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Commit 36cf3b5c authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds
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FUTEX: Tidy up the code 



The recent PRIVATE and REQUEUE_PI changes to the futex code made it hard to
read.  Tidy it up.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0746aec3

kernel/futex.c

+66 −72
Original line number Diff line number Diff line
@@ -120,6 +120,24 @@ static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS]; 
/* Futex-fs vfsmount entry: */

static struct vfsmount *futex_mnt;



/*

 * Take mm->mmap_sem, when futex is shared

 */

static inline void futex_lock_mm(struct rw_semaphore *fshared)

{

	if (fshared)

		down_read(fshared);

}



/*

 * Release mm->mmap_sem, when the futex is shared

 */

static inline void futex_unlock_mm(struct rw_semaphore *fshared)

{

	if (fshared)

		up_read(fshared);

}



/*

 * We hash on the keys returned from get_futex_key (see below).

 */
@@ -287,7 +305,18 @@ void drop_futex_key_refs(union futex_key *key) 
}

EXPORT_SYMBOL_GPL(drop_futex_key_refs);



static inline int get_futex_value_locked(u32 *dest, u32 __user *from)

static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval)

{

	u32 curval;



	pagefault_disable();

	curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);

	pagefault_enable();



	return curval;

}



static int get_futex_value_locked(u32 *dest, u32 __user *from)

{

	int ret;
@@ -620,9 +649,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this) 


		newval = FUTEX_WAITERS | new_owner->pid;



		pagefault_disable();

		curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);

		pagefault_enable();

		curval = cmpxchg_futex_value_locked(uaddr, uval, newval);



		if (curval == -EFAULT)

			ret = -EFAULT;
@@ -659,9 +686,7 @@ static int unlock_futex_pi(u32 __user *uaddr, u32 uval) 
	 * There is no waiter, so we unlock the futex. The owner died

	 * bit has not to be preserved here. We are the owner:

	 */

	pagefault_disable();

	oldval = futex_atomic_cmpxchg_inatomic(uaddr, uval, 0);

	pagefault_enable();

	oldval = cmpxchg_futex_value_locked(uaddr, uval, 0);



	if (oldval == -EFAULT)

		return oldval;
@@ -700,8 +725,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared, 
	union futex_key key;

	int ret;



	if (fshared)

		down_read(fshared);

	futex_lock_mm(fshared);



	ret = get_futex_key(uaddr, fshared, &key);

	if (unlikely(ret != 0))
@@ -725,8 +749,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared, 


	spin_unlock(&hb->lock);

out:

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);

	return ret;

}
@@ -746,8 +769,7 @@ futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared, 
	int ret, op_ret, attempt = 0;



retryfull:

	if (fshared)

		down_read(fshared);

	futex_lock_mm(fshared);



	ret = get_futex_key(uaddr1, fshared, &key1);

	if (unlikely(ret != 0))
@@ -803,8 +825,7 @@ retry: 
		 * If we would have faulted, release mmap_sem,

		 * fault it in and start all over again.

		 */

		if (fshared)

			up_read(fshared);

		futex_unlock_mm(fshared);



		ret = get_user(dummy, uaddr2);

		if (ret)
@@ -841,8 +862,8 @@ retry: 
	if (hb1 != hb2)

		spin_unlock(&hb2->lock);

out:

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);



	return ret;

}
@@ -861,8 +882,7 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared, 
	int ret, drop_count = 0;



 retry:

	if (fshared)

		down_read(fshared);

	futex_lock_mm(fshared);



	ret = get_futex_key(uaddr1, fshared, &key1);

	if (unlikely(ret != 0))
@@ -890,8 +910,7 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared, 
			 * If we would have faulted, release mmap_sem, fault

			 * it in and start all over again.

			 */

			if (fshared)

				up_read(fshared);

			futex_unlock_mm(fshared);



			ret = get_user(curval, uaddr1);
@@ -944,8 +963,7 @@ out_unlock: 
		drop_futex_key_refs(&key1);



out:

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);

	return ret;

}
@@ -1113,10 +1131,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, 
	while (!ret) {

		newval = (uval & FUTEX_OWNER_DIED) | newtid;



		pagefault_disable();

		curval = futex_atomic_cmpxchg_inatomic(uaddr,

						       uval, newval);

		pagefault_enable();

		curval = cmpxchg_futex_value_locked(uaddr, uval, newval);



		if (curval == -EFAULT)

			ret = -EFAULT;
@@ -1134,6 +1149,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, 
#define ARG3_SHARED  1



static long futex_wait_restart(struct restart_block *restart);



static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,

		      u32 val, ktime_t *abs_time)

{
@@ -1148,8 +1164,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, 


	q.pi_state = NULL;

 retry:

	if (fshared)

		down_read(fshared);

	futex_lock_mm(fshared);



	ret = get_futex_key(uaddr, fshared, &q.key);

	if (unlikely(ret != 0))
@@ -1186,8 +1201,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, 
		 * If we would have faulted, release mmap_sem, fault it in and

		 * start all over again.

		 */

		if (fshared)

			up_read(fshared);

		futex_unlock_mm(fshared);



		ret = get_user(uval, uaddr);
@@ -1206,8 +1220,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, 
	 * Now the futex is queued and we have checked the data, we

	 * don't want to hold mmap_sem while we sleep.

