ringtest: commonize implementation of poll_avail/poll_used

[cascardo/linux.git] / tools / virtio / ringtest / virtio_ring_0_9.c

diff --git a/tools/virtio/ringtest/virtio_ring_0_9.c b/tools/virtio/ringtest/virtio_ring_0_9.c
index 7618662..bbc3043 100644 (file)
--- a/tools/virtio/ringtest/virtio_ring_0_9.c
+++ b/tools/virtio/ringtest/virtio_ring_0_9.c
@@ -194,24 +194,16 @@ void *get_buf(unsigned *lenp, void **bufp)
        return datap;
 }
 
-void poll_used(void)
+bool used_empty()
 {
+       unsigned short last_used_idx = guest.last_used_idx;
 #ifdef RING_POLL
-       unsigned head = (ring_size - 1) & guest.last_used_idx;
+       unsigned short head = last_used_idx & (ring_size - 1);
+       unsigned index = ring.used->ring[head].id;
 
-       for (;;) {
-               unsigned index = ring.used->ring[head].id;
-
-               if ((index ^ guest.last_used_idx ^ 0x8000) & ~(ring_size - 1))
-                       busy_wait();
-               else
-                       break;
-       }
+       return (index ^ last_used_idx ^ 0x8000) & ~(ring_size - 1);
 #else
-       unsigned head = guest.last_used_idx;
-
-       while (ring.used->idx == head)
-               busy_wait();
+       return ring.used->idx == last_used_idx;
 #endif
 }
 
@@ -224,22 +216,11 @@ void disable_call()
 
 bool enable_call()
 {
-       unsigned short last_used_idx;
-
-       vring_used_event(&ring) = (last_used_idx = guest.last_used_idx);
+       vring_used_event(&ring) = guest.last_used_idx;
        /* Flush call index write */
        /* Barrier D (for pairing) */
        smp_mb();
-#ifdef RING_POLL
-       {
-               unsigned short head = last_used_idx & (ring_size - 1);
-               unsigned index = ring.used->ring[head].id;
-
-               return (index ^ last_used_idx ^ 0x8000) & ~(ring_size - 1);
-       }
-#else
-       return ring.used->idx == last_used_idx;
-#endif
+       return used_empty();
 }
 
 void kick_available(void)
@@ -266,36 +247,21 @@ void disable_kick()
 
 bool enable_kick()
 {
-       unsigned head = host.used_idx;
-
-       vring_avail_event(&ring) = head;
+       vring_avail_event(&ring) = host.used_idx;
        /* Barrier C (for pairing) */
        smp_mb();
-#ifdef RING_POLL
-       {
-               unsigned index = ring.avail->ring[head & (ring_size - 1)];
-
-               return (index ^ head ^ 0x8000) & ~(ring_size - 1);
-       }
-#else
-       return head == ring.avail->idx;
-#endif
+       return avail_empty();
 }
 
-void poll_avail(void)
+bool avail_empty()
 {
        unsigned head = host.used_idx;
 #ifdef RING_POLL
-       for (;;) {
-               unsigned index = ring.avail->ring[head & (ring_size - 1)];
-               if ((index ^ head ^ 0x8000) & ~(ring_size - 1))
-                       busy_wait();
-               else
-                       break;
-       }
+       unsigned index = ring.avail->ring[head & (ring_size - 1)];
+
+       return ((index ^ head ^ 0x8000) & ~(ring_size - 1));
 #else
-       while (ring.avail->idx == head)
-               busy_wait();
+       return head == ring.avail->idx;
 #endif
 }