[S390] spinlock: check virtual cpu running status

[safe/jmp/linux-2.6] / arch / s390 / lib / spinlock.c

diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index cff327f..91754ff 100644 (file)
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -43,16 +43,24 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
 {
        int count = spin_retry;
        unsigned int cpu = ~smp_processor_id();
+       unsigned int owner;
 
        while (1) {
-               if (count-- <= 0) {
-                       unsigned int owner = lp->owner_cpu;
-                       if (owner != 0)
-                               _raw_yield_cpu(~owner);
-                       count = spin_retry;
+               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;
                }
-               if (arch_spin_is_locked(lp))
-                       continue;
+               owner = lp->owner_cpu;
+               if (owner)
+                       _raw_yield_cpu(~owner);
                if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
                        return;
        }
@@ -63,17 +71,27 @@ 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 owner;
 
        local_irq_restore(flags);
        while (1) {
-               if (count-- <= 0) {
-                       unsigned int owner = lp->owner_cpu;
-                       if (owner != 0)
-                               _raw_yield_cpu(~owner);
-                       count = spin_retry;
+               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;
                }
-               if (arch_spin_is_locked(lp))
-                       continue;
+               owner = lp->owner_cpu;
+               if (owner)
+                       _raw_yield_cpu(~owner);
                local_irq_disable();
                if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
                        return;
@@ -100,8 +118,11 @@ EXPORT_SYMBOL(arch_spin_trylock_retry);
 void arch_spin_relax(arch_spinlock_t *lock)
 {
        unsigned int cpu = lock->owner_cpu;
-       if (cpu != 0)
-               _raw_yield_cpu(~cpu);
+       if (cpu != 0) {
+               if (MACHINE_IS_VM || MACHINE_IS_KVM ||
+                   !smp_vcpu_scheduled(~cpu))
+                       _raw_yield_cpu(~cpu);
+       }
 }
 EXPORT_SYMBOL(arch_spin_relax);