Merge branch 'core/futexes' into core/core (cc37d3d2) · Commits · e / devices / android_kernel_sony_msm8998

include/linux/futex.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -25,7 +25,8 @@ union ktime;
		#define FUTEX_WAKE_BITSET 10

		#define FUTEX_PRIVATE_FLAG 128
		#define FUTEX_CMD_MASK ~FUTEX_PRIVATE_FLAG
		#define FUTEX_CLOCK_REALTIME 256
		#define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG \| FUTEX_CLOCK_REALTIME)

		#define FUTEX_WAIT_PRIVATE (FUTEX_WAIT \| FUTEX_PRIVATE_FLAG)
		#define FUTEX_WAKE_PRIVATE (FUTEX_WAKE \| FUTEX_PRIVATE_FLAG)

kernel/futex.c

+35 −26

Original line number	Diff line number	Diff line
		@@ -92,11 +92,12 @@ struct futex_pi_state {
		* A futex_q has a woken state, just like tasks have TASK_RUNNING.
		* It is considered woken when plist_node_empty(&q->list) \|\| q->lock_ptr == 0.
		* The order of wakup is always to make the first condition true, then
		* wake up q->waiters, then make the second condition true.
		* wake up q->waiter, then make the second condition true.
		*/
		struct futex_q {
		struct plist_node list;
		wait_queue_head_t waiters;
		/* There can only be a single waiter */
		wait_queue_head_t waiter;

		/* Which hash list lock to use: */
		spinlock_t *lock_ptr;
		@@ -573,7 +574,7 @@ static void wake_futex(struct futex_q *q)
		* The lock in wake_up_all() is a crucial memory barrier after the
		* plist_del() and also before assigning to q->lock_ptr.
		*/
		wake_up_all(&q->waiters);
		wake_up(&q->waiter);
		/*
		* The waiting task can free the futex_q as soon as this is written,
		* without taking any locks. This must come last.
		@@ -930,7 +931,7 @@ static inline struct futex_hash_bucket queue_lock(struct futex_q q)
		{
		struct futex_hash_bucket *hb;

		init_waitqueue_head(&q->waiters);
		init_waitqueue_head(&q->waiter);

		get_futex_key_refs(&q->key);
		hb = hash_futex(&q->key);
		@@ -1142,12 +1143,13 @@ handle_fault:
		* In case we must use restart_block to restart a futex_wait,
		* we encode in the 'flags' shared capability
		*/
		#define FLAGS_SHARED 1
		#define FLAGS_SHARED 0x01
		#define FLAGS_CLOCKRT 0x02

		static long futex_wait_restart(struct restart_block *restart);

		static int futex_wait(u32 __user *uaddr, int fshared,
		u32 val, ktime_t *abs_time, u32 bitset)
		u32 val, ktime_t *abs_time, u32 bitset, int clockrt)
		{
		struct task_struct *curr = current;
		DECLARE_WAITQUEUE(wait, curr);
		@@ -1220,7 +1222,7 @@ static int futex_wait(u32 __user *uaddr, int fshared,

		/* add_wait_queue is the barrier after __set_current_state. */
		__set_current_state(TASK_INTERRUPTIBLE);
		add_wait_queue(&q.waiters, &wait);
		add_wait_queue(&q.waiter, &wait);
		/*
		* !plist_node_empty() is safe here without any lock.
		* q.lock_ptr != 0 is not safe, because of ordering against wakeup.
		@@ -1233,7 +1235,9 @@ static int futex_wait(u32 __user *uaddr, int fshared,
		slack = current->timer_slack_ns;
		if (rt_task(current))
		slack = 0;
		hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC,
		hrtimer_init_on_stack(&t.timer,
		clockrt ? CLOCK_REALTIME :
		CLOCK_MONOTONIC,
		HRTIMER_MODE_ABS);
		hrtimer_init_sleeper(&t, current);
		hrtimer_set_expires_range_ns(&t.timer, *abs_time, slack);
		@@ -1289,6 +1293,8 @@ static int futex_wait(u32 __user *uaddr, int fshared,

		if (fshared)
		restart->futex.flags \|= FLAGS_SHARED;
		if (clockrt)
		restart->futex.flags \|= FLAGS_CLOCKRT;
		return -ERESTART_RESTARTBLOCK;
		}

		@@ -1312,7 +1318,8 @@ static long futex_wait_restart(struct restart_block *restart)
		if (restart->futex.flags & FLAGS_SHARED)
		fshared = 1;
		return (long)futex_wait(uaddr, fshared, restart->futex.val, &t,
		restart->futex.bitset);
		restart->futex.bitset,
		restart->futex.flags & FLAGS_CLOCKRT);
		}


		@@ -1558,12 +1565,11 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,

		uaddr_faulted:
		/*
		* We have to r/w (int __user )uaddr, but we can't modify it
		* non-atomically. Therefore, if get_user below is not
		* enough, we need to handle the fault ourselves, while
		* still holding the mmap_sem.
		*
		* ... and hb->lock. :-) --ANK
		* We have to r/w (int __user )uaddr, and we have to modify it
		* atomically. Therefore, if we continue to fault after get_user()
		* below, we need to handle the fault ourselves, while still holding
		* the mmap_sem. This can occur if the uaddr is under contention as
		* we have to drop the mmap_sem in order to call get_user().
		*/
		queue_unlock(&q, hb);

		@@ -1575,7 +1581,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
		}

		ret = get_user(uval, uaddr);
		if (!ret && (uval != -EFAULT))
		if (!ret)
		goto retry;

		if (to)
		@@ -1669,12 +1675,11 @@ out:

		pi_faulted:
		/*
		* We have to r/w (int __user )uaddr, but we can't modify it
		* non-atomically. Therefore, if get_user below is not
		* enough, we need to handle the fault ourselves, while
		* still holding the mmap_sem.
		*
		* ... and hb->lock. --ANK
		* We have to r/w (int __user )uaddr, and we have to modify it
		* atomically. Therefore, if we continue to fault after get_user()
		* below, we need to handle the fault ourselves, while still holding
		* the mmap_sem. This can occur if the uaddr is under contention as
		* we have to drop the mmap_sem in order to call get_user().
		*/
		spin_unlock(&hb->lock);

		@@ -1687,7 +1692,7 @@ pi_faulted:
		}

		ret = get_user(uval, uaddr);
		if (!ret && (uval != -EFAULT))
		if (!ret)
		goto retry;

		return ret;
		@@ -1905,18 +1910,22 @@ void exit_robust_list(struct task_struct *curr)
		long do_futex(u32 __user uaddr, int op, u32 val, ktime_t timeout,
		u32 __user *uaddr2, u32 val2, u32 val3)
		{
		int ret = -ENOSYS;
		int clockrt, ret = -ENOSYS;
		int cmd = op & FUTEX_CMD_MASK;
		int fshared = 0;

		if (!(op & FUTEX_PRIVATE_FLAG))
		fshared = 1;

		clockrt = op & FUTEX_CLOCK_REALTIME;
		if (clockrt && cmd != FUTEX_WAIT_BITSET)
		return -ENOSYS;

		switch (cmd) {
		case FUTEX_WAIT:
		val3 = FUTEX_BITSET_MATCH_ANY;
		case FUTEX_WAIT_BITSET:
		ret = futex_wait(uaddr, fshared, val, timeout, val3);
		ret = futex_wait(uaddr, fshared, val, timeout, val3, clockrt);
		break;
		case FUTEX_WAKE:
		val3 = FUTEX_BITSET_MATCH_ANY;