1 files changed, 5 insertions, 5 deletions

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index c4c7ec2f9d30..754906800999 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -24,7 +24,8 @@ static int coalesced_mmio_in_range(struct kvm_io_device *this,
 {
         struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
         struct kvm_coalesced_mmio_zone *zone;
-        int next;
+        struct kvm_coalesced_mmio_ring *ring;
+        unsigned avail;
         int i;
 
         if (!is_write)
@@ -40,10 +41,9 @@ static int coalesced_mmio_in_range(struct kvm_io_device *this,
          * check if we don't meet the first used entry
          * there is always one unused entry in the buffer
          */
-
-        next = (dev->kvm->coalesced_mmio_ring->last + 1) %
-                                                        KVM_COALESCED_MMIO_MAX;
-        if (next == dev->kvm->coalesced_mmio_ring->first) {
+        ring = dev->kvm->coalesced_mmio_ring;
+        avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX;
+        if (avail < 1) {
                 /* full */
                 return 0;
         }