[PATCH net-next v2 1/2] xsk: respect the offsets when copying frags

[Bui Quang Minh <minhquangbui99@gmail.com>]

In commit 560d958c6c68 ("xsk: add generic XSk &xdp_buff -> skb
conversion"), we introduce a helper to convert zerocopy xdp_buff to skb.
However, in the frag copy, we mistakenly ignore the frag's offset. This
commit adds the missing offset when copying frags in
xdp_copy_frags_from_zc(). This function is not used anywhere so no
backport is needed.

Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
---
 net/core/xdp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index ea819764ae39..89111c68e545 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -698,7 +698,8 @@ static noinline bool xdp_copy_frags_from_zc(struct sk_buff *skb,
 	nr_frags = xinfo->nr_frags;
 
 	for (u32 i = 0; i < nr_frags; i++) {
-		u32 len = skb_frag_size(&xinfo->frags[i]);
+		const skb_frag_t *frag = &xinfo->frags[i];
+		u32 len = skb_frag_size(frag);
 		u32 offset, truesize = len;
 		netmem_ref netmem;
 
@@ -708,8 +709,8 @@ static noinline bool xdp_copy_frags_from_zc(struct sk_buff *skb,
 			return false;
 		}
 
-		memcpy(__netmem_address(netmem),
-		       __netmem_address(xinfo->frags[i].netmem),
+		memcpy(__netmem_address(netmem) + offset,
+		       __netmem_address(frag->netmem) + skb_frag_off(frag),
 		       LARGEST_ALIGN(len));
 		__skb_fill_netmem_desc_noacc(sinfo, i, netmem, offset, len);
 
-- 
2.43.0