From fc02e8cb0300c0146e1d4668a75663eb225d8182 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sat, 9 Oct 2021 10:52:50 -0400 Subject: [PATCH] virtio_net: clarify tailroom logic MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Make tailroom math follow same logic as everything else, subtracing values in the order in which things are laid out in the buffer. Tested-by: Corentin Noël Signed-off-by: Michael S. Tsirkin --- drivers/net/virtio_net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 4ad25a8..6d8c874 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -406,12 +406,13 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, * add_recvbuf_mergeable() + get_mergeable_buf_len() */ truesize = headroom ? PAGE_SIZE : truesize; - tailroom = truesize - len - headroom - (hdr_padded_len - hdr_len); + tailroom = truesize - headroom; buf = p - headroom; len -= hdr_len; offset += hdr_padded_len; p += hdr_padded_len; + tailroom -= hdr_padded_len + len; shinfo_size = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); -- 2.7.4