NFSv4: Callers to nfs4_get_renew_cred() need to hold nfs_client->cl_lock
[safe/jmp/linux-2.6] / kernel / posix-timers.c
index 57efe04..a140e44 100644 (file)
@@ -37,7 +37,6 @@
 #include <linux/mutex.h>
 
 #include <asm/uaccess.h>
-#include <asm/semaphore.h>
 #include <linux/list.h>
 #include <linux/init.h>
 #include <linux/compiler.h>
@@ -198,6 +197,11 @@ static int common_timer_create(struct k_itimer *new_timer)
        return 0;
 }
 
+static int no_timer_create(struct k_itimer *new_timer)
+{
+       return -EOPNOTSUPP;
+}
+
 /*
  * Return nonzero if we know a priori this clockid_t value is bogus.
  */
@@ -224,6 +228,15 @@ static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp)
 }
 
 /*
+ * Get monotonic time for posix timers
+ */
+static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp)
+{
+       getrawmonotonic(tp);
+       return 0;
+}
+
+/*
  * Initialize everything, well, just everything in Posix clocks/timers ;)
  */
 static __init int init_posix_timers(void)
@@ -236,12 +249,20 @@ static __init int init_posix_timers(void)
                .clock_get = posix_ktime_get_ts,
                .clock_set = do_posix_clock_nosettime,
        };
+       struct k_clock clock_monotonic_raw = {
+               .clock_getres = hrtimer_get_res,
+               .clock_get = posix_get_monotonic_raw,
+               .clock_set = do_posix_clock_nosettime,
+               .timer_create = no_timer_create,
+       };
 
        register_posix_clock(CLOCK_REALTIME, &clock_realtime);
        register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
+       register_posix_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
 
        posix_timers_cache = kmem_cache_create("posix_timers_cache",
-                                       sizeof (struct k_itimer), 0, 0, NULL);
+                                       sizeof (struct k_itimer), 0, SLAB_PANIC,
+                                       NULL);
        idr_init(&posix_timers_id);
        return 0;
 }
@@ -255,8 +276,9 @@ static void schedule_next_timer(struct k_itimer *timr)
        if (timr->it.real.interval.tv64 == 0)
                return;
 
-       timr->it_overrun += hrtimer_forward(timer, timer->base->get_time(),
-                                           timr->it.real.interval);
+       timr->it_overrun += (unsigned int) hrtimer_forward(timer,
+                                               timer->base->get_time(),
+                                               timr->it.real.interval);
 
        timr->it_overrun_last = timr->it_overrun;
        timr->it_overrun = -1;
@@ -288,41 +310,33 @@ void do_schedule_next_timer(struct siginfo *info)
                else
                        schedule_next_timer(timr);
 
-               info->si_overrun = timr->it_overrun_last;
+               info->si_overrun += timr->it_overrun_last;
        }
 
        if (timr)
                unlock_timer(timr, flags);
 }
 
-int posix_timer_event(struct k_itimer *timr,int si_private)
+int posix_timer_event(struct k_itimer *timr, int si_private)
 {
-       memset(&timr->sigq->info, 0, sizeof(siginfo_t));
+       int shared, ret;
+       /*
+        * FIXME: if ->sigq is queued we can race with
+        * dequeue_signal()->do_schedule_next_timer().
+        *
+        * If dequeue_signal() sees the "right" value of
+        * si_sys_private it calls do_schedule_next_timer().
+        * We re-queue ->sigq and drop ->it_lock().
+        * do_schedule_next_timer() locks the timer
+        * and re-schedules it while ->sigq is pending.
+        * Not really bad, but not that we want.
+        */
        timr->sigq->info.si_sys_private = si_private;
-       /* Send signal to the process that owns this timer.*/
-
-       timr->sigq->info.si_signo = timr->it_sigev_signo;
-       timr->sigq->info.si_errno = 0;
-       timr->sigq->info.si_code = SI_TIMER;
-       timr->sigq->info.si_tid = timr->it_id;
-       timr->sigq->info.si_value = timr->it_sigev_value;
-
-       if (timr->it_sigev_notify & SIGEV_THREAD_ID) {
-               struct task_struct *leader;
-               int ret = send_sigqueue(timr->it_sigev_signo, timr->sigq,
-                                       timr->it_process);
-
-               if (likely(ret >= 0))
-                       return ret;
-
-               timr->it_sigev_notify = SIGEV_SIGNAL;
-               leader = timr->it_process->group_leader;
-               put_task_struct(timr->it_process);
-               timr->it_process = leader;
-       }
 
-       return send_group_sigqueue(timr->it_sigev_signo, timr->sigq,
-                                  timr->it_process);
+       shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
+       ret = send_sigqueue(timr->sigq, timr->it_process, shared);
+       /* If we failed to send the signal the timer stops. */
+       return ret > 0;
 }
 EXPORT_SYMBOL_GPL(posix_timer_event);
 
@@ -385,7 +399,7 @@ static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
                                        now = ktime_add(now, kj);
                        }
 #endif
-                       timr->it_overrun +=
+                       timr->it_overrun += (unsigned int)
                                hrtimer_forward(timer, now,
                                                timr->it.real.interval);
                        ret = HRTIMER_RESTART;
@@ -402,8 +416,8 @@ static struct task_struct * good_sigevent(sigevent_t * event)
        struct task_struct *rtn = current->group_leader;
 
        if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
-               (!(rtn = find_task_by_pid(event->sigev_notify_thread_id)) ||
-                rtn->tgid != current->tgid ||
+               (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
+                !same_thread_group(rtn, current) ||
                 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
                return NULL;
 
@@ -434,8 +448,9 @@ static struct k_itimer * alloc_posix_timer(void)
                return tmr;
        if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
                kmem_cache_free(posix_timers_cache, tmr);
-               tmr = NULL;
+               return NULL;
        }
+       memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
        return tmr;
 }
 
@@ -450,9 +465,6 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
                spin_unlock_irqrestore(&idr_lock, flags);
        }
        sigqueue_free(tmr->sigq);
-       if (unlikely(tmr->it_process) &&
-           tmr->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-               put_task_struct(tmr->it_process);
        kmem_cache_free(posix_timers_cache, tmr);
 }
 
@@ -463,11 +475,9 @@ sys_timer_create(const clockid_t which_clock,
                 struct sigevent __user *timer_event_spec,
                 timer_t __user * created_timer_id)
 {
-       int error = 0;
-       struct k_itimer *new_timer = NULL;
-       int new_timer_id;
-       struct task_struct *process = NULL;
-       unsigned long flags;
+       struct k_itimer *new_timer;
+       int error, new_timer_id;
+       struct task_struct *process;
        sigevent_t event;
        int it_id_set = IT_ID_NOT_SET;
 
@@ -485,14 +495,13 @@ sys_timer_create(const clockid_t which_clock,
                goto out;
        }
        spin_lock_irq(&idr_lock);
-       error = idr_get_new(&posix_timers_id, (void *) new_timer,
-                           &new_timer_id);
+       error = idr_get_new(&posix_timers_id, new_timer, &new_timer_id);
        spin_unlock_irq(&idr_lock);
-       if (error == -EAGAIN)
-               goto retry;
-       else if (error) {
+       if (error) {
+               if (error == -EAGAIN)
+                       goto retry;
                /*
-                * Wierd looking, but we return EAGAIN if the IDR is
+                * Weird looking, but we return EAGAIN if the IDR is
                 * full (proper POSIX return value for this)
                 */
                error = -EAGAIN;
@@ -521,67 +530,43 @@ sys_timer_create(const clockid_t which_clock,
                        error = -EFAULT;
                        goto out;
                }
-               new_timer->it_sigev_notify = event.sigev_notify;
-               new_timer->it_sigev_signo = event.sigev_signo;
-               new_timer->it_sigev_value = event.sigev_value;
-
-               read_lock(&tasklist_lock);
-               if ((process = good_sigevent(&event))) {
-                       /*
-                        * We may be setting up this process for another
-                        * thread.  It may be exiting.  To catch this
-                        * case the we check the PF_EXITING flag.  If
-                        * the flag is not set, the siglock will catch
-                        * him before it is too late (in exit_itimers).
-                        *
-                        * The exec case is a bit more invloved but easy
-                        * to code.  If the process is in our thread
-                        * group (and it must be or we would not allow
-                        * it here) and is doing an exec, it will cause
-                        * us to be killed.  In this case it will wait
-                        * for us to die which means we can finish this
-                        * linkage with our last gasp. I.e. no code :)
-                        */
-                       spin_lock_irqsave(&process->sighand->siglock, flags);
-                       if (!(process->flags & PF_EXITING)) {
-                               new_timer->it_process = process;
-                               list_add(&new_timer->list,
-                                        &process->signal->posix_timers);
-                               if (new_timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                                       get_task_struct(process);
-                               spin_unlock_irqrestore(&process->sighand->siglock, flags);
-                       } else {
-                               spin_unlock_irqrestore(&process->sighand->siglock, flags);
-                               process = NULL;
-                       }
-               }
-               read_unlock(&tasklist_lock);
+               rcu_read_lock();
+               process = good_sigevent(&event);
+               if (process)
+                       get_task_struct(process);
+               rcu_read_unlock();
                if (!process) {
                        error = -EINVAL;
                        goto out;
                }
        } else {
-               new_timer->it_sigev_notify = SIGEV_SIGNAL;
-               new_timer->it_sigev_signo = SIGALRM;
-               new_timer->it_sigev_value.sival_int = new_timer->it_id;
+               event.sigev_notify = SIGEV_SIGNAL;
+               event.sigev_signo = SIGALRM;
+               event.sigev_value.sival_int = new_timer->it_id;
                process = current->group_leader;
-               spin_lock_irqsave(&process->sighand->siglock, flags);
-               new_timer->it_process = process;
-               list_add(&new_timer->list, &process->signal->posix_timers);
-               spin_unlock_irqrestore(&process->sighand->siglock, flags);
+               get_task_struct(process);
        }
 
