Merge tag 'spi-nor/for-6.3' into mtd/next

SPI NOR changes:
* small fixes on core and spansion driver.

4 files changed, 73 insertions, 53 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index eacc3702654d..d56328e5080e 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -380,7 +380,6 @@ enum event_type_t {
 
 /*
  * perf_sched_events : >0 events exist
- * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
  */
 
 static void perf_sched_delayed(struct work_struct *work);
@@ -389,7 +388,6 @@ static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
 static DEFINE_MUTEX(perf_sched_mutex);
 static atomic_t perf_sched_count;
 
-static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
 
 static atomic_t nr_mmap_events __read_mostly;
@@ -844,9 +842,16 @@ static void perf_cgroup_switch(struct task_struct *task)
 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
 	struct perf_cgroup *cgrp;
 
-	cgrp = perf_cgroup_from_task(task, NULL);
+	/*
+	 * cpuctx->cgrp is set when the first cgroup event enabled,
+	 * and is cleared when the last cgroup event disabled.
+	 */
+	if (READ_ONCE(cpuctx->cgrp) == NULL)
+		return;
 
 	WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
+
+	cgrp = perf_cgroup_from_task(task, NULL);
 	if (READ_ONCE(cpuctx->cgrp) == cgrp)
 		return;
 
@@ -3631,8 +3636,7 @@ void __perf_event_task_sched_out(struct task_struct *task,
 	 * to check if we have to switch out PMU state.
 	 * cgroup event are system-wide mode only
 	 */
-	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
-		perf_cgroup_switch(next);
+	perf_cgroup_switch(next);
 }
 
 static bool perf_less_group_idx(const void *l, const void *r)
@@ -4974,15 +4978,6 @@ static void unaccount_pmu_sb_event(struct perf_event *event)
 		detach_sb_event(event);
 }
 
-static void unaccount_event_cpu(struct perf_event *event, int cpu)
-{
-	if (event->parent)
-		return;
-
-	if (is_cgroup_event(event))
-		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
-}
-
 #ifdef CONFIG_NO_HZ_FULL
 static DEFINE_SPINLOCK(nr_freq_lock);
 #endif
@@ -5048,8 +5043,6 @@ static void unaccount_event(struct perf_event *event)
 			schedule_delayed_work(&perf_sched_work, HZ);
 	}
 
-	unaccount_event_cpu(event, event->cpu);
-
 	unaccount_pmu_sb_event(event);
 }
 
@@ -11679,15 +11672,6 @@ static void account_pmu_sb_event(struct perf_event *event)
 		attach_sb_event(event);
 }
 
-static void account_event_cpu(struct perf_event *event, int cpu)
-{
-	if (event->parent)
-		return;
-
-	if (is_cgroup_event(event))
-		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
-}
-
 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
 static void account_freq_event_nohz(void)
 {
@@ -11775,8 +11759,6 @@ static void account_event(struct perf_event *event)
 	}
 enabled:
 
-	account_event_cpu(event, event->cpu);
-
 	account_pmu_sb_event(event);
 }
 
@@ -12339,12 +12321,12 @@ SYSCALL_DEFINE5(perf_event_open,
 	if (flags & ~PERF_FLAG_ALL)
 		return -EINVAL;
 
-	/* Do we allow access to perf_event_open(2) ? */
-	err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
+	err = perf_copy_attr(attr_uptr, &attr);
 	if (err)
 		return err;
 
-	err = perf_copy_attr(attr_uptr, &attr);
+	/* Do we allow access to perf_event_open(2) ? */
+	err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
 	if (err)
 		return err;
 
@@ -12689,7 +12671,8 @@ SYSCALL_DEFINE5(perf_event_open,
 	return event_fd;
 
 err_context:
-	/* event->pmu_ctx freed by free_event() */
+	put_pmu_ctx(event->pmu_ctx);
+	event->pmu_ctx = NULL; /* _free_event() */
 err_locked:
 	mutex_unlock(&ctx->mutex);
 	perf_unpin_context(ctx);
@@ -12802,6 +12785,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
 
 err_pmu_ctx:
 	put_pmu_ctx(pmu_ctx);
+	event->pmu_ctx = NULL; /* _free_event() */
 err_unlock:
 	mutex_unlock(&ctx->mutex);
 	perf_unpin_context(ctx);
@@ -12822,13 +12806,11 @@ static void __perf_pmu_remove(struct perf_event_context *ctx,
 
