Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rcu: fix rcutorture bug
  rcu: eliminate synchronize_rcu_xxx macro
  rcu: make treercu safe for suspend and resume
  rcu: fix rcutree grace-period-latency bug on small systems
  futex: catch certain assymetric (get|put)_futex_key calls
  futex: make futex_(get|put)_key() calls symmetric
  locking, percpu counters: introduce separate lock classes
  swiotlb: clean up EXPORT_SYMBOL usage
  swiotlb: remove unnecessary declaration
  swiotlb: replace architecture-specific swiotlb.h with linux/swiotlb.h
  swiotlb: add support for systems with highmem
  swiotlb: store phys address in io_tlb_orig_addr array
  swiotlb: add hwdev to swiotlb_phys_to_bus() / swiotlb_sg_to_bus()

kernel/futex.c

@@ -170,8 +170,11 @@ static void get_futex_key_refs(union futex_key *key)
  */
 static void drop_futex_key_refs(union futex_key *key)
 {
-	if (!key->both.ptr)
+	if (!key->both.ptr) {
+		/* If we're here then we tried to put a key we failed to get */
+		WARN_ON_ONCE(1);
 		return;
+	}
 
 	switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
 	case FUT_OFF_INODE:
@@ -730,8 +733,8 @@ static int futex_wake(u32 __user *uaddr, int fshared, int nr_wake, u32 bitset)
 	}
 
 	spin_unlock(&hb->lock);
-out:
 	put_futex_key(fshared, &key);
+out:
 	return ret;
 }
 
@@ -755,7 +758,7 @@ retryfull:
 		goto out;
 	ret = get_futex_key(uaddr2, fshared, &key2);
 	if (unlikely(ret != 0))
-		goto out;
+		goto out_put_key1;
 
 	hb1 = hash_futex(&key1);
 	hb2 = hash_futex(&key2);
@@ -777,12 +780,12 @@ retry:
 		 * but we might get them from range checking
 		 */
 		ret = op_ret;
-		goto out;
+		goto out_put_keys;
 #endif
 
 		if (unlikely(op_ret != -EFAULT)) {
 			ret = op_ret;
-			goto out;
+			goto out_put_keys;
 		}
 
 		/*
@@ -796,7 +799,7 @@ retry:
 			ret = futex_handle_fault((unsigned long)uaddr2,
 						 attempt);
 			if (ret)
-				goto out;
+				goto out_put_keys;
 			goto retry;
 		}
 
@@ -834,10 +837,11 @@ retry:
 	spin_unlock(&hb1->lock);
 	if (hb1 != hb2)
 		spin_unlock(&hb2->lock);
-out:
+out_put_keys:
 	put_futex_key(fshared, &key2);
+out_put_key1:
 	put_futex_key(fshared, &key1);
-
+out:
 	return ret;
 }
 
@@ -854,13 +858,13 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
 	struct futex_q *this, *next;
 	int ret, drop_count = 0;
 
- retry:
+retry:
 	ret = get_futex_key(uaddr1, fshared, &key1);
 	if (unlikely(ret != 0))
 		goto out;
 	ret = get_futex_key(uaddr2, fshared, &key2);
 	if (unlikely(ret != 0))
-		goto out;
+		goto out_put_key1;
 
 	hb1 = hash_futex(&key1);
 	hb2 = hash_futex(&key2);
@@ -882,7 +886,7 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
 			if (!ret)
 				goto retry;
 
-			return ret;
+			goto out_put_keys;
 		}
 		if (curval != *cmpval) {
 			ret = -EAGAIN;
@@ -927,9 +931,11 @@ out_unlock:
 	while (--drop_count >= 0)
 		drop_futex_key_refs(&key1);
 
-out:
+out_put_keys:
 	put_futex_key(fshared, &key2);
+out_put_key1:
 	put_futex_key(fshared, &key1);
+out:
 	return ret;
 }
 
@@ -990,7 +996,7 @@ static int unqueue_me(struct futex_q *q)
 	int ret = 0;
 
 	/* In the common case we don't take the spinlock, which is nice. */
- retry:
+retry:
 	lock_ptr = q->lock_ptr;
 	barrier();
 	if (lock_ptr != NULL) {
@@ -1172,11 +1178,11 @@ static int futex_wait(u32 __user *uaddr, int fshared,
 
 	q.pi_state = NULL;
 	q.bitset = bitset;
- retry:
+retry:
 	q.key = FUTEX_KEY_INIT;
 	ret = get_futex_key(uaddr, fshared, &q.key);
 	if (unlikely(ret != 0))
-		goto out_release_sem;
+		goto out;
 
 	hb = queue_lock(&q);
 