	 */

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);



	/*

	 * There might have been scheduling since the queue_me(), as we
@@ -1285,8 +1298,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, 
	queue_unlock(&q, hb);



 out_release_sem:

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);

	return ret;

}
@@ -1333,8 +1345,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 


	q.pi_state = NULL;

 retry:

	if (fshared)

		down_read(fshared);

	futex_lock_mm(fshared);



	ret = get_futex_key(uaddr, fshared, &q.key);

	if (unlikely(ret != 0))
@@ -1353,9 +1364,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 
	 */

	newval = current->pid;



	pagefault_disable();

	curval = futex_atomic_cmpxchg_inatomic(uaddr, 0, newval);

	pagefault_enable();

	curval = cmpxchg_futex_value_locked(uaddr, 0, newval);



	if (unlikely(curval == -EFAULT))

		goto uaddr_faulted;
@@ -1398,9 +1407,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 
		lock_taken = 1;

	}



	pagefault_disable();

	curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);

	pagefault_enable();

	curval = cmpxchg_futex_value_locked(uaddr, uval, newval);



	if (unlikely(curval == -EFAULT))

		goto uaddr_faulted;
@@ -1428,8 +1435,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 
			 * exit to complete.

			 */

			queue_unlock(&q, hb);

			if (fshared)

				up_read(fshared);

			futex_unlock_mm(fshared);

			cond_resched();

			goto retry;
@@ -1465,8 +1471,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 
	 * Now the futex is queued and we have checked the data, we

	 * don't want to hold mmap_sem while we sleep.

	 */

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);



	WARN_ON(!q.pi_state);

	/*
@@ -1480,8 +1485,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 
		ret = ret ? 0 : -EWOULDBLOCK;

	}



	if (fshared)

		down_read(fshared);

	futex_lock_mm(fshared);

	spin_lock(q.lock_ptr);



	if (!ret) {
@@ -1518,8 +1522,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 


	/* Unqueue and drop the lock */

	unqueue_me_pi(&q);

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);



	return ret != -EINTR ? ret : -ERESTARTNOINTR;
@@ -1527,8 +1530,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 
	queue_unlock(&q, hb);



 out_release_sem:

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);

	return ret;



 uaddr_faulted:
@@ -1550,8 +1552,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, 
		goto retry_unlocked;

	}



	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);



	ret = get_user(uval, uaddr);

	if (!ret && (uval != -EFAULT))
@@ -1585,8 +1586,7 @@ retry: 
	/*

	 * First take all the futex related locks:

	 */

	if (fshared)

		down_read(fshared);

	futex_lock_mm(fshared);



	ret = get_futex_key(uaddr, fshared, &key);

	if (unlikely(ret != 0))
@@ -1601,11 +1601,9 @@ retry_unlocked: 
	 * again. If it succeeds then we can return without waking

	 * anyone else up:

	 */

	if (!(uval & FUTEX_OWNER_DIED)) {

		pagefault_disable();

		uval = futex_atomic_cmpxchg_inatomic(uaddr, current->pid, 0);

		pagefault_enable();

	}

	if (!(uval & FUTEX_OWNER_DIED))

		uval = cmpxchg_futex_value_locked(uaddr, current->pid, 0);





	if (unlikely(uval == -EFAULT))

		goto pi_faulted;
@@ -1647,8 +1645,7 @@ retry_unlocked: 
out_unlock:

	spin_unlock(&hb->lock);

out:

	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);



	return ret;
@@ -1671,8 +1668,7 @@ pi_faulted: 
		goto retry_unlocked;

	}



	if (fshared)

		up_read(fshared);

	futex_unlock_mm(fshared);



	ret = get_user(uval, uaddr);

	if (!ret && (uval != -EFAULT))
@@ -1908,11 +1904,9 @@ retry: 
		 * Wake robust non-PI futexes here. The wakeup of

		 * PI futexes happens in exit_pi_state():

		 */

		if (!pi) {

			if (uval & FUTEX_WAITERS)

		if (!pi && (uval & FUTEX_WAITERS))

				futex_wake(uaddr, &curr->mm->mmap_sem, 1);

	}

	}

	return 0;

}

kernel/rtmutex-debug.c

+0 −6
Original line number Diff line number Diff line
@@ -29,12 +29,6 @@ 


#include "rtmutex_common.h"



#ifdef CONFIG_DEBUG_RT_MUTEXES

# include "rtmutex-debug.h"

#else

# include "rtmutex.h"

#endif



# define TRACE_WARN_ON(x)			WARN_ON(x)

# define TRACE_BUG_ON(x)			BUG_ON(x)

kernel/rtmutex.c

+0 −6
Original line number Diff line number Diff line
@@ -17,12 +17,6 @@ 


#include "rtmutex_common.h"



#ifdef CONFIG_DEBUG_RT_MUTEXES

# include "rtmutex-debug.h"

#else

# include "rtmutex.h"

#endif



/*

 * lock->owner state tracking:

 *

kernel/rtmutex_common.h

+8 −1
Original line number Diff line number Diff line
@@ -120,4 +120,11 @@ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock, 
				       struct task_struct *proxy_owner);

extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,

				  struct task_struct *proxy_owner);



#ifdef CONFIG_DEBUG_RT_MUTEXES

# include "rtmutex-debug.h"

#else

# include "rtmutex.h"

#endif



#endif