On 2024/1/9 9:14, Mina Almasry wrote:

...

 
+		if (WARN_ON_ONCE(!skb_frag_page(&skb_shinfo(skb)->frags[0]))) {

I am really hate to bring it up again.
If you are not willing to introduce a new helper, do you care to use some
existing API like skb_frag_address_safe()?

+			ret = -EINVAL;
+			goto out;
+		}
+
 		iov_iter_bvec(&msg.msg_iter, ITER_SOURCE,
-			      skb_shinfo(skb)->frags, skb_shinfo(skb)->nr_frags,
-			      msize);
+			      (const struct bio_vec *)skb_shinfo(skb)->frags,
+			      skb_shinfo(skb)->nr_frags, msize);

I think we need to use some built-time checking to ensure some consistency
between skb_frag_t and bio_vec.

 		iov_iter_advance(&msg.msg_iter, txm->frag_offset);
 
 		do {