Clean up rwsems.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
spinlock_t wait_lock;
struct list_head wait_list;
-#if RWSEM_DEBUG
- int debug;
-#endif
};
-/*
- * initialisation
- */
-#if RWSEM_DEBUG
-#define __RWSEM_DEBUG_INIT , 0
-#else
-#define __RWSEM_DEBUG_INIT /* */
-#endif
-
#define __RWSEM_INITIALIZER(name) \
{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) \
- __RWSEM_DEBUG_INIT }
+ }
#define DECLARE_RWSEM(name) \
struct rw_semaphore name = __RWSEM_INITIALIZER(name)
sem->count = RWSEM_UNLOCKED_VALUE;
spin_lock_init(&sem->wait_lock);
INIT_LIST_HEAD(&sem->wait_list);
-#if RWSEM_DEBUG
- sem->debug = 0;
-#endif
}
/*
__s32 activity;
spinlock_t wait_lock;
struct list_head wait_list;
-#if RWSEM_DEBUG
- int debug;
-#endif
};
-/*
- * initialisation
- */
-#if RWSEM_DEBUG
-#define __RWSEM_DEBUG_INIT , 0
-#else
-#define __RWSEM_DEBUG_INIT /* */
-#endif
-
#define __RWSEM_INITIALIZER(name) \
-{ 0, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __RWSEM_DEBUG_INIT }
+{ 0, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) }
#define DECLARE_RWSEM(name) \
struct rw_semaphore name = __RWSEM_INITIALIZER(name)
#include <linux/linkage.h>
-#define RWSEM_DEBUG 0
-
#ifdef __KERNEL__
#include <linux/types.h>
#include <asm/rwsem.h> /* use an arch-specific implementation */
#endif
-#ifndef rwsemtrace
-#if RWSEM_DEBUG
-extern void FASTCALL(rwsemtrace(struct rw_semaphore *sem, const char *str));
-#else
-#define rwsemtrace(SEM,FMT)
-#endif
-#endif
-
/*
* lock for reading
*/
static inline void down_read(struct rw_semaphore *sem)
{
might_sleep();
- rwsemtrace(sem,"Entering down_read");
__down_read(sem);
- rwsemtrace(sem,"Leaving down_read");
}
/*
static inline int down_read_trylock(struct rw_semaphore *sem)
{
int ret;
- rwsemtrace(sem,"Entering down_read_trylock");
ret = __down_read_trylock(sem);
- rwsemtrace(sem,"Leaving down_read_trylock");
return ret;
}
static inline void down_write(struct rw_semaphore *sem)
{
might_sleep();
- rwsemtrace(sem,"Entering down_write");
__down_write(sem);
- rwsemtrace(sem,"Leaving down_write");
}
/*
static inline int down_write_trylock(struct rw_semaphore *sem)
{
int ret;
- rwsemtrace(sem,"Entering down_write_trylock");
ret = __down_write_trylock(sem);
- rwsemtrace(sem,"Leaving down_write_trylock");
return ret;
}
*/
static inline void up_read(struct rw_semaphore *sem)
{
- rwsemtrace(sem,"Entering up_read");
__up_read(sem);
- rwsemtrace(sem,"Leaving up_read");
}
/*
*/
static inline void up_write(struct rw_semaphore *sem)
{
- rwsemtrace(sem,"Entering up_write");
__up_write(sem);
- rwsemtrace(sem,"Leaving up_write");
}
/*
*/
static inline void downgrade_write(struct rw_semaphore *sem)
{
- rwsemtrace(sem,"Entering downgrade_write");
__downgrade_write(sem);
- rwsemtrace(sem,"Leaving downgrade_write");
}
#endif /* __KERNEL__ */
--- /dev/null
+/* kernel/rwsem.c: R/W semaphores, public implementation
+ *
+ * Written by David Howells (dhowells@redhat.com).
