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Commit c0c9ed15 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

futex: Avoid redudant evaluation of task_pid_vnr() 



The result is not going to change under us, so no need to reevaluate
this over and over. Seems to be a leftover from the mechanical mass
conversion of task->pid to task_pid_vnr(tsk).

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 8fe8f545

kernel/futex.c

+8 −8
Original line number Diff line number Diff line
@@ -674,7 +674,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb, 
				struct task_struct *task, int set_waiters)

{

	int lock_taken, ret, ownerdied = 0;

	u32 uval, newval, curval;

	u32 uval, newval, curval, vpid = task_pid_vnr(task);



retry:

	ret = lock_taken = 0;
@@ -684,7 +684,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb, 
	 * (by doing a 0 -> TID atomic cmpxchg), while holding all

	 * the locks. It will most likely not succeed.

	 */

	newval = task_pid_vnr(task);

	newval = vpid;

	if (set_waiters)

		newval |= FUTEX_WAITERS;
@@ -696,7 +696,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb, 
	/*

	 * Detect deadlocks.

	 */

	if ((unlikely((curval & FUTEX_TID_MASK) == task_pid_vnr(task))))

	if ((unlikely((curval & FUTEX_TID_MASK) == vpid)))

		return -EDEADLK;



	/*
@@ -723,7 +723,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb, 
	 */

	if (unlikely(ownerdied || !(curval & FUTEX_TID_MASK))) {

		/* Keep the OWNER_DIED bit */

		newval = (curval & ~FUTEX_TID_MASK) | task_pid_vnr(task);

		newval = (curval & ~FUTEX_TID_MASK) | vpid;

		ownerdied = 0;

		lock_taken = 1;

	}
@@ -2047,9 +2047,9 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags) 
{

	struct futex_hash_bucket *hb;

	struct futex_q *this, *next;

	u32 uval;

	struct plist_head *head;

	union futex_key key = FUTEX_KEY_INIT;

	u32 uval, vpid = task_pid_vnr(current);

	int ret;



retry:
@@ -2058,7 +2058,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags) 
	/*

	 * We release only a lock we actually own:

	 */

	if ((uval & FUTEX_TID_MASK) != task_pid_vnr(current))

	if ((uval & FUTEX_TID_MASK) != vpid)

		return -EPERM;



	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key);
@@ -2074,7 +2074,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags) 
	 * anyone else up:

	 */

	if (!(uval & FUTEX_OWNER_DIED))

		uval = cmpxchg_futex_value_locked(uaddr, task_pid_vnr(current), 0);

		uval = cmpxchg_futex_value_locked(uaddr, vpid, 0);





	if (unlikely(uval == -EFAULT))
@@ -2083,7 +2083,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags) 
	 * Rare case: we managed to release the lock atomically,

	 * no need to wake anyone else up:

	 */

	if (unlikely(uval == task_pid_vnr(current)))

	if (unlikely(uval == vpid))

		goto out_unlock;



	/*