X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=kernel%2Fposix-cpu-timers.c;h=9829646d399c5bf0304aa863f78f6f43ae1e4d5e;hp=7d9d0fab1651310f8a4294a418a1d2df4551b7ba;hb=254c8c2dbf0e06a560a5814eb90cb628adb2de66;hpb=1f169f84d25a74fb2dc67274d31d082ce30c60fb

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 7d9d0fa..9829646 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -363,7 +363,7 @@ int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
 				}
 			} else {
 				read_lock(&tasklist_lock);
-				if (thread_group_leader(p) && p->signal) {
+				if (thread_group_leader(p) && p->sighand) {
 					error =
 					    cpu_clock_sample_group(which_clock,
 							           p, &rtn);
@@ -439,7 +439,7 @@ int posix_cpu_timer_del(struct k_itimer *timer)
 
 	if (likely(p != NULL)) {
 		read_lock(&tasklist_lock);
-		if (unlikely(p->signal == NULL)) {
+		if (unlikely(p->sighand == NULL)) {
 			/*
 			 * We raced with the reaping of the task.
 			 * The deletion should have cleared us off the list.
@@ -550,7 +550,7 @@ static inline int expires_gt(cputime_t expires, cputime_t new_exp)
 /*
  * Insert the timer on the appropriate list before any timers that
  * expire later.  This must be called with the tasklist_lock held
- * for reading, and interrupts disabled.
+ * for reading, interrupts disabled and p->sighand->siglock taken.
  */
 static void arm_timer(struct k_itimer *timer)
 {
@@ -569,9 +569,6 @@ static void arm_timer(struct k_itimer *timer)
 	}
 	head += CPUCLOCK_WHICH(timer->it_clock);
 
-	BUG_ON(!irqs_disabled());
-	spin_lock(&p->sighand->siglock);
-
 	listpos = head;
 	list_for_each_entry(next, head, entry) {
 		if (cpu_time_before(timer->it_clock, nt->expires, next->expires))
@@ -606,8 +603,6 @@ static void arm_timer(struct k_itimer *timer)
 			break;
 		}
 	}
-
-	spin_unlock(&p->sighand->siglock);
 }
 
 /*
@@ -696,10 +691,10 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags,
 	read_lock(&tasklist_lock);
 	/*
 	 * We need the tasklist_lock to protect against reaping that
-	 * clears p->signal.  If p has just been reaped, we can no
+	 * clears p->sighand.  If p has just been reaped, we can no
 	 * longer get any information about it at all.
 	 */
-	if (unlikely(p->signal == NULL)) {
+	if (unlikely(p->sighand == NULL)) {
 		read_unlock(&tasklist_lock);
 		put_task_struct(p);
 		timer->it.cpu.task = NULL;
@@ -720,7 +715,6 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags,
 		ret = TIMER_RETRY;
 	} else
 		list_del_init(&timer->it.cpu.entry);
-	spin_unlock(&p->sighand->siglock);
 
 	/*
 	 * We need to sample the current value to convert the new
@@ -774,6 +768,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags,
 		 * disable this firing since we are already reporting
 		 * it as an overrun (thanks to bump_cpu_timer above).
 		 */
+		spin_unlock(&p->sighand->siglock);
 		read_unlock(&tasklist_lock);
 		goto out;
 	}
@@ -793,6 +788,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags,
 		arm_timer(timer);
 	}
 
+	spin_unlock(&p->sighand->siglock);
 	read_unlock(&tasklist_lock);
 
 	/*
@@ -867,7 +863,7 @@ void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 		clear_dead = p->exit_state;
 	} else {
 		read_lock(&tasklist_lock);
-		if (unlikely(p->signal == NULL)) {
+		if (unlikely(p->sighand == NULL)) {
 			/*
 			 * The process has been reaped.
 			 * We can't even collect a sample any more.
@@ -1001,14 +997,11 @@ static void check_thread_timers(struct task_struct *tsk,
 	}
 }
 
-static void stop_process_timers(struct task_struct *tsk)
+static void stop_process_timers(struct signal_struct *sig)
 {
-	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+	struct thread_group_cputimer *cputimer = &sig->cputimer;
 	unsigned long flags;
 
-	if (!cputimer->running)
-		return;
-
 	spin_lock_irqsave(&cputimer->lock, flags);
 	cputimer->running = 0;
 	spin_unlock_irqrestore(&cputimer->lock, flags);
@@ -1048,6 +1041,23 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
 	}
 }
 
+/**
+ * task_cputime_zero - Check a task_cputime struct for all zero fields.
+ *
+ * @cputime:	The struct to compare.
+ *
+ * Checks @cputime to see if all fields are zero.  Returns true if all fields
+ * are zero, false if any field is nonzero.
+ */
+static inline int task_cputime_zero(const struct task_cputime *cputime)
+{
+	if (cputime_eq(cputime->utime, cputime_zero) &&
+	    cputime_eq(cputime->stime, cputime_zero) &&
+	    cputime->sum_exec_runtime == 0)
+		return 1;
+	return 0;
+}
+
 /*
  * Check for any per-thread CPU timers that have fired and move them
  * off the tsk->*_timers list onto the firing list.  Per-thread timers
@@ -1065,19 +1075,6 @@ static void check_process_timers(struct task_struct *tsk,
 	unsigned long soft;
 