@@ -1204,6 +1210,7 @@ static int futex_wait(u32 __user *uaddr, int fshared,
 
 	if (unlikely(ret)) {
 		queue_unlock(&q, hb);
+		put_futex_key(fshared, &q.key);
 
 		ret = get_user(uval, uaddr);
 
@@ -1213,7 +1220,7 @@ static int futex_wait(u32 __user *uaddr, int fshared,
 	}
 	ret = -EWOULDBLOCK;
 	if (uval != val)
-		goto out_unlock_release_sem;
+		goto out_unlock_put_key;
 
 	/* Only actually queue if *uaddr contained val.  */
 	queue_me(&q, hb);
@@ -1305,11 +1312,11 @@ static int futex_wait(u32 __user *uaddr, int fshared,
 		return -ERESTART_RESTARTBLOCK;
 	}
 
- out_unlock_release_sem:
+out_unlock_put_key:
 	queue_unlock(&q, hb);
-
- out_release_sem:
 	put_futex_key(fshared, &q.key);
+
+out:
 	return ret;
 }
 
@@ -1358,16 +1365,16 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
 	}
 
 	q.pi_state = NULL;
- retry:
+retry:
 	q.key = FUTEX_KEY_INIT;
 	ret = get_futex_key(uaddr, fshared, &q.key);
 	if (unlikely(ret != 0))
-		goto out_release_sem;
+		goto out;
 
- retry_unlocked:
+retry_unlocked:
 	hb = queue_lock(&q);
 
- retry_locked:
+retry_locked:
 	ret = lock_taken = 0;
 
 	/*
@@ -1388,14 +1395,14 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
 	 */
 	if (unlikely((curval & FUTEX_TID_MASK) == task_pid_vnr(current))) {
 		ret = -EDEADLK;
-		goto out_unlock_release_sem;
+		goto out_unlock_put_key;
 	}
 
 	/*
 	 * Surprise - we got the lock. Just return to userspace:
 	 */
 	if (unlikely(!curval))
-		goto out_unlock_release_sem;
+		goto out_unlock_put_key;
 
 	uval = curval;
 
@@ -1431,7 +1438,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
 	 * We took the lock due to owner died take over.
 	 */
 	if (unlikely(lock_taken))
-		goto out_unlock_release_sem;
+		goto out_unlock_put_key;
 
 	/*
 	 * We dont have the lock. Look up the PI state (or create it if
@@ -1470,7 +1477,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
 				goto retry_locked;
 			}
 		default:
-			goto out_unlock_release_sem;
+			goto out_unlock_put_key;
 		}
 	}
 
@@ -1561,16 +1568,17 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
 		destroy_hrtimer_on_stack(&to->timer);
 	return ret != -EINTR ? ret : -ERESTARTNOINTR;
 
- out_unlock_release_sem:
+out_unlock_put_key:
 	queue_unlock(&q, hb);
 
- out_release_sem:
+out_put_key:
 	put_futex_key(fshared, &q.key);
+out:
 	if (to)
 		destroy_hrtimer_on_stack(&to->timer);
 	return ret;
 
- uaddr_faulted:
+uaddr_faulted:
 	/*
 	 * We have to r/w  *(int __user *)uaddr, and we have to modify it
 	 * atomically.  Therefore, if we continue to fault after get_user()
@@ -1583,7 +1591,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
 	if (attempt++) {
 		ret = futex_handle_fault((unsigned long)uaddr, attempt);
 		if (ret)
-			goto out_release_sem;
+			goto out_put_key;
 		goto retry_unlocked;
 	}
 
@@ -1675,9 +1683,9 @@ retry_unlocked:
 
 out_unlock:
 	spin_unlock(&hb->lock);
-out:
 	put_futex_key(fshared, &key);
 
