Re: [PATCH net-next] net: skbuff: use net_zcopy_get() instead of refcount_inc()

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

luyun wrote:
> 
> 在 2026/7/6 21:55, Willem de Bruijn 写道:
> > Yun Lu wrote:
> >> From: Yun Lu <luyun@kylinos.cn>
> >>
> >> The net_zcopy_get() increments the uarg->refcnt, which is called both
> >> in pskb_carve_inside_header() and pskb_carve_inside_nonlinear().
> >> Also use net_zcopy_get() in pskb_expand_head for code consistency.
> >>
> >> No functional change intended.
> >>
> >> Signed-off-by: Yun Lu <luyun@kylinos.cn>
> >> ---
> >>   net/core/skbuff.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> >> index 18dabb4e9cfa..bcf3b2c65fb9 100644
> >> --- a/net/core/skbuff.c
> >> +++ b/net/core/skbuff.c
> >> @@ -2326,7 +2326,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
> >>   		if (skb_orphan_frags(skb, gfp_mask))
> >>   			goto nofrags;
> >>   		if (skb_zcopy(skb))
> >> -			refcount_inc(&skb_uarg(skb)->refcnt);
> >> +			net_zcopy_get(skb_zcopy(skb));
> > This adds some unnecessary instructions in skb_zcopy.
> >
> > It's not terrible and I see the consistency argument. But would make
> > more sense to update the recently added pskb_carve_.. variants instead.
> 
> Thanks for your review.
> 
> The skb_zcopy() does indeed make repeated checks. So following your 
> suggestion,
> 
> I have modified the code as follows:
> 
> -                       net_zcopy_get(skb_zcopy(skb));
> +                       net_zcopy_get(skb_uarg(skb));
> 
> Does it seem more reasonable?
> 
> And I plan to modify all three functions in patch version 2.
> 

That sounds good to me, thanks.