[PATCH] cleanup __exit_signal->cleanup_sighand path

Move 'tsk->sighand = NULL' from cleanup_sighand() to __exit_signal().  This
makes the exit path more understandable and allows us to do
cleanup_sighand() outside of ->siglock protected section.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
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/kernel/exit.c b/kernel/exit.c
index 22399caf7574..bc0ec674d3f4 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -114,10 +114,11 @@ static void __exit_signal(struct task_struct *tsk)
         __unhash_process(tsk);
 
         tsk->signal = NULL;
-        cleanup_sighand(tsk);
+        tsk->sighand = NULL;
         spin_unlock(&sighand->siglock);
         rcu_read_unlock();
 
+        __cleanup_sighand(sighand);
         clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
         flush_sigqueue(&tsk->pending);
         if (sig) {
diff --git a/kernel/fork.c b/kernel/fork.c
index aa50c848fae7..b3f7a1bb5e55 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -803,12 +803,8 @@ static inline int copy_sighand(unsigned long clone_flags, struct task_struct * t
         return 0;
 }
 
-void cleanup_sighand(struct task_struct *tsk)
+void __cleanup_sighand(struct sighand_struct *sighand)
 {
-        struct sighand_struct * sighand = tsk->sighand;
-
-        /* Ok, we're done with the signal handlers */
-        tsk->sighand = NULL;
         if (atomic_dec_and_test(&sighand->count))
                 kmem_cache_free(sighand_cachep, sighand);
 }
@@ -1233,7 +1229,7 @@ bad_fork_cleanup_mm:
 bad_fork_cleanup_signal:
         cleanup_signal(p);
 bad_fork_cleanup_sighand:
-        cleanup_sighand(p);
+        __cleanup_sighand(p->sighand);
 bad_fork_cleanup_fs:
         exit_fs(p); /* blocking */
 bad_fork_cleanup_files: