Merge /home/trondmy/scm/kernel/git/torvalds/linux-2.6

1 files changed, 63 insertions, 47 deletions

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index b3f3edc475de..bf374fceb39c 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -91,7 +91,7 @@ static inline union cpu_time_count cpu_time_sub(clockid_t which_clock,
  * Update expiry time from increment, and increase overrun count,
  * given the current clock sample.
  */
-static inline void bump_cpu_timer(struct k_itimer *timer,
+static void bump_cpu_timer(struct k_itimer *timer,
                                   union cpu_time_count now)
 {
         int i;
@@ -110,7 +110,7 @@ static inline void bump_cpu_timer(struct k_itimer *timer,
                 for (i = 0; incr < delta - incr; i++)
                         incr = incr << 1;
                 for (; i >= 0; incr >>= 1, i--) {
-                        if (delta <= incr)
+                        if (delta < incr)
                                 continue;
                         timer->it.cpu.expires.sched += incr;
                         timer->it_overrun += 1 << i;
@@ -128,7 +128,7 @@ static inline void bump_cpu_timer(struct k_itimer *timer,
                 for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
                              incr = cputime_add(incr, incr);
                 for (; i >= 0; incr = cputime_halve(incr), i--) {
-                        if (cputime_le(delta, incr))
+                        if (cputime_lt(delta, incr))
                                 continue;
                         timer->it.cpu.expires.cpu =
                                 cputime_add(timer->it.cpu.expires.cpu, incr);
@@ -380,28 +380,31 @@ int posix_cpu_timer_create(struct k_itimer *new_timer)
 int posix_cpu_timer_del(struct k_itimer *timer)
 {
         struct task_struct *p = timer->it.cpu.task;
+        int ret = 0;
 
-        if (timer->it.cpu.firing)
-                return TIMER_RETRY;
-
-        if (unlikely(p == NULL))
-                return 0;
+        if (likely(p != NULL)) {
+                read_lock(&tasklist_lock);
+                if (unlikely(p->signal == NULL)) {
+                        /*
+                         * We raced with the reaping of the task.
+                         * The deletion should have cleared us off the list.
+                         */
+                        BUG_ON(!list_empty(&timer->it.cpu.entry));
+                } else {
+                        spin_lock(&p->sighand->siglock);
+                        if (timer->it.cpu.firing)
+                                ret = TIMER_RETRY;
+                        else
+                                list_del(&timer->it.cpu.entry);
+                        spin_unlock(&p->sighand->siglock);
+                }
+                read_unlock(&tasklist_lock);
 
-        spin_lock(&p->sighand->siglock);
-        if (!list_empty(&timer->it.cpu.entry)) {
-                /*
-                 * Take us off the task's timer list.  We don't need to
-                 * take tasklist_lock and check for the task being reaped.
-                 * If it was reaped, it already called posix_cpu_timers_exit
-                 * and posix_cpu_timers_exit_group to clear all the timers
-                 * that pointed to it.
-                 */
-                list_del(&timer->it.cpu.entry);
-                put_task_struct(p);
+                if (!ret)
+                        put_task_struct(p);
         }
-        spin_unlock(&p->sighand->siglock);
 
-        return 0;
+        return ret;
 }
 
 /*
@@ -418,8 +421,6 @@ static void cleanup_timers(struct list_head *head,
         cputime_t ptime = cputime_add(utime, stime);
 
         list_for_each_entry_safe(timer, next, head, entry) {
-                put_task_struct(timer->task);
-                timer->task = NULL;
                 list_del_init(&timer->entry);
                 if (cputime_lt(timer->expires.cpu, ptime)) {
                         timer->expires.cpu = cputime_zero;
@@ -431,8 +432,6 @@ static void cleanup_timers(struct list_head *head,
 
         ++head;
         list_for_each_entry_safe(timer, next, head, entry) {
-                put_task_struct(timer->task);
-                timer->task = NULL;
                 list_del_init(&timer->entry);
                 if (cputime_lt(timer->expires.cpu, utime)) {
                         timer->expires.cpu = cputime_zero;
@@ -444,8 +443,6 @@ static void cleanup_timers(struct list_head *head,
 
