coredump: simplify core_state->nr_threads calculation

Change zap_process() to return int instead of incrementing
mm->core_state->nr_threads directly.  Change zap_threads() to set
mm->core_state only on success.

This patch restores the original size of .text, and more importantly now
->nr_threads is used in two places only.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/exec.c b/fs/exec.c
index 50de3aaff4d008921a62fb54ea4cc809babeb2d7..c74bb34eeeff032f1d45809bc2a736e15bbab8e2 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1502,9 +1502,10 @@ out:
        return ispipe;
 }
 
-static void zap_process(struct task_struct *start)
+static int zap_process(struct task_struct *start)
 {
        struct task_struct *t;
+       int nr = 0;
 
        start->signal->flags = SIGNAL_GROUP_EXIT;
        start->signal->group_stop_count = 0;
@@ -1512,31 +1513,33 @@ static void zap_process(struct task_struct *start)
        t = start;
        do {
                if (t != current && t->mm) {
-                       t->mm->core_state->nr_threads++;
                        sigaddset(&t->pending.signal, SIGKILL);
                        signal_wake_up(t, 1);
+                       nr++;
                }
        } while_each_thread(start, t);
+
+       return nr;
 }
 
 static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
-                               int exit_code)
+                               struct core_state *core_state, int exit_code)
 {
        struct task_struct *g, *p;
        unsigned long flags;
-       int err = -EAGAIN;
+       int nr = -EAGAIN;
 
        spin_lock_irq(&tsk->sighand->siglock);
        if (!signal_group_exit(tsk->signal)) {
+               mm->core_state = core_state;
                tsk->signal->group_exit_code = exit_code;
-               zap_process(tsk);
-               err = 0;
+               nr = zap_process(tsk);
        }
        spin_unlock_irq(&tsk->sighand->siglock);
-       if (err)
-               return err;
+       if (unlikely(nr < 0))
+               return nr;
 
-       if (atomic_read(&mm->mm_users) == mm->core_state->nr_threads + 1)
+       if (atomic_read(&mm->mm_users) == nr + 1)
                goto done;
        /*
         * We should find and kill all tasks which use this mm, and we should
@@ -1579,7 +1582,7 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
                        if (p->mm) {
                                if (unlikely(p->mm == mm)) {
                                        lock_task_sighand(p, &flags);
-                                       zap_process(p);
+                                       nr += zap_process(p);
                                        unlock_task_sighand(p, &flags);
                                }
                                break;
@@ -1588,7 +1591,8 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
        }
        rcu_read_unlock();
 done:
-       return mm->core_state->nr_threads;
+       core_state->nr_threads = nr;
+       return nr;
 }
 
 static int coredump_wait(int exit_code)
@@ -1601,12 +1605,7 @@ static int coredump_wait(int exit_code)
 
        init_completion(&mm->core_done);
        init_completion(&core_state.startup);
-       core_state.nr_threads = 0;
-       mm->core_state = &core_state;
-
-       core_waiters = zap_threads(tsk, mm, exit_code);
-       if (core_waiters < 0)
-               mm->core_state = NULL;
+       core_waiters = zap_threads(tsk, mm, &core_state, exit_code);
        up_write(&mm->mmap_sem);
 
        if (unlikely(core_waiters < 0))