X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fposix-cpu-timers.c;h=68c96376e84a6078da9c07d6ebfc2b1c64a3e2a7;hb=a3aaabd6b402d8b0ede5aa4a040e9fdbbfdf9116;hp=520f6c59948d24c55721c2a2299defe964efaadf;hpb=944d79559d154c12becde0dab327016cf438f46c;p=linux-2.6

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 520f6c5994..68c96376e8 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -21,8 +21,8 @@ static int check_clock(const clockid_t which_clock)
 
 	read_lock(&tasklist_lock);
 	p = find_task_by_pid(pid);
-	if (!p || (CPUCLOCK_PERTHREAD(which_clock) ?
-		   p->tgid != current->tgid : p->tgid != pid)) {
+	if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
+		   same_thread_group(p, current) : thread_group_leader(p))) {
 		error = -EINVAL;
 	}
 	read_unlock(&tasklist_lock);
@@ -87,6 +87,19 @@ static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
 	return a;
 }
 
+/*
+ * Divide and limit the result to res >= 1
+ *
+ * This is necessary to prevent signal delivery starvation, when the result of
+ * the division would be rounded down to 0.
+ */
+static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
+{
+	cputime_t res = cputime_div(time, div);
+
+	return max_t(cputime_t, res, 1);
+}
+
 /*
  * Update expiry time from increment, and increase overrun count,
  * given the current clock sample.
@@ -148,7 +161,7 @@ static inline cputime_t virt_ticks(struct task_struct *p)
 }
 static inline unsigned long long sched_ns(struct task_struct *p)
 {
-	return (p == current) ? current_sched_time(p) : p->sched_time;
+	return task_sched_runtime(p);
 }
 
 int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
@@ -233,10 +246,10 @@ static int cpu_clock_sample_group_locked(unsigned int clock_idx,
 		} while (t != p);
 		break;
 	case CPUCLOCK_SCHED:
-		cpu->sched = p->signal->sched_time;
+		cpu->sched = p->signal->sum_sched_runtime;
 		/* Add in each other live thread.  */
 		while ((t = next_thread(t)) != p) {
-			cpu->sched += t->sched_time;
+			cpu->sched += t->se.sum_exec_runtime;
 		}
 		cpu->sched += sched_ns(p);
 		break;
@@ -291,20 +304,25 @@ int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
 		 * should be able to see it.
 		 */
 		struct task_struct *p;
-		read_lock(&tasklist_lock);
+		rcu_read_lock();
 		p = find_task_by_pid(pid);
 		if (p) {
 			if (CPUCLOCK_PERTHREAD(which_clock)) {
-				if (p->tgid == current->tgid) {
+				if (same_thread_group(p, current)) {
 					error = cpu_clock_sample(which_clock,
 								 p, &rtn);
 				}
-			} else if (p->tgid == pid && p->signal) {
-				error = cpu_clock_sample_group(which_clock,
-							       p, &rtn);
+			} else {
+				read_lock(&tasklist_lock);
+				if (thread_group_leader(p) && p->signal) {
+					error =
+					    cpu_clock_sample_group(which_clock,
+							           p, &rtn);
+				}
+				read_unlock(&tasklist_lock);
 			}
 		}
-		read_unlock(&tasklist_lock);
+		rcu_read_unlock();
 	}
 
