From db43a282d3ec92ea45109c5551fff3dcc5afef02 Mon Sep 17 00:00:00 2001 From: Octavian Purdila Date: Fri, 27 Jun 2008 17:27:21 -0700 Subject: [PATCH] tcp: fix for splice receive when used with software LRO If an skb has nr_frags set to zero but its frag_list is not empty (as it can happen if software LRO is enabled), and a previous tcp_read_sock has consumed the linear part of the skb, then __skb_splice_bits: (a) incorrectly reports an error and (b) forgets to update the offset to account for the linear part Any of the two problems will cause the subsequent __skb_splice_bits call (the one that handles the frag_list skbs) to either skip data, or, if the unadjusted offset is greater then the size of the next skb in the frag_list, make tcp_splice_read loop forever. Signed-off-by: Octavian Purdila Signed-off-by: David S. Miller --- net/core/skbuff.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 1e556d31211..366621610e7 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1292,12 +1292,14 @@ static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset, { unsigned int nr_pages = spd->nr_pages; unsigned int poff, plen, len, toff, tlen; - int headlen, seg; + int headlen, seg, error = 0; toff = *offset; tlen = *total_len; - if (!tlen) + if (!tlen) { + error = 1; goto err; + } /* * if the offset is greater than the linear part, go directly to @@ -1339,7 +1341,8 @@ static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset, * just jump directly to update and return, no point * in going over fragments when the output is full. */ - if (spd_fill_page(spd, virt_to_page(p), plen, poff, skb)) + error = spd_fill_page(spd, virt_to_page(p), plen, poff, skb); + if (error) goto done; tlen -= plen; @@ -1369,7 +1372,8 @@ map_frag: if (!plen) break; - if (spd_fill_page(spd, f->page, plen, poff, skb)) + error = spd_fill_page(spd, f->page, plen, poff, skb); + if (error) break; tlen -= plen; @@ -1382,7 +1386,10 @@ done: return 0; } err: - return 1; + /* update the offset to reflect the linear part skip, if any */ + if (!error) + *offset = toff; + return error; } /* -- 2.41.1