[PATCH] kill sigqueue->lock

This lock is used in sigqueue_free(), but it is always equal to
current->sighand->siglock, so we don't need to keep it in the struct
sigqueue.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 4 insertions, 7 deletions

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 7be18b5e2fb4..5dd5f02c5c5f 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -25,7 +25,6 @@
 
 struct sigqueue {
         struct list_head list;
-        spinlock_t *lock;
         int flags;
         siginfo_t info;
         struct user_struct *user;
diff --git a/kernel/signal.c b/kernel/signal.c
index 6904bbbfe116..8d6e64dfa5c6 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -277,7 +277,6 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
         } else {
                 INIT_LIST_HEAD(&q->list);
                 q->flags = 0;
-                q->lock = NULL;
                 q->user = get_uid(t->user);
         }
         return(q);
@@ -1371,11 +1370,12 @@ void sigqueue_free(struct sigqueue *q)
          * pending queue.
          */
         if (unlikely(!list_empty(&q->list))) {
-                read_lock(&tasklist_lock);  
-                spin_lock_irqsave(q->lock, flags);
+                spinlock_t *lock = &current->sighand->siglock;
+                read_lock(&tasklist_lock);
+                spin_lock_irqsave(lock, flags);
                 if (!list_empty(&q->list))
                         list_del_init(&q->list);
-                spin_unlock_irqrestore(q->lock, flags);
+                spin_unlock_irqrestore(lock, flags);
                 read_unlock(&tasklist_lock);
         }
         q->flags &= ~SIGQUEUE_PREALLOC;
@@ -1414,7 +1414,6 @@ send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
                 goto out;
         }
 
-        q->lock = &p->sighand->siglock;
         list_add_tail(&q->list, &p->pending.list);
         sigaddset(&p->pending.signal, sig);
         if (!sigismember(&p->blocked, sig))
@@ -1462,7 +1461,6 @@ send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
          * We always use the shared queue for process-wide signals,
          * to avoid several races.
          */
-        q->lock = &p->sighand->siglock;
         list_add_tail(&q->list, &p->signal->shared_pending.list);
         sigaddset(&p->signal->shared_pending.signal, sig);