomic-call-if.h can probably
be dropped from the original mutex patch serie.
Signed-off-by: Nicolas Pitre <[email protected]>
---
Index: linux-2.6/kernel/mutex.c
===================================================================
--- linux-2.6.orig/kernel/mutex.c
+++ linux-2.6/kernel/mutex.c
@@ -296,14 +296,6 @@ static inline void __mutex_unlock_nonato
debug_mutex_unlock(lock);
- /*
- * Set it back to 'unlocked'. We'll have a waiter in flight
- * (if any), and if some other task comes around, let it
- * steal the lock. Waiters take care of themselves and stay
- * in flight until necessary.
- */
- atomic_set(&lock->count, 1);
-
if (!list_empty(&lock->wait_list))
mutex_wakeup_waiter(lock __IP__);
@@ -329,7 +321,7 @@ static __sched void FASTCALL(__mutex_loc
*/
static inline void __mutex_lock_atomic(struct mutex *lock)
{
- atomic_dec_call_if_negative(&lock->count, __mutex_lock_noinline);
+ arch_mutex_fast_lock(&lock->count, __mutex_lock_noinline);
}
static fastcall __sched void __mutex_lock_noinline(atomic_t *lock_count)
@@ -359,13 +351,19 @@ static void __sched FASTCALL(__mutex_unl
*/
static inline void __mutex_unlock_atomic(struct mutex *lock)
{
- atomic_inc_call_if_nonpositive(&lock->count, __mutex_unlock_noinline);
+ arch_mutex_fast_unlock(&lock->count, __mutex_unlock_noinline);
}
static fastcall void __sched __mutex_unlock_noinline(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
+ /*
+ * We were called via arch_mutex_fast_unlock() therefore
+ * we need to call arch_mutex_unlock_fixup() which will set
+ * the mutex to unlocked (but only if it wasn't done already).
+ */
+ arch_mutex_unlock_fixup(lock_count);
__mutex_unlock_nonatomic(lock);
}
@@ -383,6 +381,13 @@ static inline void __mutex_lock(struct m
static inline void __mutex_unlock(struct mutex *lock __IP_DECL__)
{
+ /*
+ * Set it back to 'unlocked'. We'll have a waiter in flight
+ * (if any), and if some other task comes around, let it
+ * steal the lock. Waiters take care of themselves and stay
+ * in flight until necessary.
+ */
+ atomic_set(&lock->count, 1);
__mutex_unlock_nonatomic(lock __IP__);
}
Index: linux-2.6/include/linux/mutex.h
===================================================================
--- linux-2.6.orig/include/linux/mutex.h
+++ linux-2.6/include/linux/mutex.h
@@ -14,6 +14,7 @@
#include <asm/atomic.h>
#include <linux/list.h>
#include <linux/spinlock_types.h>
+#include <asm/mutex.h>
/*
* Simple, straightforward mutexes with strict semantics:
-
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