From: Jakub Kicinski <kuba@xxxxxxxxxx>
Date: Fri, 15 Nov 2024 18:40:59 -0800
> 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?
Correct. I realized that when replying to Ido =\
>
>> + 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;
>> +}
Thanks,
Olek