+       new_timer->it_sigev_notify     = event.sigev_notify;
+       new_timer->sigq->info.si_signo = event.sigev_signo;
+       new_timer->sigq->info.si_value = event.sigev_value;
+       new_timer->sigq->info.si_tid   = new_timer->it_id;
+       new_timer->sigq->info.si_code  = SI_TIMER;
+
+       spin_lock_irq(&current->sighand->siglock);
+       new_timer->it_process = process;
+       list_add(&new_timer->list, &current->signal->posix_timers);
+       spin_unlock_irq(&current->sighand->siglock);
+
+       return 0;
        /*
         * In the case of the timer belonging to another task, after
         * the task is unlocked, the timer is owned by the other task
         * and may cease to exist at any time.  Don't use or modify
         * new_timer after the unlock call.
         */
-
 out:
-       if (error)
-               release_posix_timer(new_timer, it_id_set);
-
+       release_posix_timer(new_timer, it_id_set);
        return error;
 }
 
@@ -592,7 +577,7 @@ out:
  * the find to the timer lock.  To avoid a dead lock, the timer id MUST
  * be release with out holding the timer lock.
  */
-static struct k_itimer * lock_timer(timer_t timer_id, unsigned long *flags)
+static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags)
 {
        struct k_itimer *timr;
        /*
@@ -600,23 +585,20 @@ static struct k_itimer * lock_timer(timer_t timer_id, unsigned long *flags)
         * flags part over to the timer lock.  Must not let interrupts in
         * while we are moving the lock.
         */
-
        spin_lock_irqsave(&idr_lock, *flags);
-       timr = (struct k_itimer *) idr_find(&posix_timers_id, (int) timer_id);
+       timr = idr_find(&posix_timers_id, (int)timer_id);
        if (timr) {
                spin_lock(&timr->it_lock);
-
-               if ((timr->it_id != timer_id) || !(timr->it_process) ||
-                               timr->it_process->tgid != current->tgid) {
-                       spin_unlock(&timr->it_lock);
-                       spin_unlock_irqrestore(&idr_lock, *flags);
-                       timr = NULL;
-               } else
+               if (timr->it_process &&
+                   same_thread_group(timr->it_process, current)) {
                        spin_unlock(&idr_lock);
-       } else
-               spin_unlock_irqrestore(&idr_lock, *flags);
+                       return timr;
+               }
+               spin_unlock(&timr->it_lock);
+       }
+       spin_unlock_irqrestore(&idr_lock, *flags);
 
-       return timr;
+       return NULL;
 }
 
 /*
@@ -661,9 +643,9 @@ common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
         */
        if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
            (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
-               timr->it_overrun += hrtimer_forward(timer, now, iv);
+               timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
 
-       remaining = ktime_sub(timer->expires, now);
+       remaining = ktime_sub(hrtimer_get_expires(timer), now);
        /* Return 0 only, when the timer is expired and not pending */
        if (remaining.tv64 <= 0) {
                /*
@@ -757,7 +739,7 @@ common_timer_set(struct k_itimer *timr, int flags,
        hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
        timr->it.real.timer.function = posix_timer_fn;
 
-       timer->expires = timespec_to_ktime(new_setting->it_value);
+       hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));
 
        /* Convert interval */
        timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
@@ -765,13 +747,13 @@ common_timer_set(struct k_itimer *timr, int flags,
        /* SIGEV_NONE timers are not queued ! See common_timer_get */
        if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
                /* Setup correct expiry time for relative timers */
-               if (mode == HRTIMER_MODE_REL)
-                       timer->expires = ktime_add(timer->expires,
-                                                  timer->base->get_time());
+               if (mode == HRTIMER_MODE_REL) {
+                       hrtimer_add_expires(timer, timer->base->get_time());
+               }
                return 0;
        }
 
-       hrtimer_start(timer, timer->expires, mode);
+       hrtimer_start_expires(timer, mode);
        return 0;
 }
 
@@ -855,11 +837,9 @@ retry_delete:
         * This keeps any tasks waiting on the spin lock from thinking
         * they got something (see the lock code above).
         */
-       if (timer->it_process) {
-               if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                       put_task_struct(timer->it_process);
-               timer->it_process = NULL;
-       }
+       put_task_struct(timer->it_process);
+       timer->it_process = NULL;
+
        unlock_timer(timer, flags);
        release_posix_timer(timer, IT_ID_SET);
        return 0;
@@ -884,11 +864,9 @@ retry_delete:
         * This keeps any tasks waiting on the spin lock from thinking
         * they got something (see the lock code above).
         */
-       if (timer->it_process) {
-               if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                       put_task_struct(timer->it_process);
-               timer->it_process = NULL;
-       }
+       put_task_struct(timer->it_process);
+       timer->it_process = NULL;
+
        unlock_timer(timer, flags);
        release_posix_timer(timer, IT_ID_SET);
 }