+ * Derived from asm-i386/semaphore.h
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rwsem.h>
+
+#include <asm/system.h>
+#include <asm/atomic.h>
+
+/*
+ * lock for reading
+ */
+void down_read(struct rw_semaphore *sem)
+{
+ might_sleep();
+ rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
+
+ __down_read(sem);
+}
+
+EXPORT_SYMBOL(down_read);
+
+/*
+ * trylock for reading -- returns 1 if successful, 0 if contention
+ */
+int down_read_trylock(struct rw_semaphore *sem)
+{
+ int ret = __down_read_trylock(sem);
+
+ if (ret == 1)
+ rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
+ return ret;
+}
+
+EXPORT_SYMBOL(down_read_trylock);
+
+/*
+ * lock for writing
+ */
+void down_write(struct rw_semaphore *sem)
+{
+ might_sleep();
+ rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+
+ __down_write(sem);
+}
+
+EXPORT_SYMBOL(down_write);
+
+/*
+ * trylock for writing -- returns 1 if successful, 0 if contention
+ */
+int down_write_trylock(struct rw_semaphore *sem)
+{
+ int ret = __down_write_trylock(sem);
+
+ if (ret == 1)
+ rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+ return ret;
+}
+
+EXPORT_SYMBOL(down_write_trylock);
+
+/*
+ * release a read lock
+ */
+void up_read(struct rw_semaphore *sem)
+{
+ rwsem_release(&sem->dep_map, 1, _RET_IP_);
+
+ __up_read(sem);
+}
+
+EXPORT_SYMBOL(up_read);
+
+/*
+ * release a write lock
+ */
+void up_write(struct rw_semaphore *sem)
+{
+ rwsem_release(&sem->dep_map, 1, _RET_IP_);
+
+ __up_write(sem);
+}
+
+EXPORT_SYMBOL(up_write);
+
+/*
+ * downgrade write lock to read lock
+ */
+void downgrade_write(struct rw_semaphore *sem)
+{
+ /*
+ * lockdep: a downgraded write will live on as a write
+ * dependency.
+ */
+ __downgrade_write(sem);
+}
+
+EXPORT_SYMBOL(downgrade_write);
#define RWSEM_WAITING_FOR_WRITE 0x00000002
};
-#if RWSEM_DEBUG
-void rwsemtrace(struct rw_semaphore *sem, const char *str)
-{
- if (sem->debug)
- printk("[%d] %s({%d,%d})\n",
- current->pid, str, sem->activity,
- list_empty(&sem->wait_list) ? 0 : 1);
-}
-#endif
-
/*
* initialise the semaphore
*/
sem->activity = 0;
spin_lock_init(&sem->wait_lock);
INIT_LIST_HEAD(&sem->wait_list);
-#if RWSEM_DEBUG
- sem->debug = 0;
-#endif
}
/*
struct task_struct *tsk;
int woken;
- rwsemtrace(sem, "Entering __rwsem_do_wake");
-
waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
if (!wakewrite) {
sem->activity += woken;
out:
- rwsemtrace(sem, "Leaving __rwsem_do_wake");
return sem;
}
struct rwsem_waiter waiter;
struct task_struct *tsk;
- rwsemtrace(sem, "Entering __down_read");
-
spin_lock_irq(&sem->wait_lock);
if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
}
tsk->state = TASK_RUNNING;
-
out:
- rwsemtrace(sem, "Leaving __down_read");
+ ;
}
/*
unsigned long flags;
int ret = 0;
- rwsemtrace(sem, "Entering __down_read_trylock");
spin_lock_irqsave(&sem->wait_lock, flags);
spin_unlock_irqrestore(&sem->wait_lock, flags);
- rwsemtrace(sem, "Leaving __down_read_trylock");
return ret;
}
struct rwsem_waiter waiter;
struct task_struct *tsk;
- rwsemtrace(sem, "Entering __down_write");
-
spin_lock_irq(&sem->wait_lock);
if (sem->activity == 0 && list_empty(&sem->wait_list)) {
}
tsk->state = TASK_RUNNING;
-
out:
- rwsemtrace(sem, "Leaving __down_write");
+ ;
}
/*
unsigned long flags;