         ++head;
         list_for_each_entry_safe(timer, next, head, entry) {
-                put_task_struct(timer->task);
-                timer->task = NULL;
                 list_del_init(&timer->entry);
                 if (timer->expires.sched < sched_time) {
                         timer->expires.sched = 0;
@@ -489,6 +486,9 @@ static void process_timer_rebalance(struct task_struct *p,
         struct task_struct *t = p;
         unsigned int nthreads = atomic_read(&p->signal->live);
 
+        if (!nthreads)
+                return;
+
         switch (clock_idx) {
         default:
                 BUG();
@@ -497,7 +497,7 @@ static void process_timer_rebalance(struct task_struct *p,
                 left = cputime_div(cputime_sub(expires.cpu, val.cpu),
                                    nthreads);
                 do {
-                        if (!unlikely(t->exit_state)) {
+                        if (!unlikely(t->flags & PF_EXITING)) {
                                 ticks = cputime_add(prof_ticks(t), left);
                                 if (cputime_eq(t->it_prof_expires,
                                                cputime_zero) ||
@@ -512,7 +512,7 @@ static void process_timer_rebalance(struct task_struct *p,
                 left = cputime_div(cputime_sub(expires.cpu, val.cpu),
                                    nthreads);
                 do {
-                        if (!unlikely(t->exit_state)) {
+                        if (!unlikely(t->flags & PF_EXITING)) {
                                 ticks = cputime_add(virt_ticks(t), left);
                                 if (cputime_eq(t->it_virt_expires,
                                                cputime_zero) ||
@@ -527,7 +527,7 @@ static void process_timer_rebalance(struct task_struct *p,
                 nsleft = expires.sched - val.sched;
                 do_div(nsleft, nthreads);
                 do {
-                        if (!unlikely(t->exit_state)) {
+                        if (!unlikely(t->flags & PF_EXITING)) {
                                 ns = t->sched_time + nsleft;
                                 if (t->it_sched_expires == 0 ||
                                     t->it_sched_expires > ns) {
@@ -566,6 +566,9 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
         struct cpu_timer_list *next;
         unsigned long i;
 
+        if (CPUCLOCK_PERTHREAD(timer->it_clock) && (p->flags & PF_EXITING))
+                return;
+
         head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
                 p->cpu_timers : p->signal->cpu_timers);
         head += CPUCLOCK_WHICH(timer->it_clock);
@@ -576,17 +579,15 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
         listpos = head;
         if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
                 list_for_each_entry(next, head, entry) {
-                        if (next->expires.sched > nt->expires.sched) {
-                                listpos = &next->entry;
+                        if (next->expires.sched > nt->expires.sched)
                                 break;
-                        }
+                        listpos = &next->entry;
                 }
         } else {
                 list_for_each_entry(next, head, entry) {
-                        if (cputime_gt(next->expires.cpu, nt->expires.cpu)) {
-                                listpos = &next->entry;
+                        if (cputime_gt(next->expires.cpu, nt->expires.cpu))
                                 break;
-                        }
+                        listpos = &next->entry;
                 }
         }
         list_add(&nt->entry, listpos);
@@ -730,9 +731,15 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags,
          * Disarm any old timer after extracting its expiry time.
          */
         BUG_ON(!irqs_disabled());
+
+        ret = 0;
         spin_lock(&p->sighand->siglock);
         old_expires = timer->it.cpu.expires;
-        list_del_init(&timer->it.cpu.entry);
+        if (unlikely(timer->it.cpu.firing)) {
+                timer->it.cpu.firing = -1;
+                ret = TIMER_RETRY;
+        } else
+                list_del_init(&timer->it.cpu.entry);
         spin_unlock(&p->sighand->siglock);
 
         /*
@@ -780,7 +787,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags,
                 }
         }
 
-        if (unlikely(timer->it.cpu.firing)) {
+        if (unlikely(ret)) {
                 /*
                  * We are colliding with the timer actually firing.
                  * Punt after filling in the timer's old value, and
@@ -788,8 +795,6 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags,
                  * it as an overrun (thanks to bump_cpu_timer above).
                  */
                 read_unlock(&tasklist_lock);
-                timer->it.cpu.firing = -1;
-                ret = TIMER_RETRY;
                 goto out;
         }
 
@@ -955,14 +960,16 @@ void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 static void check_thread_timers(struct task_struct *tsk,
                                 struct list_head *firing)
 {
+        int maxfire;
         struct list_head *timers = tsk->cpu_timers;
 
