From 8687b329482fe2191f9a5534f1172749c1e9d8b1 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Fri, 15 Jan 2016 14:55:34 +0000 Subject: [PATCH] xen-netback: use skb to determine number of required guest Rx requests Using the MTU or GSO size to determine the number of required guest Rx requests for an skb was subtly broken since these value may change at runtime. After c026203f6c068840ccb9b85842c218b1261db2ad (xen-netback: always fully coalesce guest Rx packets) we always fully pack a packet into its guest Rx slots. Calculating the number of required slots from the packet length is then easy. Signed-off-by: David Vrabel Signed-off-by: David S. Miller --- drivers/net/xen-netback/netback.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 1049c34e7d430..61b97c34bb3b8 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -149,20 +149,19 @@ static inline pending_ring_idx_t pending_index(unsigned i) return i & (MAX_PENDING_REQS-1); } -static int xenvif_rx_ring_slots_needed(struct xenvif *vif) -{ - if (vif->gso_mask) - return DIV_ROUND_UP(vif->dev->gso_max_size, XEN_PAGE_SIZE) + 1; - else - return DIV_ROUND_UP(vif->dev->mtu, XEN_PAGE_SIZE); -} - static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue) { RING_IDX prod, cons; + struct sk_buff *skb; int needed; - needed = xenvif_rx_ring_slots_needed(queue->vif); + skb = skb_peek(&queue->rx_queue); + if (!skb) + return false; + + needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE); + if (skb_is_gso(skb)) + needed++; do { prod = queue->rx.sring->req_prod; @@ -2005,8 +2004,7 @@ static bool xenvif_rx_queue_ready(struct xenvif_queue *queue) static bool xenvif_have_rx_work(struct xenvif_queue *queue) { - return (!skb_queue_empty(&queue->rx_queue) - && xenvif_rx_ring_slots_available(queue)) + return xenvif_rx_ring_slots_available(queue) || (queue->vif->stall_timeout && (xenvif_rx_queue_stalled(queue) || xenvif_rx_queue_ready(queue))) -- 2.39.5