Re: [PATCH net-next v5 2/3] net: mirror skb frag ref/unref helpers

[Jacob Keller]

On 4/8/2024 8:29 AM, Mina Almasry wrote:
> Refactor some of the skb frag ref/unref helpers for improved clarity.
> 
> Implement napi_pp_get_page() to be the mirror counterpart of
> napi_pp_put_page().
> 
> Implement skb_page_ref() to be the mirror of skb_page_unref().
> 
> Improve __skb_frag_ref() to become a mirror counterpart of
> __skb_frag_unref(). Previously unref could handle pp & non-pp pages,
> while the ref could only handle non-pp pages. Now both the ref & unref
> helpers can correctly handle both pp & non-pp pages.
> 
> Now that __skb_frag_ref() can handle both pp & non-pp pages, remove
> skb_pp_frag_ref(), and use __skb_frag_ref() instead.  This lets us
> remove pp specific handling from skb_try_coalesce.
> 
> Additionally, since __skb_frag_ref() can now handle both pp & non-pp
> pages, a latent issue in skb_shift() should now be fixed. Previously
> this function would do a non-pp ref & pp unref on potential pp frags
> (fragfrom). After this patch, skb_shift() should correctly do a pp
> ref/unref on pp frags.
> 

The description sounds like a lot is going on here, and at first I was
thinking this should be split further. However I think that would just
end up with a lot of needless thrash.

Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>