 	perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) {
 		perf_remove_from_context(event, 0);
-		unaccount_event_cpu(event, cpu);
 		put_pmu_ctx(event->pmu_ctx);
 		list_add(&event->migrate_entry, events);
 
 		for_each_sibling_event(sibling, event) {
 			perf_remove_from_context(sibling, 0);
-			unaccount_event_cpu(sibling, cpu);
 			put_pmu_ctx(sibling->pmu_ctx);
 			list_add(&sibling->migrate_entry, events);
 		}
@@ -12847,7 +12829,6 @@ static void __perf_pmu_install_event(struct pmu *pmu,
 
 	if (event->state >= PERF_EVENT_STATE_OFF)
 		event->state = PERF_EVENT_STATE_INACTIVE;
-	account_event_cpu(event, cpu);
 	perf_install_in_context(ctx, event, cpu);
 }
 
@@ -13231,7 +13212,7 @@ inherit_event(struct perf_event *parent_event,
 	pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event);
 	if (IS_ERR(pmu_ctx)) {
 		free_event(child_event);
-		return NULL;
+		return ERR_CAST(pmu_ctx);
 	}
 	child_event->pmu_ctx = pmu_ctx;
 
@@ -13742,8 +13723,7 @@ static int __perf_cgroup_move(void *info)
 	struct task_struct *task = info;
 
 	preempt_disable();
-	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
-		perf_cgroup_switch(task);
+	perf_cgroup_switch(task);
 	preempt_enable();
 
 	return 0;
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
index 086a22d1adb7..a8074079b09e 100644
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -286,19 +286,22 @@ SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user *, waiters,
 	}
 
 	futexv = kcalloc(nr_futexes, sizeof(*futexv), GFP_KERNEL);
-	if (!futexv)
-		return -ENOMEM;
+	if (!futexv) {
+		ret = -ENOMEM;
+		goto destroy_timer;
+	}
 
 	ret = futex_parse_waitv(futexv, waiters, nr_futexes);
 	if (!ret)
 		ret = futex_wait_multiple(futexv, nr_futexes, timeout ? &to : NULL);
 
+	kfree(futexv);
+
+destroy_timer:
 	if (timeout) {
 		hrtimer_cancel(&to.timer);
 		destroy_hrtimer_on_stack(&to.timer);
 	}
-
-	kfree(futexv);
 	return ret;
 }
 
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 7779ee8abc2a..010cf4e6d0b8 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -89,15 +89,31 @@ static inline int __ww_mutex_check_kill(struct rt_mutex *lock,
  * set this bit before looking at the lock.
  */
 
-static __always_inline void
-rt_mutex_set_owner(struct rt_mutex_base *lock, struct task_struct *owner)
+static __always_inline struct task_struct *
+rt_mutex_owner_encode(struct rt_mutex_base *lock, struct task_struct *owner)
 {
 	unsigned long val = (unsigned long)owner;
 
 	if (rt_mutex_has_waiters(lock))
 		val |= RT_MUTEX_HAS_WAITERS;
 
-	WRITE_ONCE(lock->owner, (struct task_struct *)val);
+	return (struct task_struct *)val;
+}
+
+static __always_inline void
+rt_mutex_set_owner(struct rt_mutex_base *lock, struct task_struct *owner)
+{
+	/*
+	 * lock->wait_lock is held but explicit acquire semantics are needed
+	 * for a new lock owner so WRITE_ONCE is insufficient.
+	 */
+	xchg_acquire(&lock->owner, rt_mutex_owner_encode(lock, owner));
+}
+
+static __always_inline void rt_mutex_clear_owner(struct rt_mutex_base *lock)
+{
+	/* lock->wait_lock is held so the unlock provides release semantics. */
+	WRITE_ONCE(lock->owner, rt_mutex_owner_encode(lock, NULL));
 }
 
 static __always_inline void clear_rt_mutex_waiters(struct rt_mutex_base *lock)
@@ -106,7 +122,8 @@ static __always_inline void clear_rt_mutex_waiters(struct rt_mutex_base *lock)
 			((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
 }
 
