1 files changed, 82 insertions, 47 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index a8c7efc7a681..bc0ec674d3f4 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -29,6 +29,7 @@
 #include <linux/cpuset.h>
 #include <linux/syscalls.h>
 #include <linux/signal.h>
+#include <linux/posix-timers.h>
 #include <linux/cn_proc.h>
 #include <linux/mutex.h>
 #include <linux/futex.h>
@@ -50,15 +51,80 @@ static void __unhash_process(struct task_struct *p)
 {
         nr_threads--;
         detach_pid(p, PIDTYPE_PID);
-        detach_pid(p, PIDTYPE_TGID);
         if (thread_group_leader(p)) {
                 detach_pid(p, PIDTYPE_PGID);
                 detach_pid(p, PIDTYPE_SID);
-                if (p->pid)
-                        __get_cpu_var(process_counts)--;
+
+                list_del_init(&p->tasks);
+                __get_cpu_var(process_counts)--;
+        }
+        list_del_rcu(&p->thread_group);
+        remove_parent(p);
+}
+
+/*
+ * This function expects the tasklist_lock write-locked.
+ */
+static void __exit_signal(struct task_struct *tsk)
+{
+        struct signal_struct *sig = tsk->signal;
+        struct sighand_struct *sighand;
+
+        BUG_ON(!sig);
+        BUG_ON(!atomic_read(&sig->count));
+
+        rcu_read_lock();
+        sighand = rcu_dereference(tsk->sighand);
+        spin_lock(&sighand->siglock);
+
+        posix_cpu_timers_exit(tsk);
+        if (atomic_dec_and_test(&sig->count))
+                posix_cpu_timers_exit_group(tsk);
+        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) {
+                        wake_up_process(sig->group_exit_task);
+                        sig->group_exit_task = NULL;
+                }
+                if (tsk == sig->curr_target)
+                        sig->curr_target = next_thread(tsk);
+                /*
+                 * Accumulate here the counters for all threads but the
+                 * group leader as they die, so they can be added into
+                 * the process-wide totals when those are taken.
+                 * The group leader stays around as a zombie as long
+                 * as there are other threads.  When it gets reaped,
+                 * the exit.c code will add its counts into these totals.
+                 * We won't ever get here for the group leader, since it
+                 * will have been the last reference on the signal_struct.
+                 */
+                sig->utime = cputime_add(sig->utime, tsk->utime);
+                sig->stime = cputime_add(sig->stime, tsk->stime);
+                sig->min_flt += tsk->min_flt;
+                sig->maj_flt += tsk->maj_flt;
+                sig->nvcsw += tsk->nvcsw;
+                sig->nivcsw += tsk->nivcsw;
+                sig->sched_time += tsk->sched_time;
+                sig = NULL; /* Marker for below. */
         }
 
-        REMOVE_LINKS(p);
+        __unhash_process(tsk);
+
+        tsk->signal = NULL;
+        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) {
+                flush_sigqueue(&sig->shared_pending);
+                __cleanup_signal(sig);
+        }
 }
 
 void release_task(struct task_struct * p)
@@ -67,21 +133,14 @@ void release_task(struct task_struct * p)
         task_t *leader;
         struct dentry *proc_dentry;
 
-repeat: 
+repeat:
         atomic_dec(&p->user->processes);
         spin_lock(&p->proc_lock);
         proc_dentry = proc_pid_unhash(p);
         write_lock_irq(&tasklist_lock);
-        if (unlikely(p->ptrace))
-                __ptrace_unlink(p);
+        ptrace_unlink(p);
         BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
         __exit_signal(p);
-        /*
-         * Note that the fastpath in sys_times depends on __exit_signal having
-         * updated the counters before a task is removed from the tasklist of
-         * the process by __unhash_process.
-         */
-        __unhash_process(p);
 
         /*
          * If we are the last non-leader member of the thread
@@ -116,21 +175,6 @@ repeat:
                 goto repeat;
 }
 
