Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuil...

[linux-2.6-microblaze.git] / kernel / posix-cpu-timers.c

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 9829646..05bb717 100644 (file)
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -16,13 +16,13 @@
  * siglock protection since other code may update expiration cache as
  * well.
  */
-void update_rlimit_cpu(unsigned long rlim_new)
+void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
 {
        cputime_t cputime = secs_to_cputime(rlim_new);
 
-       spin_lock_irq(&current->sighand->siglock);
-       set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
-       spin_unlock_irq(&current->sighand->siglock);
+       spin_lock_irq(&task->sighand->siglock);
+       set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
+       spin_unlock_irq(&task->sighand->siglock);
 }
 
 static int check_clock(const clockid_t which_clock)
@@ -37,13 +37,13 @@ static int check_clock(const clockid_t which_clock)
        if (pid == 0)
                return 0;
 
-       read_lock(&tasklist_lock);
+       rcu_read_lock();
        p = find_task_by_vpid(pid);
        if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
-                  same_thread_group(p, current) : thread_group_leader(p))) {
+                  same_thread_group(p, current) : has_group_leader_pid(p))) {
                error = -EINVAL;
        }
-       read_unlock(&tasklist_lock);
+       rcu_read_unlock();
 
        return error;
 }
@@ -232,31 +232,24 @@ static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
 
 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
 {
-       struct sighand_struct *sighand;
-       struct signal_struct *sig;
+       struct signal_struct *sig = tsk->signal;
        struct task_struct *t;
 
-       *times = INIT_CPUTIME;
+       times->utime = sig->utime;
+       times->stime = sig->stime;
+       times->sum_exec_runtime = sig->sum_sched_runtime;
 
        rcu_read_lock();
-       sighand = rcu_dereference(tsk->sighand);
-       if (!sighand)
+       /* make sure we can trust tsk->thread_group list */
+       if (!likely(pid_alive(tsk)))
                goto out;
 
-       sig = tsk->signal;
-
        t = tsk;
        do {
                times->utime = cputime_add(times->utime, t->utime);
                times->stime = cputime_add(times->stime, t->stime);
                times->sum_exec_runtime += t->se.sum_exec_runtime;
-
-               t = next_thread(t);
-       } while (t != tsk);
-
-       times->utime = cputime_add(times->utime, sig->utime);
-       times->stime = cputime_add(times->stime, sig->stime);
-       times->sum_exec_runtime += sig->sum_sched_runtime;
+       } while_each_thread(tsk, t);
 out:
        rcu_read_unlock();
 }
@@ -397,7 +390,7 @@ int posix_cpu_timer_create(struct k_itimer *new_timer)
 
        INIT_LIST_HEAD(&new_timer->it.cpu.entry);
 
-       read_lock(&tasklist_lock);
+       rcu_read_lock();
        if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
                if (pid == 0) {
                        p = current;
@@ -411,7 +404,7 @@ int posix_cpu_timer_create(struct k_itimer *new_timer)
                        p = current->group_leader;
                } else {
                        p = find_task_by_vpid(pid);
-                       if (p && !thread_group_leader(p))
+                       if (p && !has_group_leader_pid(p))
                                p = NULL;
                }
        }
@@ -421,7 +414,7 @@ int posix_cpu_timer_create(struct k_itimer *new_timer)
        } else {
                ret = -EINVAL;
        }
-       read_unlock(&tasklist_lock);
+       rcu_read_unlock();
 
        return ret;
 }
@@ -1279,10 +1272,6 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
 {
        struct signal_struct *sig;
 
-       /* tsk == current, ensure it is safe to use ->signal/sighand */
-       if (unlikely(tsk->exit_state))
-               return 0;
-
        if (!task_cputime_zero(&tsk->cputime_expires)) {
                struct task_cputime task_sample = {
                        .utime = tsk->utime,
@@ -1298,7 +1287,10 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
        if (sig->cputimer.running) {
                struct task_cputime group_sample;
 
-               thread_group_cputimer(tsk, &group_sample);
+               spin_lock(&sig->cputimer.lock);
+               group_sample = sig->cputimer.cputime;
+               spin_unlock(&sig->cputimer.lock);
+
                if (task_cputime_expired(&group_sample, &sig->cputime_expires))
                        return 1;
        }
@@ -1315,6 +1307,7 @@ void run_posix_cpu_timers(struct task_struct *tsk)
 {
        LIST_HEAD(firing);
        struct k_itimer *timer, *next;
+       unsigned long flags;
 
        BUG_ON(!irqs_disabled());
 
@@ -1325,7 +1318,8 @@ void run_posix_cpu_timers(struct task_struct *tsk)
        if (!fastpath_timer_check(tsk))
                return;
 
-       spin_lock(&tsk->sighand->siglock);
+       if (!lock_task_sighand(tsk, &flags))
+               return;
        /*
         * Here we take off tsk->signal->cpu_timers[N] and
         * tsk->cpu_timers[N] all the timers that are firing, and
@@ -1347,7 +1341,7 @@ void run_posix_cpu_timers(struct task_struct *tsk)
         * that gets the timer lock before we do will give it up and
         * spin until we've taken care of that timer below.
         */
-       spin_unlock(&tsk->sighand->siglock);
+       unlock_task_sighand(tsk, &flags);
 
        /*
         * Now that all the timers on our list have the firing flag,