Merge tag 'v3.16-rc4' into drm-intel-next-queued

Due to Dave's vacation drm-next hasn't opened yet for 3.17 so I
couldn't move my drm-intel-next queue forward yet like I usually do.
Just pull in the latest upstream -rc to unblock patch merging - I
don't want to needlessly rebase my current patch pile really and void
all the testing we've done already.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 87 insertions, 70 deletions

diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index f709983f41f..5b0e445bc3f 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -26,83 +26,81 @@ __setup("spin_retry=", spin_retry_setup);
 
 void arch_spin_lock_wait(arch_spinlock_t *lp)
 {
-	int count = spin_retry;
-	unsigned int cpu = ~smp_processor_id();
+	unsigned int cpu = SPINLOCK_LOCKVAL;
 	unsigned int owner;
+	int count;
 
 	while (1) {
-		owner = lp->owner_cpu;
-		if (!owner || smp_vcpu_scheduled(~owner)) {
-			for (count = spin_retry; count > 0; count--) {
-				if (arch_spin_is_locked(lp))
-					continue;
-				if (_raw_compare_and_swap(&lp->owner_cpu, 0,
-							  cpu) == 0)
-					return;
-			}
-			if (MACHINE_IS_LPAR)
-				continue;
+		owner = ACCESS_ONCE(lp->lock);
+		/* Try to get the lock if it is free. */
+		if (!owner) {
+			if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+				return;
+			continue;
 		}
-		owner = lp->owner_cpu;
-		if (owner)
+		/* Check if the lock owner is running. */
+		if (!smp_vcpu_scheduled(~owner)) {
+			smp_yield_cpu(~owner);
+			continue;
+		}
+		/* Loop for a while on the lock value. */
+		count = spin_retry;
+		do {
+			owner = ACCESS_ONCE(lp->lock);
+		} while (owner && count-- > 0);
+		if (!owner)
+			continue;
+		/*
+		 * For multiple layers of hypervisors, e.g. z/VM + LPAR
+		 * yield the CPU if the lock is still unavailable.
+		 */
+		if (!MACHINE_IS_LPAR)
 			smp_yield_cpu(~owner);
-		if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
-			return;
 	}
 }
 EXPORT_SYMBOL(arch_spin_lock_wait);
 
 void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
 {
-	int count = spin_retry;
-	unsigned int cpu = ~smp_processor_id();
+	unsigned int cpu = SPINLOCK_LOCKVAL;
 	unsigned int owner;
+	int count;
 
 	local_irq_restore(flags);
 	while (1) {
-		owner = lp->owner_cpu;
-		if (!owner || smp_vcpu_scheduled(~owner)) {
-			for (count = spin_retry; count > 0; count--) {
-				if (arch_spin_is_locked(lp))
-					continue;
-				local_irq_disable();
-				if (_raw_compare_and_swap(&lp->owner_cpu, 0,
-							  cpu) == 0)
-					return;
-				local_irq_restore(flags);
-			}
-			if (MACHINE_IS_LPAR)
-				continue;
+		owner = ACCESS_ONCE(lp->lock);
+		/* Try to get the lock if it is free. */
+		if (!owner) {
+			local_irq_disable();
+			if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+				return;
+			local_irq_restore(flags);
 		}
-		owner = lp->owner_cpu;
-		if (owner)
+		/* Check if the lock owner is running. */
+		if (!smp_vcpu_scheduled(~owner)) {
 			smp_yield_cpu(~owner);
-		local_irq_disable();
-		if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
-			return;
-		local_irq_restore(flags);
-	}
-}
-EXPORT_SYMBOL(arch_spin_lock_wait_flags);
-
-int arch_spin_trylock_retry(arch_spinlock_t *lp)
-{
-	unsigned int cpu = ~smp_processor_id();
-	int count;
-
-	for (count = spin_retry; count > 0; count--) {
-		if (arch_spin_is_locked(lp))
 			continue;
-		if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
-			return 1;
+		}
+		/* Loop for a while on the lock value. */
+		count = spin_retry;
+		do {
+			owner = ACCESS_ONCE(lp->lock);
+		} while (owner && count-- > 0);
+		if (!owner)
+			continue;
+		/*
+		 * For multiple layers of hypervisors, e.g. z/VM + LPAR
+		 * yield the CPU if the lock is still unavailable.
+		 */
+		if (!MACHINE_IS_LPAR)
+			smp_yield_cpu(~owner);
 	}
-	return 0;
 }
-EXPORT_SYMBOL(arch_spin_trylock_retry);
+EXPORT_SYMBOL(arch_spin_lock_wait_flags);
 