 	if (error)
@@ -337,7 +355,7 @@ int posix_cpu_timer_create(struct k_itimer *new_timer)
 			p = current;
 		} else {
 			p = find_task_by_pid(pid);
-			if (p && p->tgid != current->tgid)
+			if (p && !same_thread_group(p, current))
 				p = NULL;
 		}
 	} else {
@@ -345,7 +363,7 @@ int posix_cpu_timer_create(struct k_itimer *new_timer)
 			p = current->group_leader;
 		} else {
 			p = find_task_by_pid(pid);
-			if (p && p->tgid != pid)
+			if (p && !thread_group_leader(p))
 				p = NULL;
 		}
 	}
@@ -404,7 +422,7 @@ int posix_cpu_timer_del(struct k_itimer *timer)
  */
 static void cleanup_timers(struct list_head *head,
 			   cputime_t utime, cputime_t stime,
-			   unsigned long long sched_time)
+			   unsigned long long sum_exec_runtime)
 {
 	struct cpu_timer_list *timer, *next;
 	cputime_t ptime = cputime_add(utime, stime);
@@ -433,10 +451,10 @@ static void cleanup_timers(struct list_head *head,
 	++head;
 	list_for_each_entry_safe(timer, next, head, entry) {
 		list_del_init(&timer->entry);
-		if (timer->expires.sched < sched_time) {
+		if (timer->expires.sched < sum_exec_runtime) {
 			timer->expires.sched = 0;
 		} else {
-			timer->expires.sched -= sched_time;
+			timer->expires.sched -= sum_exec_runtime;
 		}
 	}
 }
@@ -449,7 +467,7 @@ static void cleanup_timers(struct list_head *head,
 void posix_cpu_timers_exit(struct task_struct *tsk)
 {
 	cleanup_timers(tsk->cpu_timers,
-		       tsk->utime, tsk->stime, tsk->sched_time);
+		       tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
 
 }
 void posix_cpu_timers_exit_group(struct task_struct *tsk)
@@ -457,7 +475,7 @@ void posix_cpu_timers_exit_group(struct task_struct *tsk)
 	cleanup_timers(tsk->signal->cpu_timers,
 		       cputime_add(tsk->utime, tsk->signal->utime),
 		       cputime_add(tsk->stime, tsk->signal->stime),
-		       tsk->sched_time + tsk->signal->sched_time);
+		     tsk->se.sum_exec_runtime + tsk->signal->sum_sched_runtime);
 }
 
 
@@ -483,8 +501,8 @@ static void process_timer_rebalance(struct task_struct *p,
 		BUG();
 		break;
 	case CPUCLOCK_PROF:
-		left = cputime_div(cputime_sub(expires.cpu, val.cpu),
-				   nthreads);
+		left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
+				       nthreads);
 		do {
 			if (likely(!(t->flags & PF_EXITING))) {
 				ticks = cputime_add(prof_ticks(t), left);
@@ -498,8 +516,8 @@ static void process_timer_rebalance(struct task_struct *p,
 		} while (t != p);
 		break;
 	case CPUCLOCK_VIRT:
-		left = cputime_div(cputime_sub(expires.cpu, val.cpu),
-				   nthreads);
+		left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
+				       nthreads);
 		do {
 			if (likely(!(t->flags & PF_EXITING))) {
 				ticks = cputime_add(virt_ticks(t), left);
@@ -515,9 +533,10 @@ static void process_timer_rebalance(struct task_struct *p,
 	case CPUCLOCK_SCHED:
 		nsleft = expires.sched - val.sched;
 		do_div(nsleft, nthreads);
+		nsleft = max_t(unsigned long long, nsleft, 1);
 		do {
 			if (likely(!(t->flags & PF_EXITING))) {
-				ns = t->sched_time + nsleft;
+				ns = t->se.sum_exec_runtime + nsleft;
 				if (t->it_sched_expires == 0 ||
 				    t->it_sched_expires > ns) {
 					t->it_sched_expires = ns;
@@ -555,9 +574,6 @@ 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);
@@ -955,7 +971,7 @@ static void check_thread_timers(struct task_struct *tsk,
 	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 *t = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
 		if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
@@ -970,7 +986,7 @@ static void check_thread_timers(struct task_struct *tsk,
 	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 *t = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
 		if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
@@ -985,10 +1001,10 @@ static void check_thread_timers(struct task_struct *tsk,
 	maxfire = 20;
 	tsk->it_sched_expires = 0;
 	while (!list_empty(timers)) {
-		struct cpu_timer_list *t = list_entry(timers->next,
+		struct cpu_timer_list *t = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
-		if (!--maxfire || tsk->sched_time < t->expires.sched) {
+		if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
 			tsk->it_sched_expires = t->expires.sched;
 			break;
 		}
@@ -1008,7 +1024,7 @@ static void check_process_timers(struct task_struct *tsk,
 	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;
+	unsigned long long sum_sched_runtime, sched_expires;
 	struct task_struct *t;
 	struct list_head *timers = sig->cpu_timers;
 
