diff options
| -rw-r--r-- | net/netmap.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/net/netmap.c b/net/netmap.c index 852106af29..0cc8f545c5 100644 --- a/net/netmap.c +++ b/net/netmap.c @@ -159,21 +159,22 @@ static ssize_t netmap_receive_iov(NetClientState *nc, { 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; } @@ -183,14 +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; } @@ -212,12 +216,13 @@ 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, |