-void arch_spin_relax(arch_spinlock_t *lock)
+void arch_spin_relax(arch_spinlock_t *lp)
 {
-	unsigned int cpu = lock->owner_cpu;
+	unsigned int cpu = lp->lock;
 	if (cpu != 0) {
 		if (MACHINE_IS_VM || MACHINE_IS_KVM ||
 		    !smp_vcpu_scheduled(~cpu))
@@ -111,6 +109,17 @@ void arch_spin_relax(arch_spinlock_t *lock)
 }
 EXPORT_SYMBOL(arch_spin_relax);
 
+int arch_spin_trylock_retry(arch_spinlock_t *lp)
+{
+	int count;
+
+	for (count = spin_retry; count > 0; count--)
+		if (arch_spin_trylock_once(lp))
+			return 1;
+	return 0;
+}
+EXPORT_SYMBOL(arch_spin_trylock_retry);
+
 void _raw_read_lock_wait(arch_rwlock_t *rw)
 {
 	unsigned int old;
@@ -121,10 +130,10 @@ void _raw_read_lock_wait(arch_rwlock_t *rw)
 			smp_yield();
 			count = spin_retry;
 		}
-		if (!arch_read_can_lock(rw))
+		old = ACCESS_ONCE(rw->lock);
+		if ((int) old < 0)
 			continue;
-		old = rw->lock & 0x7fffffffU;
-		if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
+		if (_raw_compare_and_swap(&rw->lock, old, old + 1))
 			return;
 	}
 }
@@ -141,12 +150,13 @@ void _raw_read_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
 			smp_yield();
 			count = spin_retry;
 		}
-		if (!arch_read_can_lock(rw))
+		old = ACCESS_ONCE(rw->lock);
+		if ((int) old < 0)
 			continue;
-		old = rw->lock & 0x7fffffffU;
 		local_irq_disable();
-		if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
+		if (_raw_compare_and_swap(&rw->lock, old, old + 1))
 			return;
+		local_irq_restore(flags);
 	}
 }
 EXPORT_SYMBOL(_raw_read_lock_wait_flags);
@@ -157,10 +167,10 @@ int _raw_read_trylock_retry(arch_rwlock_t *rw)
 	int count = spin_retry;
 
 	while (count-- > 0) {
-		if (!arch_read_can_lock(rw))
+		old = ACCESS_ONCE(rw->lock);
+		if ((int) old < 0)
 			continue;
-		old = rw->lock & 0x7fffffffU;
-		if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
+		if (_raw_compare_and_swap(&rw->lock, old, old + 1))
 			return 1;
 	}
 	return 0;
@@ -169,6 +179,7 @@ EXPORT_SYMBOL(_raw_read_trylock_retry);
 
 void _raw_write_lock_wait(arch_rwlock_t *rw)
 {
+	unsigned int old;
 	int count = spin_retry;
 
 	while (1) {
@@ -176,9 +187,10 @@ void _raw_write_lock_wait(arch_rwlock_t *rw)
 			smp_yield();
 			count = spin_retry;
 		}
-		if (!arch_write_can_lock(rw))
+		old = ACCESS_ONCE(rw->lock);
+		if (old)
 			continue;
-		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
+		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
 			return;
 	}
 }
@@ -186,6 +198,7 @@ EXPORT_SYMBOL(_raw_write_lock_wait);
 
 void _raw_write_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
 {
+	unsigned int old;
 	int count = spin_retry;
 
 	local_irq_restore(flags);
@@ -194,23 +207,27 @@ void _raw_write_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
 			smp_yield();
 			count = spin_retry;
 		}
-		if (!arch_write_can_lock(rw))
+		old = ACCESS_ONCE(rw->lock);
+		if (old)
 			continue;
 		local_irq_disable();
-		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
+		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
 			return;
+		local_irq_restore(flags);
 	}
 }
 EXPORT_SYMBOL(_raw_write_lock_wait_flags);
 
 int _raw_write_trylock_retry(arch_rwlock_t *rw)
 {
+	unsigned int old;
 	int count = spin_retry;
 
 	while (count-- > 0) {
-		if (!arch_write_can_lock(rw))
+		old = ACCESS_ONCE(rw->lock);
+		if (old)
 			continue;
-		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
+		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
 			return 1;
 	}
 	return 0;