 	/*
-	 * Don't sample the current process CPU clocks if there are no timers.
-	 */
-	if (list_empty(&timers[CPUCLOCK_PROF]) &&
-	    cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) &&
-	    sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
-	    list_empty(&timers[CPUCLOCK_VIRT]) &&
-	    cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) &&
-	    list_empty(&timers[CPUCLOCK_SCHED])) {
-		stop_process_timers(tsk);
-		return;
-	}
-
-	/*
 	 * Collect the current process totals.
 	 */
 	thread_group_cputimer(tsk, &cputime);
@@ -1166,18 +1163,11 @@ static void check_process_timers(struct task_struct *tsk,
 		}
 	}
 
-	if (!cputime_eq(prof_expires, cputime_zero) &&
-	    (cputime_eq(sig->cputime_expires.prof_exp, cputime_zero) ||
-	     cputime_gt(sig->cputime_expires.prof_exp, prof_expires)))
-		sig->cputime_expires.prof_exp = prof_expires;
-	if (!cputime_eq(virt_expires, cputime_zero) &&
-	    (cputime_eq(sig->cputime_expires.virt_exp, cputime_zero) ||
-	     cputime_gt(sig->cputime_expires.virt_exp, virt_expires)))
-		sig->cputime_expires.virt_exp = virt_expires;
-	if (sched_expires != 0 &&
-	    (sig->cputime_expires.sched_exp == 0 ||
-	     sig->cputime_expires.sched_exp > sched_expires))
-		sig->cputime_expires.sched_exp = sched_expires;
+	sig->cputime_expires.prof_exp = prof_expires;
+	sig->cputime_expires.virt_exp = virt_expires;
+	sig->cputime_expires.sched_exp = sched_expires;
+	if (task_cputime_zero(&sig->cputime_expires))
+		stop_process_timers(sig);
 }
 
 /*
@@ -1206,9 +1196,10 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
 			goto out;
 		}
 		read_lock(&tasklist_lock); /* arm_timer needs it.  */
+		spin_lock(&p->sighand->siglock);
 	} else {
 		read_lock(&tasklist_lock);
-		if (unlikely(p->signal == NULL)) {
+		if (unlikely(p->sighand == NULL)) {
 			/*
 			 * The process has been reaped.
 			 * We can't even collect a sample any more.
@@ -1226,6 +1217,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
 			clear_dead_task(timer, now);
 			goto out_unlock;
 		}
+		spin_lock(&p->sighand->siglock);
 		cpu_timer_sample_group(timer->it_clock, p, &now);
 		bump_cpu_timer(timer, now);
 		/* Leave the tasklist_lock locked for the call below.  */
@@ -1234,7 +1226,9 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
 	/*
 	 * Now re-arm for the new expiry time.
 	 */
+	BUG_ON(!irqs_disabled());
 	arm_timer(timer);
+	spin_unlock(&p->sighand->siglock);
 
 out_unlock:
 	read_unlock(&tasklist_lock);
@@ -1246,23 +1240,6 @@ out:
 }
 
 /**
- * task_cputime_zero - Check a task_cputime struct for all zero fields.
- *
- * @cputime:	The struct to compare.
- *
- * Checks @cputime to see if all fields are zero.  Returns true if all fields
- * are zero, false if any field is nonzero.
- */
-static inline int task_cputime_zero(const struct task_cputime *cputime)
-{
-	if (cputime_eq(cputime->utime, cputime_zero) &&
-	    cputime_eq(cputime->stime, cputime_zero) &&
-	    cputime->sum_exec_runtime == 0)
-		return 1;
-	return 0;
-}
-
-/**
  * task_cputime_expired - Compare two task_cputime entities.
  *
  * @sample:	The task_cputime structure to be checked for expiration.
@@ -1318,7 +1295,7 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
 	}
 
 	sig = tsk->signal;
-	if (!task_cputime_zero(&sig->cputime_expires)) {
+	if (sig->cputimer.running) {
 		struct task_cputime group_sample;
 
 		thread_group_cputimer(tsk, &group_sample);
@@ -1355,7 +1332,12 @@ void run_posix_cpu_timers(struct task_struct *tsk)
 	 * put them on the firing list.
 	 */
 	check_thread_timers(tsk, &firing);
-	check_process_timers(tsk, &firing);
+	/*
+	 * If there are any active process wide timers (POSIX 1.b, itimers,
+	 * RLIMIT_CPU) cputimer must be running.
+	 */
+	if (tsk->signal->cputimer.running)
+		check_process_timers(tsk, &firing);
 
 	/*
 	 * We must release these locks before taking any timer's lock.