--- zzzz-none-000/linux-3.10.107/arch/s390/lib/spinlock.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/s390/lib/spinlock.c	2021-02-04 17:41:59.000000000 +0000
@@ -12,7 +12,15 @@
 #include <linux/smp.h>
 #include <asm/io.h>
 
-int spin_retry = 1000;
+int spin_retry = -1;
+
+static int __init spin_retry_init(void)
+{
+	if (spin_retry < 0)
+		spin_retry = MACHINE_HAS_CAD ? 10 : 1000;
+	return 0;
+}
+early_initcall(spin_retry_init);
 
 /**
  * spin_retry= parameter
@@ -24,132 +32,135 @@
 }
 __setup("spin_retry=", spin_retry_setup);
 
+static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old)
+{
+	asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock));
+}
+
 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 {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&lp->lock, owner);
+			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);
+			continue;
+		}
+		/* Loop for a while on the lock value. */
+		count = spin_retry;
+		do {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&lp->lock, owner);
+			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);
-		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();
+	unsigned int cpu = SPINLOCK_LOCKVAL;
+	unsigned int owner;
 	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;
+		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 1;
+		} else if (MACHINE_HAS_CAD)
+			_raw_compare_and_delay(&lp->lock, owner);
 	}
 	return 0;
 }
 EXPORT_SYMBOL(arch_spin_trylock_retry);
 
-void arch_spin_relax(arch_spinlock_t *lock)
-{
-	unsigned int cpu = lock->owner_cpu;
-	if (cpu != 0) {
-		if (MACHINE_IS_VM || MACHINE_IS_KVM ||
-		    !smp_vcpu_scheduled(~cpu))
-			smp_yield_cpu(~cpu);
-	}
-}
-EXPORT_SYMBOL(arch_spin_relax);
-
 void _raw_read_lock_wait(arch_rwlock_t *rw)
 {
-	unsigned int old;
+	unsigned int owner, old;
 	int count = spin_retry;
 
+#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
+	__RAW_LOCK(&rw->lock, -1, __RAW_OP_ADD);
+#endif
+	owner = 0;
 	while (1) {
 		if (count-- <= 0) {
-			smp_yield();
+			if (owner && !smp_vcpu_scheduled(~owner))
+				smp_yield_cpu(~owner);
 			count = spin_retry;
 		}
-		if (!arch_read_can_lock(rw))
+		old = ACCESS_ONCE(rw->lock);
+		owner = ACCESS_ONCE(rw->owner);
+		if ((int) old < 0) {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&rw->lock, old);
 			continue;
-		old = rw->lock & 0x7fffffffU;
-		if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
-			return;
-	}
-}
-EXPORT_SYMBOL(_raw_read_lock_wait);
-
-void _raw_read_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
-{
-	unsigned int old;
-	int count = spin_retry;
-
-	local_irq_restore(flags);
-	while (1) {
-		if (count-- <= 0) {
-			smp_yield();
-			count = spin_retry;
 		}
-		if (!arch_read_can_lock(rw))
-			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;
 	}
 }
-EXPORT_SYMBOL(_raw_read_lock_wait_flags);
+EXPORT_SYMBOL(_raw_read_lock_wait);
 
 int _raw_read_trylock_retry(arch_rwlock_t *rw)
 {
@@ -157,62 +168,105 @@
 	int count = spin_retry;
 
 	while (count-- > 0) {
-		if (!arch_read_can_lock(rw))
+		old = ACCESS_ONCE(rw->lock);
+		if ((int) old < 0) {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&rw->lock, old);
 			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;
 }
 EXPORT_SYMBOL(_raw_read_trylock_retry);
 
-void _raw_write_lock_wait(arch_rwlock_t *rw)
+#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
+
+void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev)
 {
+	unsigned int owner, old;
 	int count = spin_retry;
 
+	owner = 0;
 	while (1) {
 		if (count-- <= 0) {
-			smp_yield();
+			if (owner && !smp_vcpu_scheduled(~owner))
+				smp_yield_cpu(~owner);
 			count = spin_retry;
 		}
-		if (!arch_write_can_lock(rw))
-			continue;
-		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
-			return;
+		old = ACCESS_ONCE(rw->lock);
+		owner = ACCESS_ONCE(rw->owner);
+		smp_mb();
+		if ((int) old >= 0) {
+			prev = __RAW_LOCK(&rw->lock, 0x80000000, __RAW_OP_OR);
+			old = prev;
+		}
+		if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
+			break;
+		if (MACHINE_HAS_CAD)
+			_raw_compare_and_delay(&rw->lock, old);
 	}
 }
 EXPORT_SYMBOL(_raw_write_lock_wait);
 
-void _raw_write_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
+#else /* CONFIG_HAVE_MARCH_Z196_FEATURES */
+
+void _raw_write_lock_wait(arch_rwlock_t *rw)
 {
+	unsigned int owner, old, prev;
 	int count = spin_retry;
 
-	local_irq_restore(flags);
+	prev = 0x80000000;
+	owner = 0;
 	while (1) {
 		if (count-- <= 0) {
-			smp_yield();
+			if (owner && !smp_vcpu_scheduled(~owner))
+				smp_yield_cpu(~owner);
 			count = spin_retry;
 		}
-		if (!arch_write_can_lock(rw))
-			continue;
-		local_irq_disable();
-		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
-			return;
+		old = ACCESS_ONCE(rw->lock);
+		owner = ACCESS_ONCE(rw->owner);
+		if ((int) old >= 0 &&
+		    _raw_compare_and_swap(&rw->lock, old, old | 0x80000000))
+			prev = old;
+		else
+			smp_mb();
+		if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
+			break;
+		if (MACHINE_HAS_CAD)
+			_raw_compare_and_delay(&rw->lock, old);
 	}
 }
-EXPORT_SYMBOL(_raw_write_lock_wait_flags);
+EXPORT_SYMBOL(_raw_write_lock_wait);
+
+#endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */
 
 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) {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&rw->lock, 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;
 }
 EXPORT_SYMBOL(_raw_write_trylock_retry);
+
+void arch_lock_relax(unsigned int cpu)
+{
+	if (!cpu)
+		return;
+	if (MACHINE_IS_LPAR && smp_vcpu_scheduled(~cpu))
+		return;
+	smp_yield_cpu(~cpu);
+}
+EXPORT_SYMBOL(arch_lock_relax);