Ingo Oeser pointed out that because current expands to an inline function it
is more space efficient and somewhat faster to simply keep a cached copy of
current in another variable. This patch implements that for the de_thread
function.
Signed-off-by: Eric W. Biederman <[email protected]>
---
fs/exec.c | 46 +++++++++++++++++++++++-----------------------
1 files changed, 23 insertions(+), 23 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 1dd7d49..4dc39b7 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -597,7 +597,7 @@ static int de_thread(struct task_struct
if (!newsighand)
return -ENOMEM;
- if (thread_group_empty(current))
+ if (thread_group_empty(tsk))
goto no_thread_group;
/*
@@ -622,17 +622,17 @@ static int de_thread(struct task_struct
* Reparenting needs write_lock on tasklist_lock,
* so it is safe to do it under read_lock.
*/
- if (unlikely(current->group_leader == child_reaper))
- child_reaper = current;
+ if (unlikely(tsk->group_leader == child_reaper))
+ child_reaper = tsk;
- zap_other_threads(current);
+ zap_other_threads(tsk);
read_unlock(&tasklist_lock);
/*
* Account for the thread group leader hanging around:
*/
count = 1;
- if (!thread_group_leader(current)) {
+ if (!thread_group_leader(tsk)) {
count = 2;
/*
* The SIGALRM timer survives the exec, but needs to point
@@ -641,14 +641,14 @@ static int de_thread(struct task_struct
* synchronize with any firing (by calling del_timer_sync)
* before we can safely let the old group leader die.
*/
- sig->tsk = current;
+ sig->tsk = tsk;
spin_unlock_irq(lock);
if (hrtimer_cancel(&sig->real_timer))
hrtimer_restart(&sig->real_timer);
spin_lock_irq(lock);
}
while (atomic_read(&sig->count) > count) {
- sig->group_exit_task = current;
+ sig->group_exit_task = tsk;
sig->notify_count = count;
__set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock_irq(lock);
@@ -664,13 +664,13 @@ static int de_thread(struct task_struct
* do is to wait for the thread group leader to become inactive,
* and to assume its PID:
*/
- if (!thread_group_leader(current)) {
+ if (!thread_group_leader(tsk)) {
/*
* Wait for the thread group leader to be a zombie.
* It should already be zombie at this point, most
* of the time.
*/
- leader = current->group_leader;
+ leader = tsk->group_leader;
while (leader->exit_state != EXIT_ZOMBIE)
yield();
@@ -684,12 +684,12 @@ static int de_thread(struct task_struct
* When we take on its identity by switching to its PID, we
* also take its birthdate (always earlier than our own).
*/
- current->start_time = leader->start_time;
+ tsk->start_time = leader->start_time;
write_lock_irq(&tasklist_lock);
- BUG_ON(leader->tgid != current->tgid);
- BUG_ON(current->pid == current->tgid);
+ BUG_ON(leader->tgid != tsk->tgid);
+ BUG_ON(tsk->pid == tsk->tgid);
/*
* An exec() starts a new thread group with the
* TGID of the previous thread group. Rehash the
@@ -702,17 +702,17 @@ static int de_thread(struct task_struct
* Note: The old leader also uses this pid until release_task
* is called. Odd but simple and correct.
*/
- detach_pid(current, PIDTYPE_PID);
- current->pid = leader->pid;
- attach_pid(current, PIDTYPE_PID, current->pid);
- transfer_pid(leader, current, PIDTYPE_PGID);
- transfer_pid(leader, current, PIDTYPE_SID);
- list_replace_rcu(&leader->tasks, ¤t->tasks);
+ detach_pid(tsk, PIDTYPE_PID);
+ tsk->pid = leader->pid;
+ attach_pid(tsk, PIDTYPE_PID, tsk->pid);
+ transfer_pid(leader, tsk, PIDTYPE_PGID);
+ transfer_pid(leader, tsk, PIDTYPE_SID);
+ list_replace_rcu(&leader->tasks, &tsk->tasks);
- current->group_leader = current;
- leader->group_leader = current;
+ tsk->group_leader = tsk;
+ leader->group_leader = tsk;
- current->exit_signal = SIGCHLD;
+ tsk->exit_signal = SIGCHLD;
BUG_ON(leader->exit_state != EXIT_ZOMBIE);
leader->exit_state = EXIT_DEAD;
@@ -752,7 +752,7 @@ no_thread_group:
spin_lock(&oldsighand->siglock);
spin_lock(&newsighand->siglock);
- rcu_assign_pointer(current->sighand, newsighand);
+ rcu_assign_pointer(tsk->sighand, newsighand);
recalc_sigpending();
spin_unlock(&newsighand->siglock);
@@ -763,7 +763,7 @@ no_thread_group:
kmem_cache_free(sighand_cachep, oldsighand);
}
- BUG_ON(!thread_group_leader(current));
+ BUG_ON(!thread_group_leader(tsk));
return 0;
}
--
1.4.1.gac83a
-
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