From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0D8902D5950; Wed, 25 Mar 2026 04:03:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774411424; cv=none; b=G0HMPnKeZinZukv96VcF3rjZvs4i68gL36/T7oyokPZWPxsi4exKDq4Djkb1mEW4uo8cpzIpH/i7J/BSw4hj7JfKjmSTg9Pa3AqgqRUyRXer460rkea3qBcOGM0HMmUmjufxEhtaVN8PwubS60mS9nqEY9MwqSbOLk9WVGkzygw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774411424; c=relaxed/simple; bh=rKjBFwTl8y/aFDsfkycqbaBWF5p3amFnYH+OOdOGJH4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=uiRg3dT1fs58Tzd2Pwpsqwyqv4tQ/f4t6uZ6pxfo+d1d7tN2tbZjOhABp/wOmS8BmjmUsef0+7JR5n7/a8kmoQqb5S+jebQ9ksAhHFZWYoCXcEqTUtx5MylWGbnCHpjabmX2Xzt+Lojek/2Z7Dk4gflwuFmBQLKcrqybaQUQMDo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eCXTVWx/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eCXTVWx/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2B43C4CEF7; Wed, 25 Mar 2026 04:03:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774411423; bh=rKjBFwTl8y/aFDsfkycqbaBWF5p3amFnYH+OOdOGJH4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=eCXTVWx/J7qoyx8JMFP/pZWjXDY3JfisKDEUp5PmU0+XnzZ07ItWe+obtPr53BSBR 7ArpBufimHSENmQQLd8Vpb99+nzF5ECvpzOmJQmcq/S6YvmYpzFH7YtAvGm6ndcEia hz8us2dfMdY6LwGxdMOOceS63yzNDmjh6gWsiUdmvcInpQXRInAM6teuwgH4mNGSsn +qBodKTQ+6tfmnmfAFu+yrMbdYH/Atm8YCjrgbzVKdNGSM9fnJuPxzZHeU24dnydou wK/pfopTAu8+BboMoriYTF9zO0c1vuuFbA1uY37UNBHs62QC6ZrCVsU5QsylSgkTzz NRf4n/HUM9S9Q== Date: Tue, 24 Mar 2026 21:03:42 -0700 From: Jakub Kicinski To: Nicolai Buchwitz Cc: netdev@vger.kernel.org, Justin Chen , Simon Horman , Doug Berger , Florian Fainelli , Broadcom internal kernel review list , Andrew Lunn , "David S. Miller" , Eric Dumazet , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , linux-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [PATCH net-next v4 4/6] net: bcmgenet: add XDP_TX support Message-ID: <20260324210342.61b0b5f8@kernel.org> In-Reply-To: <20260323120539.136029-5-nb@tipi-net.de> References: <20260323120539.136029-1-nb@tipi-net.de> <20260323120539.136029-5-nb@tipi-net.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 23 Mar 2026 13:05:33 +0100 Nicolai Buchwitz wrote: > Implement XDP_TX using ring 16 (DESC_INDEX), the hardware default > descriptor ring, dedicated to XDP TX for isolation from SKB TX queues. > > Ring 16 gets 32 BDs carved from ring 0's allocation. TX completion is > piggybacked on RX NAPI poll since ring 16's INTRL2_1 bit collides with > RX ring 0, similar to how bnxt, ice, and other XDP drivers handle TX > completion within the RX poll path. > > The GENET MAC has TBUF_64B_EN set globally, requiring every TX buffer > to start with a 64-byte struct status_64 (TSB). For local XDP_TX, the > TSB is prepended by backing xdp->data into the RSB area (unused after > BPF execution) and zeroing it. For foreign frames redirected from other > devices, the TSB is written into the xdp_frame headroom. > > The page_pool DMA direction is changed from DMA_FROM_DEVICE to > DMA_BIDIRECTIONAL to allow TX reuse of the existing DMA mapping. drivers/net/ethernet/broadcom/genet/bcmgenet.c:2420:27: warning: variable 'tx_ring' set but not used [-Wunused-but-set-variable] 2420 | struct bcmgenet_tx_ring *tx_ring; | ^ -- pw-bot: cr