@@ -1028,12 +1044,12 @@ static void check_process_timers(struct task_struct *tsk,
 	 */
 	utime = sig->utime;
 	stime = sig->stime;
-	sched_time = sig->sched_time;
+	sum_sched_runtime = sig->sum_sched_runtime;
 	t = tsk;
 	do {
 		utime = cputime_add(utime, t->utime);
 		stime = cputime_add(stime, t->stime);
-		sched_time += t->sched_time;
+		sum_sched_runtime += t->se.sum_exec_runtime;
 		t = next_thread(t);
 	} while (t != tsk);
 	ptime = cputime_add(utime, stime);
@@ -1041,7 +1057,7 @@ static void check_process_timers(struct task_struct *tsk,
 	maxfire = 20;
 	prof_expires = cputime_zero;
 	while (!list_empty(timers)) {
-		struct cpu_timer_list *t = list_entry(timers->next,
+		struct cpu_timer_list *t = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
 		if (!--maxfire || cputime_lt(ptime, t->expires.cpu)) {
@@ -1056,7 +1072,7 @@ static void check_process_timers(struct task_struct *tsk,
 	maxfire = 20;
 	virt_expires = cputime_zero;
 	while (!list_empty(timers)) {
-		struct cpu_timer_list *t = list_entry(timers->next,
+		struct cpu_timer_list *t = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
 		if (!--maxfire || cputime_lt(utime, t->expires.cpu)) {
@@ -1071,10 +1087,10 @@ static void check_process_timers(struct task_struct *tsk,
 	maxfire = 20;
 	sched_expires = 0;
 	while (!list_empty(timers)) {
-		struct cpu_timer_list *t = list_entry(timers->next,
+		struct cpu_timer_list *t = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
-		if (!--maxfire || sched_time < t->expires.sched) {
+		if (!--maxfire || sum_sched_runtime < t->expires.sched) {
 			sched_expires = t->expires.sched;
 			break;
 		}
@@ -1162,17 +1178,21 @@ static void check_process_timers(struct task_struct *tsk,
 
 		prof_left = cputime_sub(prof_expires, utime);
 		prof_left = cputime_sub(prof_left, stime);
-		prof_left = cputime_div(prof_left, nthreads);
+		prof_left = cputime_div_non_zero(prof_left, nthreads);
 		virt_left = cputime_sub(virt_expires, utime);
-		virt_left = cputime_div(virt_left, nthreads);
+		virt_left = cputime_div_non_zero(virt_left, nthreads);
 		if (sched_expires) {
-			sched_left = sched_expires - sched_time;
+			sched_left = sched_expires - sum_sched_runtime;
 			do_div(sched_left, nthreads);
+			sched_left = max_t(unsigned long long, sched_left, 1);
 		} else {
 			sched_left = 0;
 		}
 		t = tsk;
 		do {
+			if (unlikely(t->flags & PF_EXITING))
+				continue;
+
 			ticks = cputime_add(cputime_add(t->utime, t->stime),
 					    prof_left);
 			if (!cputime_eq(prof_expires, cputime_zero) &&
@@ -1188,16 +1208,12 @@ static void check_process_timers(struct task_struct *tsk,
 				t->it_virt_expires = ticks;
 			}
 
-			sched = t->sched_time + sched_left;
+			sched = t->se.sum_exec_runtime + sched_left;
 			if (sched_expires && (t->it_sched_expires == 0 ||
 					      t->it_sched_expires > sched)) {
 				t->it_sched_expires = sched;
 			}
-
-			do {
-				t = next_thread(t);
-			} while (unlikely(t->flags & PF_EXITING));
-		} while (t != tsk);
+		} while ((t = next_thread(t)) != tsk);
 	}
 }
 
@@ -1284,35 +1300,35 @@ void run_posix_cpu_timers(struct task_struct *tsk)
 
 	if (UNEXPIRED(prof) && UNEXPIRED(virt) &&
 	    (tsk->it_sched_expires == 0 ||
-	     tsk->sched_time < tsk->it_sched_expires))
+	     tsk->se.sum_exec_runtime < tsk->it_sched_expires))
 		return;
 