-static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex_base *lock)
+static __always_inline void
+fixup_rt_mutex_waiters(struct rt_mutex_base *lock, bool acquire_lock)
 {
 	unsigned long owner, *p = (unsigned long *) &lock->owner;
 
@@ -172,8 +189,21 @@ static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex_base *lock)
 	 * still set.
 	 */
 	owner = READ_ONCE(*p);
-	if (owner & RT_MUTEX_HAS_WAITERS)
-		WRITE_ONCE(*p, owner & ~RT_MUTEX_HAS_WAITERS);
+	if (owner & RT_MUTEX_HAS_WAITERS) {
+		/*
+		 * See rt_mutex_set_owner() and rt_mutex_clear_owner() on
+		 * why xchg_acquire() is used for updating owner for
+		 * locking and WRITE_ONCE() for unlocking.
+		 *
+		 * WRITE_ONCE() would work for the acquire case too, but
+		 * in case that the lock acquisition failed it might
+		 * force other lockers into the slow path unnecessarily.
+		 */
+		if (acquire_lock)
+			xchg_acquire(p, owner & ~RT_MUTEX_HAS_WAITERS);
+		else
+			WRITE_ONCE(*p, owner & ~RT_MUTEX_HAS_WAITERS);
+	}
 }
 
 /*
@@ -208,6 +238,13 @@ static __always_inline void mark_rt_mutex_waiters(struct rt_mutex_base *lock)
 		owner = *p;
 	} while (cmpxchg_relaxed(p, owner,
 				 owner | RT_MUTEX_HAS_WAITERS) != owner);
+
+	/*
+	 * The cmpxchg loop above is relaxed to avoid back-to-back ACQUIRE
+	 * operations in the event of contention. Ensure the successful
+	 * cmpxchg is visible.
+	 */
+	smp_mb__after_atomic();
 }
 
 /*
@@ -1243,7 +1280,7 @@ static int __sched __rt_mutex_slowtrylock(struct rt_mutex_base *lock)
 	 * try_to_take_rt_mutex() sets the lock waiters bit
 	 * unconditionally. Clean this up.
 	 */
-	fixup_rt_mutex_waiters(lock);
+	fixup_rt_mutex_waiters(lock, true);
 
 	return ret;
 }
@@ -1604,7 +1641,7 @@ static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock,
 	 * try_to_take_rt_mutex() sets the waiter bit
 	 * unconditionally. We might have to fix that up.
 	 */
-	fixup_rt_mutex_waiters(lock);
+	fixup_rt_mutex_waiters(lock, true);
 
 	trace_contention_end(lock, ret);
 
@@ -1719,7 +1756,7 @@ static void __sched rtlock_slowlock_locked(struct rt_mutex_base *lock)
 	 * try_to_take_rt_mutex() sets the waiter bit unconditionally.
 	 * We might have to fix that up:
 	 */
-	fixup_rt_mutex_waiters(lock);
+	fixup_rt_mutex_waiters(lock, true);
 	debug_rt_mutex_free_waiter(&waiter);
 
 	trace_contention_end(lock, 0);
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
index 900220941caa..cb9fdff76a8a 100644
--- a/kernel/locking/rtmutex_api.c
+++ b/kernel/locking/rtmutex_api.c
@@ -267,7 +267,7 @@ void __sched rt_mutex_init_proxy_locked(struct rt_mutex_base *lock,
 void __sched rt_mutex_proxy_unlock(struct rt_mutex_base *lock)
 {
 	debug_rt_mutex_proxy_unlock(lock);
-	rt_mutex_set_owner(lock, NULL);
+	rt_mutex_clear_owner(lock);
 }
 
 /**
@@ -382,7 +382,7 @@ int __sched rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock,
 	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
 	 * have to fix that up.
 	 */
-	fixup_rt_mutex_waiters(lock);
+	fixup_rt_mutex_waiters(lock, true);
 	raw_spin_unlock_irq(&lock->wait_lock);
 
 	return ret;
@@ -438,7 +438,7 @@ bool __sched rt_mutex_cleanup_proxy_lock(struct rt_mutex_base *lock,
 	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
 	 * have to fix that up.
 	 */
-	fixup_rt_mutex_waiters(lock);
+	fixup_rt_mutex_waiters(lock, false);
 
 	raw_spin_unlock_irq(&lock->wait_lock);