Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Conflicts:
	drivers/net/ethernet/cadence/macb.c
	drivers/net/phy/phy.c
	include/linux/skbuff.h
	net/ipv4/tcp.c
	net/switchdev/switchdev.c

Switchdev was a case of RTNH_H_{EXTERNAL --> OFFLOAD}
renaming overlapping with net-next changes of various
sorts.

phy.c was a case of two changes, one adding a local
variable to a function whilst the second was removing
one.

tcp.c overlapped a deadlock fix with the addition of new tcp_info
statistic values.

macb.c involved the addition of two zyncq device entries.

skbuff.h involved adding back ipv4_daddr to nf_bridge_info
whilst net-next changes put two other existing members of
that struct into a union.

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 82 insertions, 50 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 81aa3a4ece9f..1a3bf48743ce 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -913,10 +913,30 @@ static void put_ctx(struct perf_event_context *ctx)
  * Those places that change perf_event::ctx will hold both
  * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
  *
- * Lock ordering is by mutex address. There is one other site where
- * perf_event_context::mutex nests and that is put_event(). But remember that
- * that is a parent<->child context relation, and migration does not affect
- * children, therefore these two orderings should not interact.
+ * Lock ordering is by mutex address. There are two other sites where
+ * perf_event_context::mutex nests and those are:
+ *
+ *  - perf_event_exit_task_context()	[ child , 0 ]
+ *      __perf_event_exit_task()
+ *        sync_child_event()
+ *          put_event()			[ parent, 1 ]
+ *
+ *  - perf_event_init_context()		[ parent, 0 ]
+ *      inherit_task_group()
+ *        inherit_group()
+ *          inherit_event()
+ *            perf_event_alloc()
+ *              perf_init_event()
+ *                perf_try_init_event()	[ child , 1 ]
+ *
+ * While it appears there is an obvious deadlock here -- the parent and child
+ * nesting levels are inverted between the two. This is in fact safe because
+ * life-time rules separate them. That is an exiting task cannot fork, and a
+ * spawning task cannot (yet) exit.
+ *
+ * But remember that that these are parent<->child context relations, and
+ * migration does not affect children, therefore these two orderings should not
+ * interact.
  *
  * The change in perf_event::ctx does not affect children (as claimed above)
  * because the sys_perf_event_open() case will install a new event and break
@@ -3657,9 +3677,6 @@ static void perf_remove_from_owner(struct perf_event *event)
 	}
 }
 
-/*
- * Called when the last reference to the file is gone.
- */
 static void put_event(struct perf_event *event)
 {
 	struct perf_event_context *ctx;
@@ -3697,6 +3714,9 @@ int perf_event_release_kernel(struct perf_event *event)
 }
 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
 
+/*
+ * Called when the last reference to the file is gone.
+ */
 static int perf_release(struct inode *inode, struct file *file)
 {
 	put_event(file->private_data);
@@ -7364,7 +7384,12 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
 		return -ENODEV;
 
 	if (event->group_leader != event) {
-		ctx = perf_event_ctx_lock(event->group_leader);
+		/*
+		 * This ctx->mutex can nest when we're called through
+		 * inheritance. See the perf_event_ctx_lock_nested() comment.
+		 */
+		ctx = perf_event_ctx_lock_nested(event->group_leader,
+						 SINGLE_DEPTH_NESTING);
 		BUG_ON(!ctx);
 	}
 
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index b73279367087..b025295f4966 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -265,15 +265,17 @@ struct task_struct *rt_mutex_get_top_task(struct task_struct *task)
 }
 
 /*
- * Called by sched_setscheduler() to check whether the priority change
- * is overruled by a possible priority boosting.
+ * Called by sched_setscheduler() to get the priority which will be
+ * effective after the change.
  */
-int rt_mutex_check_prio(struct task_struct *task, int newprio)
+int rt_mutex_get_effective_prio(struct task_struct *task, int newprio)
 {
 	if (!task_has_pi_waiters(task))
-		return 0;
+		return newprio;
 
-	return task_top_pi_waiter(task)->task->prio <= newprio;
+	if (task_top_pi_waiter(task)->task->prio <= newprio)
+		return task_top_pi_waiter(task)->task->prio;
+	return newprio;
 }
 
 /*
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fe22f7510bce..123673291ffb 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3300,15 +3300,18 @@ static void __setscheduler_params(struct task_struct *p,
 
 /* Actually do priority change: must hold pi & rq lock. */
 static void __setscheduler(struct rq *rq, struct task_struct *p,
-			   const struct sched_attr *attr)
+			   const struct sched_attr *attr, bool keep_boost)
 {
 	__setscheduler_params(p, attr);
 
 	/*
-	 * If we get here, there was no pi waiters boosting the
-	 * task. It is safe to use the normal prio.
+	 * Keep a potential priority boosting if called from
+	 * sched_setscheduler().
 	 */
-	p->prio = normal_prio(p);
+	if (keep_boost)
+		p->prio = rt_mutex_get_effective_prio(p, normal_prio(p));
+	else
+		p->prio = normal_prio(p);
 
 	if (dl_prio(p->prio))
 		p->sched_class = &dl_sched_class;
@@ -3408,7 +3411,7 @@ static int __sched_setscheduler(struct task_struct *p,
 	int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 :
 		      MAX_RT_PRIO - 1 - attr->sched_priority;
 	int retval, oldprio, oldpolicy = -1, queued, running;
-	int policy = attr->sched_policy;
+	int new_effective_prio, policy = attr->sched_policy;
 	unsigned long flags;
 	const struct sched_class *prev_class;
 	struct rq *rq;
@@ -3590,15 +3593,14 @@ change:
 	oldprio = p->prio;
 