+        maxfire = 20;
         tsk->it_prof_expires = cputime_zero;
         while (!list_empty(timers)) {
                 struct cpu_timer_list *t = list_entry(timers->next,
                                                       struct cpu_timer_list,
                                                       entry);
-                if (cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
+                if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
                         tsk->it_prof_expires = t->expires.cpu;
                         break;
                 }
@@ -971,12 +978,13 @@ static void check_thread_timers(struct task_struct *tsk,
         }
 
         ++timers;
+        maxfire = 20;
         tsk->it_virt_expires = cputime_zero;
         while (!list_empty(timers)) {
                 struct cpu_timer_list *t = list_entry(timers->next,
                                                       struct cpu_timer_list,
                                                       entry);
-                if (cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
+                if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
                         tsk->it_virt_expires = t->expires.cpu;
                         break;
                 }
@@ -985,12 +993,13 @@ static void check_thread_timers(struct task_struct *tsk,
         }
 
         ++timers;
+        maxfire = 20;
         tsk->it_sched_expires = 0;
         while (!list_empty(timers)) {
                 struct cpu_timer_list *t = list_entry(timers->next,
                                                       struct cpu_timer_list,
                                                       entry);
-                if (tsk->sched_time < t->expires.sched) {
+                if (!--maxfire || tsk->sched_time < t->expires.sched) {
                         tsk->it_sched_expires = t->expires.sched;
                         break;
                 }
@@ -1007,6 +1016,7 @@ static void check_thread_timers(struct task_struct *tsk,
 static void check_process_timers(struct task_struct *tsk,
                                  struct list_head *firing)
 {
+        int maxfire;
         struct signal_struct *const sig = tsk->signal;
         cputime_t utime, stime, ptime, virt_expires, prof_expires;
         unsigned long long sched_time, sched_expires;
@@ -1039,12 +1049,13 @@ static void check_process_timers(struct task_struct *tsk,
         } while (t != tsk);
         ptime = cputime_add(utime, stime);
 
+        maxfire = 20;
         prof_expires = cputime_zero;
         while (!list_empty(timers)) {
                 struct cpu_timer_list *t = list_entry(timers->next,
                                                       struct cpu_timer_list,
                                                       entry);
-                if (cputime_lt(ptime, t->expires.cpu)) {
+                if (!--maxfire || cputime_lt(ptime, t->expires.cpu)) {
                         prof_expires = t->expires.cpu;
                         break;
                 }
@@ -1053,12 +1064,13 @@ static void check_process_timers(struct task_struct *tsk,
         }
 
         ++timers;
+        maxfire = 20;
         virt_expires = cputime_zero;
         while (!list_empty(timers)) {
                 struct cpu_timer_list *t = list_entry(timers->next,
                                                       struct cpu_timer_list,
                                                       entry);
-                if (cputime_lt(utime, t->expires.cpu)) {
+                if (!--maxfire || cputime_lt(utime, t->expires.cpu)) {
                         virt_expires = t->expires.cpu;
                         break;
                 }
@@ -1067,12 +1079,13 @@ static void check_process_timers(struct task_struct *tsk,
         }
 
         ++timers;
+        maxfire = 20;
         sched_expires = 0;
         while (!list_empty(timers)) {
                 struct cpu_timer_list *t = list_entry(timers->next,
                                                       struct cpu_timer_list,
                                                       entry);
-                if (sched_time < t->expires.sched) {
+                if (!--maxfire || sched_time < t->expires.sched) {
                         sched_expires = t->expires.sched;
                         break;
                 }
@@ -1155,6 +1168,9 @@ static void check_process_timers(struct task_struct *tsk,
                 unsigned long long sched_left, sched;
                 const unsigned int nthreads = atomic_read(&sig->live);
 
+                if (!nthreads)
+                        return;
+
                 prof_left = cputime_sub(prof_expires, utime);
                 prof_left = cputime_sub(prof_left, stime);
                 prof_left = cputime_div(prof_left, nthreads);
@@ -1191,7 +1207,7 @@ static void check_process_timers(struct task_struct *tsk,
 
                         do {
                                 t = next_thread(t);
-                        } while (unlikely(t->exit_state));
+                        } while (unlikely(t->flags & PF_EXITING));
                 } while (t != tsk);
         }
 }