diff options
| -rw-r--r-- | drivers/net/xen-netback/netback.c | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 438d0c09b7e6..cd0bd95ccc14 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -192,8 +192,8 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head) * into multiple copies tend to give large frags their * own buffers as before. */ - if ((offset + size > MAX_BUFFER_OFFSET) && - (size <= MAX_BUFFER_OFFSET) && offset && !head) + BUG_ON(size > MAX_BUFFER_OFFSET); + if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head) return true; return false; @@ -482,6 +482,8 @@ static void xenvif_rx_action(struct xenvif *vif) while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) { RING_IDX max_slots_needed; + RING_IDX old_req_cons; + RING_IDX ring_slots_used; int i; /* We need a cheap worse case estimate for the number of @@ -493,9 +495,28 @@ static void xenvif_rx_action(struct xenvif *vif) PAGE_SIZE); for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { unsigned int size; + unsigned int offset; + size = skb_frag_size(&skb_shinfo(skb)->frags[i]); - max_slots_needed += DIV_ROUND_UP(size, PAGE_SIZE); + offset = skb_shinfo(skb)->frags[i].page_offset; + + /* For a worse-case estimate we need to factor in + * the fragment page offset as this will affect the + * number of times xenvif_gop_frag_copy() will + * call start_new_rx_buffer(). + */ + max_slots_needed += DIV_ROUND_UP(offset + size, + PAGE_SIZE); } + + /* To avoid the estimate becoming too pessimal for some + * frontends that limit posted rx requests, cap the estimate + * at MAX_SKB_FRAGS. + */ + if (max_slots_needed > MAX_SKB_FRAGS) + max_slots_needed = MAX_SKB_FRAGS; + + /* We may need one more slot for GSO metadata */ if (skb_is_gso(skb) && (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 || skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)) @@ -511,8 +532,12 @@ static void xenvif_rx_action(struct xenvif *vif) vif->rx_last_skb_slots = 0; sco = (struct skb_cb_overlay *)skb->cb; + + old_req_cons = vif->rx.req_cons; sco->meta_slots_used = xenvif_gop_skb(skb, &npo); - BUG_ON(sco->meta_slots_used > max_slots_needed); + ring_slots_used = vif->rx.req_cons - old_req_cons; + + BUG_ON(ring_slots_used > max_slots_needed); __skb_queue_tail(&rxq, skb); } |