Re: [RFC PATCH net-next v1 4/4] net: page_pool: use netmem_t instead of struct page in API

On 2024/1/3 0:14, Mina Almasry wrote:

The idea being that skb_frag_page() can return NULL if the frag is not
paged, and the relevant callers are modified to handle that.

There are many existing drivers which are not expecting NULL returning for
skb_frag_page() as those drivers are not supporting devmem, adding additionl
checking overhead in skb_frag_page() for those drivers does not make much
sense, IMHO, it may make more sense to introduce a new helper for the driver
supporting devmem or networking core that needing dealing with both normal
page and devmem.

And we are also able to keep the old non-NULL returning semantic for
skb_frag_page().