From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794449623; b=B78SdDfyaUUtiVkYooiJIZts0F5n8Y6oD/+EjynriA0YPAWIjt94n7WrX4x9MWcrkvOs SI+7DYRxylMDzMhh7zAaw+UyapK/GxygAsqzoWVDQiPjF69WsrrKqFAo9a3MTo2XAZu5u /dWadruNQtDkmsdM4i2CwgiUO7E2fR7gsOVpzn3VwKd4nOs/8dcBjNbaVd/3n+mvFz9uw Ej3LxIdqRviLRaT7oAL+o9UgAHgJ1TkhieXwjQ3Ku3aLJFnusb45pgirhBiwV7FMOEOkh kCWBJth3YQhAhvDgVDX2q1TmJ/7rPecLfZ2/v6pJbslr/UoOiVYpdZUikOmByjI4ycg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794449623; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=ASxibD7eZkzQFD1xdlQZW+ZvbrwHxv8p5UBEzGgjh6c=; b=UwTXVFHiWCyoFLppQUb2HQOMyDfcJqlBRonMxUA49YObskqTv242Vi2kgoMN5lzpJZjI NMnMpbCbw/ScH7kQp1cirI9HvOQK3zpP5NIdYSbnuNy9gfmmL95wyrrHnKYlgp6TSvemy /+eDfQm+6rR3MzWBuQtkQ8GYnm7cjgpTbK71WvO9gTQl7M/W7WSq82eV+XHraTX92IA0+ QPG3oe6isRzL9fIJuln5h45ZzR7qk5iRvUY+vmbVnP3QxPqINM9F6eYqSPha1aaOzxbEk FhKL7e3sOGoFPshxjOlkCflzbd4ybW8RILsmGJBtLLEv9cxSCd0RgPkce4xneUlrfGw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="aW3ZCB/I"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E9040606A327; Thu, 12 Nov 2026 02:13:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=aW3ZCB/I Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BF0B1F00A05; Thu, 12 Nov 2026 02:13:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794449622; bh=ASxibD7eZkzQFD1xdlQZW+ZvbrwHxv8p5UBEzGgjh6c=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=aW3ZCB/I5FqCT1QTrrYSfnW73l065oZNdZXhjvby7kHi1ZSkeVXLP3eqLlENLiHaP iQnDSIrUQGyoKlO8Q1pv1kn0/pXGMJ0rgxkR9C+PI58GyHZBSvltR5SSAq9Qj5wdGQ IgstssvDXsHNClcHzQTRvOI1pRqhUXqk9Ax9x/rHdZKWnuQYE50XfnKo20q5FqEUsu RczCKoIqSWrmUv3KT65booOJnRKsVUN0XxVKa883AIUYHHRiEhye6H1ZVgId2lvGAa jUaSporZwXBFSDy7qmpiNiMmXb8ql0dG6NcRcowuF3jut3t6FBSiYVBMtbhR/MH0ip HGNU6c8gjHwLw== Date: Wed, 11 Nov 2026 18:13:41 -0800 From: Jakub Kicinski To: Lorenzo Bianconi Cc: Maxime Chevallier , Andrew Lunn , "David S. Miller" , Eric Dumazet , Paolo Abeni , Maxime Coquelin , Alexandre Torgue , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , Jose Abreu , Ong Boon Leong , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, bpf@vger.kernel.org, Nicolai Buchwitz Subject: Re: [PATCH net-next v9] net: stmmac: rework stmmac_rx to support XDP rx multi-buff Message-ID: <20261111181341.56706354@kernel.org> In-Reply-To: <20261106-stmmac-rx-mb-v9-1-c099c923664b@oss.qualcomm.com> References: <20261106-stmmac-rx-mb-v9-1-c099c923664b@oss.qualcomm.com> X-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 06 Nov 2026 11:54:19 +0100 Lorenzo Bianconi wrote: > +static struct sk_buff *stmmac_build_skb(struct xdp_buff *xdp) > +{ > + struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); > + u32 metasize = xdp->data - xdp->data_meta; > + struct sk_buff *skb; > + u8 num_frags = 0; > + > + if (unlikely(xdp_buff_has_frags(xdp))) > + num_frags = sinfo->nr_frags; > + > + skb = napi_build_skb(xdp->data_hard_start, xdp->frame_sz); > + if (!skb) > + return NULL; > + > + skb_mark_for_recycle(skb); > + skb_reserve(skb, xdp->data - xdp->data_hard_start); > + skb_put(skb, xdp->data_end - xdp->data); > + if (metasize) > + skb_metadata_set(skb, metasize); > + > + if (unlikely(xdp_buff_has_frags(xdp))) > + xdp_update_skb_frags_info(skb, num_frags, sinfo->xdp_frags_size, > + sinfo->xdp_frags_truesize, > + xdp_buff_get_skb_flags(xdp)); > + return skb; > +} This is almost identical to xdp_build_skb_from_buff(), why not use the common code? > +static void > +stmmac_xdp_put_buff(struct stmmac_rx_queue *rx_q, struct xdp_buff *xdp, > + bool allow_direct) > +{ > + struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); > + int i; > + > + if (likely(!xdp_buff_has_frags(xdp))) > + goto out; > + > + for (i = 0; i < sinfo->nr_frags; i++) > + page_pool_put_full_page(rx_q->page_pool, > + skb_frag_page(&sinfo->frags[i]), > + allow_direct); > +out: > + page_pool_put_full_page(rx_q->page_pool, virt_to_head_page(xdp->data), > + allow_direct); > +} > + > +static int stmmac_xdp_shrink_tail(struct stmmac_rx_queue *rx_q, > + struct xdp_buff *xdp, int offset) > +{ > + struct skb_shared_info *sinfo; > + int i; > + > + if (unlikely(offset < 0 || > + offset > (int)xdp_get_buff_len(xdp) - ETH_HLEN)) > + return -EINVAL; > + > + if (likely(!xdp_buff_has_frags(xdp))) { > + xdp->data_end -= offset; > + return 0; > + } > + > + sinfo = xdp_get_shared_info_from_buff(xdp); > + for (i = sinfo->nr_frags - 1; i >= 0 && offset > 0; i--) { > + skb_frag_t *frag = &sinfo->frags[i]; > + int delta = min_t(int, offset, skb_frag_size(frag)); > + > + if (delta == skb_frag_size(frag)) { > + /* The whole frag is consumed by the strip: return it > + * to the page pool right away. Its ring slot still > + * carries the page DMA address until stmmac_rx_refill() > + * re-arms it at the end of the NAPI poll. This is > + * safe because HW cannot touch the slot until then. > + */ > + page_pool_put_full_page(rx_q->page_pool, > + skb_frag_page(frag), true); > + sinfo->nr_frags--; > + sinfo->xdp_frags_truesize -= xdp->frame_sz; > + } else { > + skb_frag_size_sub(frag, delta); > + } > + > + sinfo->xdp_frags_size -= delta; > + offset -= delta; > + } > + > + if (unlikely(!sinfo->nr_frags)) { > + xdp_buff_clear_frags_flag(xdp); > + xdp_buff_clear_frag_pfmemalloc(xdp); > + xdp->data_end -= offset; > + } > + > + return 0; > +} These two OTOH could easily become new common helpers, they seem to do nothing stmmac specific?