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authorOleg Nesterov <oleg@redhat.com>2010-05-26 14:43:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-27 09:12:46 -0700
commitd344193a05da89c97e965da2c5cbf687d7385eae (patch)
tree6267b68c31c4547f1749acd35d2a5bfaff919839 /fs/exec.c
parent09faef11df8c559a23e2405d123cb2683733a79a (diff)
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exit: avoid sig->count in de_thread/__exit_signal synchronization
de_thread() and __exit_signal() use signal_struct->count/notify_count for synchronization. We can simplify the code and use ->notify_count only. Instead of comparing these two counters, we can change de_thread() to set ->notify_count = nr_of_sub_threads, then change __exit_signal() to dec-and-test this counter and notify group_exit_task. Note that __exit_signal() checks "notify_count > 0" just for symmetry with exit_notify(), we could just check it is != 0. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 0c72d23ed0e..e19de6a8033 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -768,7 +768,6 @@ static int de_thread(struct task_struct *tsk)
struct signal_struct *sig = tsk->signal;
struct sighand_struct *oldsighand = tsk->sighand;
spinlock_t *lock = &oldsighand->siglock;
- int count;
if (thread_group_empty(tsk))
goto no_thread_group;
@@ -785,13 +784,13 @@ static int de_thread(struct task_struct *tsk)
spin_unlock_irq(lock);
return -EAGAIN;
}
+
sig->group_exit_task = tsk;
- zap_other_threads(tsk);
+ sig->notify_count = zap_other_threads(tsk);
+ if (!thread_group_leader(tsk))
+ sig->notify_count--;
- /* Account for the thread group leader hanging around: */
- count = thread_group_leader(tsk) ? 1 : 2;
- sig->notify_count = count;
- while (atomic_read(&sig->count) > count) {
+ while (sig->notify_count) {
__set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock_irq(lock);
schedule();