net: tap: use qemu_set_nonblock

[mirror_qemu.git] / net / netmap.c

diff --git a/net/netmap.c b/net/netmap.c
index 71a8122bdd90c6146452ce646ad393f3aece4f28..0cc8f545c5c02cf0b3f5b9f6642e1a1f262529a9 100644 (file)
--- a/net/netmap.c
+++ b/net/netmap.c
@@ -154,65 +154,27 @@ static void netmap_writable(void *opaque)
     qemu_flush_queued_packets(&s->nc);
 }
 
-static ssize_t netmap_receive(NetClientState *nc,
-      const uint8_t *buf, size_t size)
-{
-    NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
-    struct netmap_ring *ring = s->tx;
-    uint32_t i;
-    uint32_t idx;
-    uint8_t *dst;
-
-    if (unlikely(!ring)) {
-        /* Drop. */
-        return size;
-    }
-
-    if (unlikely(size > ring->nr_buf_size)) {
-        RD(5, "[netmap_receive] drop packet of size %d > %d\n",
-                                    (int)size, ring->nr_buf_size);
-        return size;
-    }
-
-    if (nm_ring_empty(ring)) {
-        /* No available slots in the netmap TX ring. */
-        netmap_write_poll(s, true);
-        return 0;
-    }
-
-    i = ring->cur;
-    idx = ring->slot[i].buf_idx;
-    dst = (uint8_t *)NETMAP_BUF(ring, idx);
-
-    ring->slot[i].len = size;
-    ring->slot[i].flags = 0;
-    pkt_copy(buf, dst, size);
-    ring->cur = ring->head = nm_ring_next(ring, i);
-    ioctl(s->nmd->fd, NIOCTXSYNC, NULL);
-
-    return size;
-}
-
 static ssize_t netmap_receive_iov(NetClientState *nc,
                     const struct iovec *iov, int iovcnt)
 {
     NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
     struct netmap_ring *ring = s->tx;
+    unsigned int tail = ring->tail;
+    ssize_t totlen = 0;
     uint32_t last;
     uint32_t idx;
     uint8_t *dst;
     int j;
     uint32_t i;
 
-    if (unlikely(!ring)) {
-        /* Drop the packet. */
-        return iov_size(iov, iovcnt);
-    }
-
-    last = i = ring->cur;
+    last = i = ring->head;
 
     if (nm_ring_space(ring) < iovcnt) {
-        /* Not enough netmap slots. */
+        /* Not enough netmap slots. Tell the kernel that we have seen the new
+         * available slots (so that it notifies us again when it has more
+         * ones), but without publishing any new slots to be processed
+         * (e.g., we don't advance ring->head). */
+        ring->cur = tail;
         netmap_write_poll(s, true);
         return 0;
     }
@@ -222,14 +184,17 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
         int offset = 0;
         int nm_frag_size;
 
+        totlen += iov_frag_size;
+
         /* Split each iovec fragment over more netmap slots, if
            necessary. */
         while (iov_frag_size) {
             nm_frag_size = MIN(iov_frag_size, ring->nr_buf_size);
 
-            if (unlikely(nm_ring_empty(ring))) {
-                /* We run out of netmap slots while splitting the
+            if (unlikely(i == tail)) {
+                /* We ran out of netmap slots while splitting the
                    iovec fragments. */
+                ring->cur = tail;
                 netmap_write_poll(s, true);
                 return 0;
             }
@@ -251,12 +216,24 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
     /* The last slot must not have NS_MOREFRAG set. */
     ring->slot[last].flags &= ~NS_MOREFRAG;
 
-    /* Now update ring->cur and ring->head. */
-    ring->cur = ring->head = i;
+    /* Now update ring->head and ring->cur to publish the new slots and
+     * the new wakeup point. */
+    ring->head = ring->cur = i;
 
     ioctl(s->nmd->fd, NIOCTXSYNC, NULL);
 
-    return iov_size(iov, iovcnt);
+    return totlen;
+}
+
+static ssize_t netmap_receive(NetClientState *nc,
+      const uint8_t *buf, size_t size)
+{
+    struct iovec iov;
+
+    iov.iov_base = (void *)buf;
+    iov.iov_len = size;
+
+    return netmap_receive_iov(nc, &iov, 1);
 }
 
 /* Complete a previous send (backend --> guest) and enable the