 #undef	UNEXPIRED
 
-	BUG_ON(tsk->exit_state);
-
 	/*
 	 * Double-check with locks held.
 	 */
 	read_lock(&tasklist_lock);
-	spin_lock(&tsk->sighand->siglock);
+	if (likely(tsk->signal != NULL)) {
+		spin_lock(&tsk->sighand->siglock);
 
-	/*
-	 * Here we take off tsk->cpu_timers[N] and tsk->signal->cpu_timers[N]
-	 * all the timers that are firing, and put them on the firing list.
-	 */
-	check_thread_timers(tsk, &firing);
-	check_process_timers(tsk, &firing);
+		/*
+		 * Here we take off tsk->cpu_timers[N] and tsk->signal->cpu_timers[N]
+		 * all the timers that are firing, and put them on the firing list.
+		 */
+		check_thread_timers(tsk, &firing);
+		check_process_timers(tsk, &firing);
 
-	/*
-	 * We must release these locks before taking any timer's lock.
-	 * There is a potential race with timer deletion here, as the
-	 * siglock now protects our private firing list.  We have set
-	 * the firing flag in each timer, so that a deletion attempt
-	 * 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);
+		/*
+		 * We must release these locks before taking any timer's lock.
+		 * There is a potential race with timer deletion here, as the
+		 * siglock now protects our private firing list.  We have set
+		 * the firing flag in each timer, so that a deletion attempt
+		 * 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);
+	}
 	read_unlock(&tasklist_lock);
 
 	/*
@@ -1384,7 +1400,7 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
 	 */
 	head = &tsk->signal->cpu_timers[clock_idx];
 	if (list_empty(head) ||
-	    cputime_ge(list_entry(head->next,
+	    cputime_ge(list_first_entry(head,
 				  struct cpu_timer_list, entry)->expires.cpu,
 		       *newval)) {
 		/*
@@ -1397,24 +1413,12 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
 	}
 }
 
-static long posix_cpu_clock_nanosleep_restart(struct restart_block *);
-
-int posix_cpu_nsleep(const clockid_t which_clock, int flags,
-		     struct timespec *rqtp, struct timespec __user *rmtp)
+static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
+			    struct timespec *rqtp, struct itimerspec *it)
 {
-	struct restart_block *restart_block =
-	    &current_thread_info()->restart_block;
 	struct k_itimer timer;
 	int error;
 
-	/*
-	 * Diagnose required errors first.
-	 */
-	if (CPUCLOCK_PERTHREAD(which_clock) &&
-	    (CPUCLOCK_PID(which_clock) == 0 ||
-	     CPUCLOCK_PID(which_clock) == current->pid))
-		return -EINVAL;
-
 	/*
 	 * Set up a temporary timer and then wait for it to go off.
 	 */
@@ -1426,11 +1430,12 @@ int posix_cpu_nsleep(const clockid_t which_clock, int flags,
 	timer.it_process = current;
 	if (!error) {
 		static struct itimerspec zero_it;
-		struct itimerspec it = { .it_value = *rqtp,
-					 .it_interval = {} };
+
+		memset(it, 0, sizeof *it);
+		it->it_value = *rqtp;
 
 		spin_lock_irq(&timer.it_lock);
-		error = posix_cpu_timer_set(&timer, flags, &it, NULL);
+		error = posix_cpu_timer_set(&timer, flags, it, NULL);
 		if (error) {
 			spin_unlock_irq(&timer.it_lock);
 			return error;
@@ -1458,49 +1463,89 @@ int posix_cpu_nsleep(const clockid_t which_clock, int flags,
 		 * We were interrupted by a signal.
 		 */
 		sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
-		posix_cpu_timer_set(&timer, 0, &zero_it, &it);
+		posix_cpu_timer_set(&timer, 0, &zero_it, it);
 		spin_unlock_irq(&timer.it_lock);
 
-		if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
+		if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
 			/*
 			 * It actually did fire already.
 			 */
 			return 0;
 		}
 