int ret = 0;
- rwsemtrace(sem, "Entering __down_write_trylock");
-
spin_lock_irqsave(&sem->wait_lock, flags);
if (sem->activity == 0 && list_empty(&sem->wait_list)) {
spin_unlock_irqrestore(&sem->wait_lock, flags);
- rwsemtrace(sem, "Leaving __down_write_trylock");
return ret;
}
{
unsigned long flags;
- rwsemtrace(sem, "Entering __up_read");
-
spin_lock_irqsave(&sem->wait_lock, flags);
if (--sem->activity == 0 && !list_empty(&sem->wait_list))
sem = __rwsem_wake_one_writer(sem);
spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- rwsemtrace(sem, "Leaving __up_read");
}
/*
{
unsigned long flags;
- rwsemtrace(sem, "Entering __up_write");
-
spin_lock_irqsave(&sem->wait_lock, flags);
sem->activity = 0;
sem = __rwsem_do_wake(sem, 1);
spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- rwsemtrace(sem, "Leaving __up_write");
}
/*
{
unsigned long flags;
- rwsemtrace(sem, "Entering __downgrade_write");
-
spin_lock_irqsave(&sem->wait_lock, flags);
sem->activity = 1;
sem = __rwsem_do_wake(sem, 0);
spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- rwsemtrace(sem, "Leaving __downgrade_write");
}
EXPORT_SYMBOL(init_rwsem);
EXPORT_SYMBOL(__up_read);
EXPORT_SYMBOL(__up_write);
EXPORT_SYMBOL(__downgrade_write);
-#if RWSEM_DEBUG
-EXPORT_SYMBOL(rwsemtrace);
-#endif
#define RWSEM_WAITING_FOR_WRITE 0x00000002
};
-#if RWSEM_DEBUG
-#undef rwsemtrace
-void rwsemtrace(struct rw_semaphore *sem, const char *str)
-{
- printk("sem=%p\n", sem);
- printk("(sem)=%08lx\n", sem->count);
- if (sem->debug)
- printk("[%d] %s({%08lx})\n", current->pid, str, sem->count);
-}
-#endif
-
/*
* handle the lock release when processes blocked on it that can now run
* - if we come here from up_xxxx(), then:
struct list_head *next;
signed long oldcount, woken, loop;
- rwsemtrace(sem, "Entering __rwsem_do_wake");
-
if (downgrading)
goto dont_wake_writers;
next->prev = &sem->wait_list;
out:
- rwsemtrace(sem, "Leaving __rwsem_do_wake");
return sem;
/* undo the change to count, but check for a transition 1->0 */
{
struct rwsem_waiter waiter;
- rwsemtrace(sem, "Entering rwsem_down_read_failed");
-
waiter.flags = RWSEM_WAITING_FOR_READ;
rwsem_down_failed_common(sem, &waiter,
RWSEM_WAITING_BIAS - RWSEM_ACTIVE_BIAS);
-
- rwsemtrace(sem, "Leaving rwsem_down_read_failed");
return sem;
}
{
struct rwsem_waiter waiter;
- rwsemtrace(sem, "Entering rwsem_down_write_failed");
-
waiter.flags = RWSEM_WAITING_FOR_WRITE;
rwsem_down_failed_common(sem, &waiter, -RWSEM_ACTIVE_BIAS);
- rwsemtrace(sem, "Leaving rwsem_down_write_failed");
return sem;
}
{
unsigned long flags;
- rwsemtrace(sem, "Entering rwsem_wake");
-
spin_lock_irqsave(&sem->wait_lock, flags);
/* do nothing if list empty */
spin_unlock_irqrestore(&sem->wait_lock, flags);
- rwsemtrace(sem, "Leaving rwsem_wake");
-
return sem;
}
{
unsigned long flags;
- rwsemtrace(sem, "Entering rwsem_downgrade_wake");
-
spin_lock_irqsave(&sem->wait_lock, flags);
/* do nothing if list empty */
spin_unlock_irqrestore(&sem->wait_lock, flags);
- rwsemtrace(sem, "Leaving rwsem_downgrade_wake");
return sem;
}
EXPORT_SYMBOL(rwsem_down_write_failed);
EXPORT_SYMBOL(rwsem_wake);
EXPORT_SYMBOL(rwsem_downgrade_wake);
-#if RWSEM_DEBUG
-EXPORT_SYMBOL(rwsemtrace);
-#endif
projects / linux-2.6 / commitdiff