Commit-ID: c0c9ed15042ceac7c485813012a0a97316101b57
Gitweb: http://git.kernel.org/tip/c0c9ed15042ceac7c485813012a0a97316101b57
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Fri, 11 Mar 2011 11:51:22 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Fri, 11 Mar 2011 12:23:07 +0100
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@xxxxxxxxxxxxx>
---
kernel/futex.c | 16 ++++++++--------
1 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index 3184d3b..7738154 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;
/*
--
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