-/* we are using it only for SMP init */
-
-void unhash_process(struct task_struct *p)
-{
-        struct dentry *proc_dentry;
-
-        spin_lock(&p->proc_lock);
-        proc_dentry = proc_pid_unhash(p);
-        write_lock_irq(&tasklist_lock);
-        __unhash_process(p);
-        write_unlock_irq(&tasklist_lock);
-        spin_unlock(&p->proc_lock);
-        proc_pid_flush(proc_dentry);
-}
-
 /*
  * This checks not only the pgrp, but falls back on the pid if no
  * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
@@ -238,10 +282,10 @@ static void reparent_to_init(void)
 
         ptrace_unlink(current);
         /* Reparent to init */
-        REMOVE_LINKS(current);
+        remove_parent(current);
         current->parent = child_reaper;
         current->real_parent = child_reaper;
-        SET_LINKS(current);
+        add_parent(current);
 
         /* Set the exit signal to SIGCHLD so we signal init on exit */
         current->exit_signal = SIGCHLD;
@@ -538,13 +582,13 @@ static void exit_mm(struct task_struct * tsk)
         mmput(mm);
 }
 
-static inline void choose_new_parent(task_t *p, task_t *reaper, task_t *child_reaper)
+static inline void choose_new_parent(task_t *p, task_t *reaper)
 {
         /*
          * Make sure we're not reparenting to ourselves and that
          * the parent is not a zombie.
          */
-        BUG_ON(p == reaper || reaper->exit_state >= EXIT_ZOMBIE);
+        BUG_ON(p == reaper || reaper->exit_state);
         p->real_parent = reaper;
 }
 
@@ -569,9 +613,9 @@ static void reparent_thread(task_t *p, task_t *father, int traced)
                  * anyway, so let go of it.
                  */
                 p->ptrace = 0;
-                list_del_init(&p->sibling);
+                remove_parent(p);
                 p->parent = p->real_parent;
-                list_add_tail(&p->sibling, &p->parent->children);
+                add_parent(p);
 
                 /* If we'd notified the old parent about this child's death,
                  * also notify the new parent.
@@ -645,7 +689,7 @@ static void forget_original_parent(struct task_struct * father,
 
                 if (father == p->real_parent) {
                         /* reparent with a reaper, real father it's us */
-                        choose_new_parent(p, reaper, child_reaper);
+                        choose_new_parent(p, reaper);
                         reparent_thread(p, father, 0);
                 } else {
                         /* reparent ptraced task to its real parent */
@@ -666,7 +710,7 @@ static void forget_original_parent(struct task_struct * father,
         }
         list_for_each_safe(_p, _n, &father->ptrace_children) {
                 p = list_entry(_p,struct task_struct,ptrace_list);
-                choose_new_parent(p, reaper, child_reaper);
+                choose_new_parent(p, reaper);
                 reparent_thread(p, father, 1);
         }
 }
@@ -807,7 +851,7 @@ fastcall NORET_TYPE void do_exit(long code)
                 panic("Aiee, killing interrupt handler!");
         if (unlikely(!tsk->pid))
                 panic("Attempted to kill the idle task!");
-        if (unlikely(tsk->pid == 1))
+        if (unlikely(tsk == child_reaper))
                 panic("Attempted to kill init!");
 
         if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
@@ -920,13 +964,6 @@ asmlinkage long sys_exit(int error_code)
         do_exit((error_code&0xff)<<8);
 }
 
-task_t fastcall *next_thread(const task_t *p)
-{
-        return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID);
-}
-
-EXPORT_SYMBOL(next_thread);
-
 /*
  * Take down every thread in the group.  This is called by fatal signals
  * as well as by sys_exit_group (below).
@@ -941,7 +978,6 @@ do_group_exit(int exit_code)
         else if (!thread_group_empty(current)) {
                 struct signal_struct *const sig = current->signal;
                 struct sighand_struct *const sighand = current->sighand;
-                read_lock(&tasklist_lock);
                 spin_lock_irq(&sighand->siglock);
                 if (sig->flags & SIGNAL_GROUP_EXIT)
                         /* Another thread got here before we took the lock.  */
@@ -951,7 +987,6 @@ do_group_exit(int exit_code)
                         zap_other_threads(current);
                 }
                 spin_unlock_irq(&sighand->siglock);
-                read_unlock(&tasklist_lock);
         }
 
         do_exit(exit_code);
@@ -1281,7 +1316,7 @@ bail_ref:
 
         /* move to end of parent's list to avoid starvation */
         remove_parent(p);
-        add_parent(p, p->parent);
+        add_parent(p);
 
         write_unlock_irq(&tasklist_lock);