+out:
 	return ret;
 
 pi_faulted:

kernel/rcupdate.c

@@ -77,8 +77,15 @@ void wakeme_after_rcu(struct rcu_head  *head)
  * sections are delimited by rcu_read_lock() and rcu_read_unlock(),
  * and may be nested.
  */
-void synchronize_rcu(void);	/* Makes kernel-doc tools happy */
-synchronize_rcu_xxx(synchronize_rcu, call_rcu)
+void synchronize_rcu(void)
+{
+	struct rcu_synchronize rcu;
+	init_completion(&rcu.completion);
+	/* Will wake me after RCU finished. */
+	call_rcu(&rcu.head, wakeme_after_rcu);
+	/* Wait for it. */
+	wait_for_completion(&rcu.completion);
+}
 EXPORT_SYMBOL_GPL(synchronize_rcu);
 
 static void rcu_barrier_callback(struct rcu_head *notused)

kernel/rcupreempt.c

@@ -1177,7 +1177,16 @@ EXPORT_SYMBOL_GPL(call_rcu_sched);
  * in -rt this does -not- necessarily result in all currently executing
  * interrupt -handlers- having completed.
  */
-synchronize_rcu_xxx(__synchronize_sched, call_rcu_sched)
+void __synchronize_sched(void)
+{
+	struct rcu_synchronize rcu;
+
+	init_completion(&rcu.completion);
+	/* Will wake me after RCU finished. */
+	call_rcu_sched(&rcu.head, wakeme_after_rcu);
+	/* Wait for it. */
+	wait_for_completion(&rcu.completion);
+}
 EXPORT_SYMBOL_GPL(__synchronize_sched);
 
 /*

kernel/rcutorture.c

@@ -136,7 +136,7 @@ static int stutter_pause_test = 0;
 #endif
 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
 
-#define FULLSTOP_SIGNALED 1	/* Bail due to signal. */
+#define FULLSTOP_SHUTDOWN 1	/* Bail due to system shutdown/panic. */
 #define FULLSTOP_CLEANUP  2	/* Orderly shutdown. */
 static int fullstop;		/* stop generating callbacks at test end. */
 DEFINE_MUTEX(fullstop_mutex);	/* protect fullstop transitions and */
@@ -151,12 +151,10 @@ rcutorture_shutdown_notify(struct notifier_block *unused1,
 {
 	if (fullstop)
 		return NOTIFY_DONE;
-	if (signal_pending(current)) {
-		mutex_lock(&fullstop_mutex);
-		if (!ACCESS_ONCE(fullstop))
-			fullstop = FULLSTOP_SIGNALED;
-		mutex_unlock(&fullstop_mutex);
-	}
+	mutex_lock(&fullstop_mutex);
+	if (!fullstop)
+		fullstop = FULLSTOP_SHUTDOWN;
+	mutex_unlock(&fullstop_mutex);
 	return NOTIFY_DONE;
 }
 
@@ -624,7 +622,7 @@ rcu_torture_writer(void *arg)
 		rcu_stutter_wait();
 	} while (!kthread_should_stop() && !fullstop);
 	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
-	while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+	while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
 		schedule_timeout_uninterruptible(1);
 	return 0;
 }
@@ -649,7 +647,7 @@ rcu_torture_fakewriter(void *arg)
 	} while (!kthread_should_stop() && !fullstop);
 
 	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
-	while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+	while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
 		schedule_timeout_uninterruptible(1);
 	return 0;
 }
@@ -759,7 +757,7 @@ rcu_torture_reader(void *arg)
 	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
 	if (irqreader && cur_ops->irqcapable)
 		del_timer_sync(&t);
-	while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+	while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
 		schedule_timeout_uninterruptible(1);
 	return 0;
 }

kernel/rcutree.c

@@ -79,7 +79,10 @@ struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
 DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
 
 #ifdef CONFIG_NO_HZ
-DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks);
+DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
+	.dynticks_nesting = 1,
+	.dynticks = 1,
+};
 #endif /* #ifdef CONFIG_NO_HZ */
 
 static int blimit = 10;		/* Maximum callbacks per softirq. */
@@ -572,6 +575,7 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
 	/* Special-case the common single-level case. */
 	if (NUM_RCU_NODES == 1) {
 		rnp->qsmask = rnp->qsmaskinit;
+		rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state OK. */
 		spin_unlock_irqrestore(&rnp->lock, flags);
 		return;
 	}
@@ -1379,13 +1383,6 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
 
 static void __cpuinit rcu_online_cpu(int cpu)
 {
-#ifdef CONFIG_NO_HZ
-	struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
-
-	rdtp->dynticks_nesting = 1;
-	rdtp->dynticks |= 1; 	/* need consecutive #s even for hotplug. */
-	rdtp->dynticks_nmi = (rdtp->dynticks_nmi + 1) & ~0x1;
-#endif /* #ifdef CONFIG_NO_HZ */
 	rcu_init_percpu_data(cpu, &rcu_state);
 	rcu_init_percpu_data(cpu, &rcu_bh_state);
 	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);