 	/*
-	 * Special case for priority boosted tasks.
-	 *
-	 * If the new priority is lower or equal (user space view)
-	 * than the current (boosted) priority, we just store the new
+	 * Take priority boosted tasks into account. If the new
+	 * effective priority is unchanged, we just store the new
 	 * normal parameters and do not touch the scheduler class and
 	 * the runqueue. This will be done when the task deboost
 	 * itself.
 	 */
-	if (rt_mutex_check_prio(p, newprio)) {
+	new_effective_prio = rt_mutex_get_effective_prio(p, newprio);
+	if (new_effective_prio == oldprio) {
 		__setscheduler_params(p, attr);
 		task_rq_unlock(rq, p, &flags);
 		return 0;
@@ -3612,7 +3614,7 @@ change:
 		put_prev_task(rq, p);
 
 	prev_class = p->sched_class;
-	__setscheduler(rq, p, attr);
+	__setscheduler(rq, p, attr, true);
 
 	if (running)
 		p->sched_class->set_curr_task(rq);
@@ -4387,10 +4389,7 @@ long __sched io_schedule_timeout(long timeout)
 	long ret;
 
 	current->in_iowait = 1;
-	if (old_iowait)
-		blk_schedule_flush_plug(current);
-	else
-		blk_flush_plug(current);
+	blk_schedule_flush_plug(current);
 
 	delayacct_blkio_start();
 	rq = raw_rq();
@@ -6997,27 +6996,23 @@ static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
 	unsigned long flags;
 	long cpu = (long)hcpu;
 	struct dl_bw *dl_b;
+	bool overflow;
+	int cpus;
 
-	switch (action & ~CPU_TASKS_FROZEN) {
+	switch (action) {
 	case CPU_DOWN_PREPARE:
-		/* explicitly allow suspend */
-		if (!(action & CPU_TASKS_FROZEN)) {
-			bool overflow;
-			int cpus;
-
-			rcu_read_lock_sched();
-			dl_b = dl_bw_of(cpu);
+		rcu_read_lock_sched();
+		dl_b = dl_bw_of(cpu);
 
-			raw_spin_lock_irqsave(&dl_b->lock, flags);
-			cpus = dl_bw_cpus(cpu);
-			overflow = __dl_overflow(dl_b, cpus, 0, 0);
-			raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+		raw_spin_lock_irqsave(&dl_b->lock, flags);
+		cpus = dl_bw_cpus(cpu);
+		overflow = __dl_overflow(dl_b, cpus, 0, 0);
+		raw_spin_unlock_irqrestore(&dl_b->lock, flags);
 
-			rcu_read_unlock_sched();
+		rcu_read_unlock_sched();
 
-			if (overflow)
-				return notifier_from_errno(-EBUSY);
-		}
+		if (overflow)
+			return notifier_from_errno(-EBUSY);
 		cpuset_update_active_cpus(false);
 		break;
 	case CPU_DOWN_PREPARE_FROZEN:
@@ -7346,7 +7341,7 @@ static void normalize_task(struct rq *rq, struct task_struct *p)
 	queued = task_on_rq_queued(p);
 	if (queued)
 		dequeue_task(rq, p, 0);
-	__setscheduler(rq, p, &attr);
+	__setscheduler(rq, p, &attr, false);
 	if (queued) {
 		enqueue_task(rq, p, 0);
 		resched_curr(rq);
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 2316f50b07a4..581a68a04c64 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -41,6 +41,8 @@
 #define NMI_WATCHDOG_ENABLED      (1 << NMI_WATCHDOG_ENABLED_BIT)
 #define SOFT_WATCHDOG_ENABLED     (1 << SOFT_WATCHDOG_ENABLED_BIT)
 
+static DEFINE_MUTEX(watchdog_proc_mutex);
+
 #ifdef CONFIG_HARDLOCKUP_DETECTOR
 static unsigned long __read_mostly watchdog_enabled = SOFT_WATCHDOG_ENABLED|NMI_WATCHDOG_ENABLED;
 #else
@@ -608,26 +610,36 @@ void watchdog_nmi_enable_all(void)
 {
 	int cpu;
 
-	if (!watchdog_user_enabled)
-		return;
+	mutex_lock(&watchdog_proc_mutex);
+
+	if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
+		goto unlock;
 
 	get_online_cpus();
 	for_each_online_cpu(cpu)
 		watchdog_nmi_enable(cpu);
 	put_online_cpus();
+
+unlock:
+	mutex_unlock(&watchdog_proc_mutex);
 }
 
 void watchdog_nmi_disable_all(void)
 {
 	int cpu;
 
+	mutex_lock(&watchdog_proc_mutex);
+
 	if (!watchdog_running)
-		return;
+		goto unlock;
 
 	get_online_cpus();
 	for_each_online_cpu(cpu)
 		watchdog_nmi_disable(cpu);
 	put_online_cpus();
+
+unlock:
+	mutex_unlock(&watchdog_proc_mutex);
 }
 #else
 static int watchdog_nmi_enable(unsigned int cpu) { return 0; }
@@ -744,8 +756,6 @@ static int proc_watchdog_update(void)
 
 }
 
-static DEFINE_MUTEX(watchdog_proc_mutex);
-
 /*
  * common function for watchdog, nmi_watchdog and soft_watchdog parameter
  *