diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 29a2d690d8d5950cf4ff35189ae1e0d31392a7b4..2d21a4793d9d076b46e10338b9785759671b361a 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -879,12 +879,18 @@ static bool mptcp_skb_can_collapse_to(u64 write_seq, !mpext->frozen; } +/* we can append data to the given data frag if: + * - there is space available in the backing page_frag + * - the data frag tail matches the current page_frag free offset + * - the data frag end sequence number matches the current write seq + */ static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, const struct page_frag *pfrag, const struct mptcp_data_frag *df) { return df && pfrag->page == df->page && pfrag->size - pfrag->offset > 0 && + pfrag->offset == (df->offset + df->data_len) && df->data_seq + df->data_len == msk->write_seq; }