From b54c9d5bd6e38edac9ce3a3f95f14a1292b5268d Mon Sep 17 00:00:00 2001 From: Jonathan Lemon Date: Tue, 30 Jul 2019 07:40:33 -0700 Subject: net: Use skb_frag_off accessors Use accessor functions for skb fragment's page_offset instead of direct references, in preparation for bvec conversion. Signed-off-by: Jonathan Lemon Signed-off-by: David S. Miller --- drivers/net/xen-netfront.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/net/xen-netfront.c') diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 8d33970a2950..b930d5f95222 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -531,7 +531,7 @@ static int xennet_count_skb_slots(struct sk_buff *skb) for (i = 0; i < frags; i++) { skb_frag_t *frag = skb_shinfo(skb)->frags + i; unsigned long size = skb_frag_size(frag); - unsigned long offset = frag->page_offset; + unsigned long offset = skb_frag_off(frag); /* Skip unused frames from start of page */ offset &= ~PAGE_MASK; @@ -674,8 +674,8 @@ static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev /* Requests for all the frags. */ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; - tx = xennet_make_txreqs(queue, tx, skb, - skb_frag_page(frag), frag->page_offset, + tx = xennet_make_txreqs(queue, tx, skb, skb_frag_page(frag), + skb_frag_off(frag), skb_frag_size(frag)); } @@ -1040,7 +1040,7 @@ err: if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD) NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD; - skb_shinfo(skb)->frags[0].page_offset = rx->offset; + skb_frag_off_set(&skb_shinfo(skb)->frags[0], rx->offset); skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status); skb->data_len = rx->status; skb->len += rx->status; -- cgit From 00b368502d18f790ab715e055869fd4bb7484a9b Mon Sep 17 00:00:00 2001 From: Dongli Zhang Date: Mon, 16 Sep 2019 11:46:59 +0800 Subject: xen-netfront: do not assume sk_buff_head list is empty in error handling When skb_shinfo(skb) is not able to cache extra fragment (that is, skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS), xennet_fill_frags() assumes the sk_buff_head list is already empty. As a result, cons is increased only by 1 and returns to error handling path in xennet_poll(). However, if the sk_buff_head list is not empty, queue->rx.rsp_cons may be set incorrectly. That is, queue->rx.rsp_cons would point to the rx ring buffer entries whose queue->rx_skbs[i] and queue->grant_rx_ref[i] are already cleared to NULL. This leads to NULL pointer access in the next iteration to process rx ring buffer entries. Below is how xennet_poll() does error handling. All remaining entries in tmpq are accounted to queue->rx.rsp_cons without assuming how many outstanding skbs are remained in the list. 985 static int xennet_poll(struct napi_struct *napi, int budget) ... ... 1032 if (unlikely(xennet_set_skb_gso(skb, gso))) { 1033 __skb_queue_head(&tmpq, skb); 1034 queue->rx.rsp_cons += skb_queue_len(&tmpq); 1035 goto err; 1036 } It is better to always have the error handling in the same way. Fixes: ad4f15dc2c70 ("xen/netfront: don't bug in case of too many frags") Signed-off-by: Dongli Zhang Signed-off-by: David S. Miller --- drivers/net/xen-netfront.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/xen-netfront.c') diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 8d33970a2950..5f5722bf6762 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -906,7 +906,7 @@ static RING_IDX xennet_fill_frags(struct netfront_queue *queue, __pskb_pull_tail(skb, pull_to - skb_headlen(skb)); } if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) { - queue->rx.rsp_cons = ++cons; + queue->rx.rsp_cons = ++cons + skb_queue_len(list); kfree_skb(nskb); return ~0U; } -- cgit