On Wed, 13 Nov 2024 16:24:34 +0100 Alexander Lobakin wrote:
> +static inline bool __xdp_buff_add_frag(struct xdp_buff *xdp, struct page *page,
> + u32 offset, u32 size, u32 truesize,
> + bool try_coalesce)
> +{
> + struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
> + skb_frag_t *prev;
> + u32 nr_frags;
> +
> + if (!xdp_buff_has_frags(xdp)) {
> + xdp_buff_set_frags_flag(xdp);
> +
> + nr_frags = 0;
> + sinfo->xdp_frags_size = 0;
> + sinfo->xdp_frags_truesize = 0;
> +
> + goto fill;
> + }
> +
> + nr_frags = sinfo->nr_frags;
> + if (unlikely(nr_frags == MAX_SKB_FRAGS))
> + return false;
> +
> + prev = &sinfo->frags[nr_frags - 1];
> + if (try_coalesce && page == skb_frag_page(prev) &&
> + offset == skb_frag_off(prev) + skb_frag_size(prev))
> + skb_frag_size_add(prev, size);
don't we have to release the reference if we coalesced?
> + else
> +fill:
> + __skb_fill_page_desc_noacc(sinfo, nr_frags++, page,
> + offset, size);
> +
> + sinfo->nr_frags = nr_frags;
> + sinfo->xdp_frags_size += size;
> + sinfo->xdp_frags_truesize += truesize;
> +
> + return true;
> +}
