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From:   Mao Wenan <maowenan@huawei.com>
To:     <davem@davemloft.net>, <ast@kernel.org>, <daniel@iogearbox.net>,
        <kuba@kernel.org>, <hawk@kernel.org>, <john.fastabend@gmail.com>,
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CC:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <bpf@vger.kernel.org>, <kernel-janitors@vger.kernel.org>
Subject: [PATCH net v2] veth: xdp: use head instead of hard_start
Date:   Tue, 31 Mar 2020 14:06:41 +0800
Message-ID: <20200331060641.79999-1-maowenan@huawei.com>
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xdp.data_hard_start is equal to first address of
struct xdp_frame, which is mentioned in
convert_to_xdp_frame(). But the pointer hard_start
in veth_xdp_rcv_one() is 32 bytes offset of frame,
so it should use head instead of hard_start to
set xdp.data_hard_start. Otherwise, if BPF program
calls helper_function such as bpf_xdp_adjust_head, it
will be confused for xdp_frame_end.

Fixes: 9fc8d518d9d5 ("veth: Handle xdp_frames in xdp napi ring")
Signed-off-by: Mao Wenan <maowenan@huawei.com>
---
 v2: add fixes tag, as well as commit log.
 drivers/net/veth.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index d4cbb9e8c63f..5ea550884bf8 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -506,7 +506,7 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
 		struct xdp_buff xdp;
 		u32 act;
 
-		xdp.data_hard_start = hard_start;
+		xdp.data_hard_start = head;
 		xdp.data = frame->data;
 		xdp.data_end = frame->data + frame->len;
 		xdp.data_meta = frame->data - frame->metasize;
-- 
2.20.1