KVM: switch coalesced mmio changes to slots_lock
Michael S. Tsirkin [Mon, 29 Jun 2009 19:24:14 +0000 (22:24 +0300)]
switch coalesced mmio slots_lock.  slots_lock is already taken for read
everywhere, so we only need to take it for write when changing zones.
This is in preparation to removing in_range and kvm->lock around it.

[avi: fix build]

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

virt/kvm/coalesced_mmio.c

index 397f419..b40946c 100644 (file)
@@ -115,16 +115,16 @@ int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
        if (dev == NULL)
                return -EINVAL;
 
-       mutex_lock(&kvm->lock);
+       down_write(&kvm->slots_lock);
        if (dev->nb_zones >= KVM_COALESCED_MMIO_ZONE_MAX) {
-               mutex_unlock(&kvm->lock);
+               up_write(&kvm->slots_lock);
                return -ENOBUFS;
        }
 
        dev->zone[dev->nb_zones] = *zone;
        dev->nb_zones++;
 
-       mutex_unlock(&kvm->lock);
+       up_write(&kvm->slots_lock);
        return 0;
 }
 
@@ -138,7 +138,7 @@ int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
        if (dev == NULL)
                return -EINVAL;
 
-       mutex_lock(&kvm->lock);
+       down_write(&kvm->slots_lock);
 
        i = dev->nb_zones;
        while(i) {
@@ -156,7 +156,7 @@ int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
                i--;
        }
 
-       mutex_unlock(&kvm->lock);
+       up_write(&kvm->slots_lock);
 
        return 0;
 }