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 180B81FB4F for ; Tue, 1 Aug 2023 09:44:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90E97C433C7; Tue, 1 Aug 2023 09:44:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690883087; bh=ZAQJNBRmR9hUfwPoOvGTWhSg3c6HH8N+XCyaDxhkRjU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FcNgLAdij1tuHO0Bhkdx4Be44bLB0kx7qbiAIKhhaH0ERpKSTWfLte9ecn2vRB5O1 9yH9RSamFOQABIlyAvg7unU3M0b7ceDkty61x12y8HmP8dPJ55VBJ0POMkfVRGrsbb pa6vIPSBvC+vGGOhUEJIS5LlMWWwugMCmC/NkOVA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wei Fang , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.4 093/239] net: fec: tx processing does not call XDP APIs if budget is 0 Date: Tue, 1 Aug 2023 11:19:17 +0200 Message-ID: <20230801091929.094603277@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230801091925.659598007@linuxfoundation.org> References: <20230801091925.659598007@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Wei Fang [ Upstream commit 15cec633fc7bfe4cd69aa012c3b35b31acfc86f2 ] According to the clarification [1] in the latest napi.rst, the tx processing cannot call any XDP (or page pool) APIs if the "budget" is 0. Because NAPI is called with the budget of 0 (such as netpoll) indicates we may be in an IRQ context, however, we cannot use the page pool from IRQ context. [1] https://lore.kernel.org/all/20230720161323.2025379-1-kuba@kernel.org/ Fixes: 20f797399035 ("net: fec: recycle pages for transmitted XDP frames") Signed-off-by: Wei Fang Suggested-by: Jakub Kicinski Link: https://lore.kernel.org/r/20230725074148.2936402-1-wei.fang@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/freescale/fec_main.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index a1b0abe54a0e5..92410f30ad241 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1372,7 +1372,7 @@ fec_enet_hwtstamp(struct fec_enet_private *fep, unsigned ts, } static void -fec_enet_tx_queue(struct net_device *ndev, u16 queue_id) +fec_enet_tx_queue(struct net_device *ndev, u16 queue_id, int budget) { struct fec_enet_private *fep; struct xdp_frame *xdpf; @@ -1416,6 +1416,14 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id) if (!skb) goto tx_buf_done; } else { + /* Tx processing cannot call any XDP (or page pool) APIs if + * the "budget" is 0. Because NAPI is called with budget of + * 0 (such as netpoll) indicates we may be in an IRQ context, + * however, we can't use the page pool from IRQ context. + */ + if (unlikely(!budget)) + break; + xdpf = txq->tx_buf[index].xdp; if (bdp->cbd_bufaddr) dma_unmap_single(&fep->pdev->dev, @@ -1508,14 +1516,14 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id) writel(0, txq->bd.reg_desc_active); } -static void fec_enet_tx(struct net_device *ndev) +static void fec_enet_tx(struct net_device *ndev, int budget) { struct fec_enet_private *fep = netdev_priv(ndev); int i; /* Make sure that AVB queues are processed first. */ for (i = fep->num_tx_queues - 1; i >= 0; i--) - fec_enet_tx_queue(ndev, i); + fec_enet_tx_queue(ndev, i, budget); } static void fec_enet_update_cbd(struct fec_enet_priv_rx_q *rxq, @@ -1858,7 +1866,7 @@ static int fec_enet_rx_napi(struct napi_struct *napi, int budget) do { done += fec_enet_rx(ndev, budget - done); - fec_enet_tx(ndev); + fec_enet_tx(ndev, budget); } while ((done < budget) && fec_enet_collect_events(fep)); if (done < budget) { -- 2.39.2