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| author | Thomas Gleixner <tglx@linutronix.de> | 2011-03-11 11:51:22 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-03-11 12:23:07 +0100 |
| commit | c0c9ed15042ceac7c485813012a0a97316101b57 (patch) | |
| tree | c89272252b44c8330854bee7291e81252d7715f5 /kernel/futex.c | |
| parent | 8fe8f545c6d753ead15e1f4919d39e8f9bb49629 (diff) | |
| download | lwn-c0c9ed15042ceac7c485813012a0a97316101b57.tar.gz lwn-c0c9ed15042ceac7c485813012a0a97316101b57.zip | |
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: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/futex.c')
| -rw-r--r-- | kernel/futex.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 3184d3b9cadf..773815465bac 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -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 @@ retry: * (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 @@ retry: /* * 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 @@ retry: */ 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 @@ retry: /* * 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 @@ retry: * 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 @@ retry: * 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; /* |