proc: turn signal_struct->count into "int nr_threads"
[linux-2.6.git] / kernel / exit.c
index 7f2683a..ceffc67 100644 (file)
 #include <asm/unistd.h>
 #include <asm/pgtable.h>
 #include <asm/mmu_context.h>
-#include "cred-internals.h"
 
 static void exit_mm(struct task_struct * tsk);
 
-static void __unhash_process(struct task_struct *p)
+static void __unhash_process(struct task_struct *p, bool group_dead)
 {
        nr_threads--;
        detach_pid(p, PIDTYPE_PID);
-       if (thread_group_leader(p)) {
+       if (group_dead) {
                detach_pid(p, PIDTYPE_PGID);
                detach_pid(p, PIDTYPE_SID);
 
@@ -80,10 +79,9 @@ static void __unhash_process(struct task_struct *p)
 static void __exit_signal(struct task_struct *tsk)
 {
        struct signal_struct *sig = tsk->signal;
+       bool group_dead = thread_group_leader(tsk);
        struct sighand_struct *sighand;
-
-       BUG_ON(!sig);
-       BUG_ON(!atomic_read(&sig->count));
+       struct tty_struct *uninitialized_var(tty);
 
        sighand = rcu_dereference_check(tsk->sighand,
                                        rcu_read_lock_held() ||
@@ -91,14 +89,16 @@ static void __exit_signal(struct task_struct *tsk)
        spin_lock(&sighand->siglock);
 
        posix_cpu_timers_exit(tsk);
-       if (atomic_dec_and_test(&sig->count))
+       if (group_dead) {
                posix_cpu_timers_exit_group(tsk);
-       else {
+               tty = sig->tty;
+               sig->tty = NULL;
+       } else {
                /*
                 * If there is any task waiting for the group exit
                 * then notify it:
                 */
-               if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count)
+               if (sig->notify_count > 0 && !--sig->notify_count)
                        wake_up_process(sig->group_exit_task);
 
                if (tsk == sig->curr_target)
@@ -124,32 +124,24 @@ static void __exit_signal(struct task_struct *tsk)
                sig->oublock += task_io_get_oublock(tsk);
                task_io_accounting_add(&sig->ioac, &tsk->ioac);
                sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
-               sig = NULL; /* Marker for below. */
        }
 
-       __unhash_process(tsk);
+       sig->nr_threads--;
+       __unhash_process(tsk, group_dead);
 
        /*
         * Do this under ->siglock, we can race with another thread
         * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
         */
        flush_sigqueue(&tsk->pending);
-
-       tsk->signal = NULL;
        tsk->sighand = NULL;
        spin_unlock(&sighand->siglock);
 
        __cleanup_sighand(sighand);
        clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
-       if (sig) {
+       if (group_dead) {
                flush_sigqueue(&sig->shared_pending);
-               taskstats_tgid_free(sig);
-               /*
-                * Make sure ->signal can't go away under rq->lock,
-                * see account_group_exec_runtime().
-                */
-               task_rq_unlock_wait(tsk);
-               __cleanup_signal(sig);
+               tty_kref_put(tty);
        }
 }
 
@@ -857,12 +849,9 @@ static void exit_notify(struct task_struct *tsk, int group_dead)
 
        tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE;
 
-       /* mt-exec, de_thread() is waiting for us */
-       if (thread_group_leader(tsk) &&
-           tsk->signal->group_exit_task &&
-           tsk->signal->notify_count < 0)
+       /* mt-exec, de_thread() is waiting for group leader */
+       if (unlikely(tsk->signal->notify_count < 0))
                wake_up_process(tsk->signal->group_exit_task);
-
        write_unlock_irq(&tasklist_lock);
 
        tracehook_report_death(tsk, signal, cookie, group_dead);
@@ -1003,8 +992,10 @@ NORET_TYPE void do_exit(long code)
 
        exit_notify(tsk, group_dead);
 #ifdef CONFIG_NUMA
+       task_lock(tsk);
        mpol_put(tsk->mempolicy);
        tsk->mempolicy = NULL;
+       task_unlock(tsk);
 #endif
 #ifdef CONFIG_FUTEX
        if (unlikely(current->pi_state_cache))