+		error = -ERESTART_RESTARTBLOCK;
+	}
+
+	return error;
+}
+
+int posix_cpu_nsleep(const clockid_t which_clock, int flags,
+		     struct timespec *rqtp, struct timespec __user *rmtp)
+{
+	struct restart_block *restart_block =
+	    &current_thread_info()->restart_block;
+	struct itimerspec it;
+	int error;
+
+	/*
+	 * Diagnose required errors first.
+	 */
+	if (CPUCLOCK_PERTHREAD(which_clock) &&
+	    (CPUCLOCK_PID(which_clock) == 0 ||
+	     CPUCLOCK_PID(which_clock) == current->pid))
+		return -EINVAL;
+
+	error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
+
+	if (error == -ERESTART_RESTARTBLOCK) {
+
+	       	if (flags & TIMER_ABSTIME)
+			return -ERESTARTNOHAND;
 		/*
-		 * Report back to the user the time still remaining.
-		 */
-		if (rmtp != NULL && !(flags & TIMER_ABSTIME) &&
-		    copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
+	 	 * Report back to the user the time still remaining.
+	 	 */
+		if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
 			return -EFAULT;
 
-		restart_block->fn = posix_cpu_clock_nanosleep_restart;
-		/* Caller already set restart_block->arg1 */
+		restart_block->fn = posix_cpu_nsleep_restart;
 		restart_block->arg0 = which_clock;
 		restart_block->arg1 = (unsigned long) rmtp;
 		restart_block->arg2 = rqtp->tv_sec;
 		restart_block->arg3 = rqtp->tv_nsec;
-
-		error = -ERESTART_RESTARTBLOCK;
 	}
-
 	return error;
 }
 
-static long
-posix_cpu_clock_nanosleep_restart(struct restart_block *restart_block)
+long posix_cpu_nsleep_restart(struct restart_block *restart_block)
 {
 	clockid_t which_clock = restart_block->arg0;
 	struct timespec __user *rmtp;
 	struct timespec t;
+	struct itimerspec it;
+	int error;
 
 	rmtp = (struct timespec __user *) restart_block->arg1;
 	t.tv_sec = restart_block->arg2;
 	t.tv_nsec = restart_block->arg3;
 
 	restart_block->fn = do_no_restart_syscall;
-	return posix_cpu_nsleep(which_clock, TIMER_ABSTIME, &t, rmtp);
+	error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
+
+	if (error == -ERESTART_RESTARTBLOCK) {
+		/*
+	 	 * Report back to the user the time still remaining.
+	 	 */
+		if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
+			return -EFAULT;
+
+		restart_block->fn = posix_cpu_nsleep_restart;
+		restart_block->arg0 = which_clock;
+		restart_block->arg1 = (unsigned long) rmtp;
+		restart_block->arg2 = t.tv_sec;
+		restart_block->arg3 = t.tv_nsec;
+	}
+	return error;
+
 }
 
 
@@ -1528,6 +1573,10 @@ static int process_cpu_nsleep(const clockid_t which_clock, int flags,
 {
 	return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
 }
+static long process_cpu_nsleep_restart(struct restart_block *restart_block)
+{
+	return -EINVAL;
+}
 static int thread_cpu_clock_getres(const clockid_t which_clock,
 				   struct timespec *tp)
 {
@@ -1548,6 +1597,10 @@ static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
 {
 	return -EINVAL;
 }
+static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
+{
+	return -EINVAL;
+}
 
 static __init int init_posix_cpu_timers(void)
 {
@@ -1557,6 +1610,7 @@ static __init int init_posix_cpu_timers(void)
 		.clock_set = do_posix_clock_nosettime,
 		.timer_create = process_cpu_timer_create,
 		.nsleep = process_cpu_nsleep,
+		.nsleep_restart = process_cpu_nsleep_restart,
 	};
 	struct k_clock thread = {
 		.clock_getres = thread_cpu_clock_getres,
@@ -1564,6 +1618,7 @@ static __init int init_posix_cpu_timers(void)
 		.clock_set = do_posix_clock_nosettime,
 		.timer_create = thread_cpu_timer_create,
 		.nsleep = thread_cpu_nsleep,
+		.nsleep_restart = thread_cpu_nsleep_restart,
 	};
 
 	register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);