From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9CF7C4332F for ; Thu, 17 Nov 2022 12:18:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239877AbiKQMSQ (ORCPT ); Thu, 17 Nov 2022 07:18:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240083AbiKQMSK (ORCPT ); Thu, 17 Nov 2022 07:18:10 -0500 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.153.233]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D40970A38 for ; Thu, 17 Nov 2022 04:17:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1668687478; x=1700223478; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=ydEj2Q+uMDTwX7o4flBR4EgodQ5AcTUWYlaTInRQA1k=; b=d82qAvJoen/IJOElKJ0rX82Asf0l9LJOBsOZBwRC6puYBkx9fPnp0exz L+1kY/Q4gD2+8HIT3sIdWij+DbKXf+R1f8QSaBsicz0KnYw/lDaleqsdh UffbnZJs1gdxelu9mHEUFLXD7eXGmcFBXeok5WqpjJZobZZErInXbdlfS 8zt1guFlV1y2W1TEIAe/JkAji21vDVCBrhMknfxyuCoENzrH8jwzDyeEM f+cTieDByB8GxcrhYuOyfVNIBhwH0UmBImJwA0sMulzt2jN8JtP5bZrBP XXhBdvjvG3rLkwH6ZX3uqr321hE7fVicJOT+PRExeSTGOjp6UgF9CvJKK g==; X-IronPort-AV: E=Sophos;i="5.96,171,1665471600"; d="scan'208";a="189362903" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa5.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 17 Nov 2022 05:17:57 -0700 Received: from chn-vm-ex02.mchp-main.com (10.10.85.144) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Thu, 17 Nov 2022 05:17:55 -0700 Received: from localhost (10.10.115.15) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server id 15.1.2507.12 via Frontend Transport; Thu, 17 Nov 2022 05:17:55 -0700 Date: Thu, 17 Nov 2022 13:22:44 +0100 From: Horatiu Vultur To: Casper Andersson CC: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Lars Povlsen , "Steen Hegelund" , Daniel Machon , , "Richard Cochran" , Subject: Re: [PATCH net] net: microchip: sparx5: correctly free skb in xmit Message-ID: <20221117122244.3ag5bonu3w7xwu4v@soft-dev3-1> References: <20221116095740.176286-1-casper.casan@gmail.com> <20221116114115.eojkihqplenjv6l3@soft-dev3-1> <20221116123435.5o76prb33mpte5hf@wse-c0155> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <20221116123435.5o76prb33mpte5hf@wse-c0155> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The 11/16/2022 13:34, Casper Andersson wrote: > > Hi Horatiu, > > On 2022-11-16 12:41, Horatiu Vultur wrote: > > The 11/16/2022 10:57, Casper Andersson wrote: > > > > Hi Casper, > > > > > > > > consume_skb on transmitted, kfree_skb on dropped, do not free on TX_BUSY. > > > > > > Previously the xmit function could return -EBUSY without freeing, which > > > supposedly is interpreted as a drop. And was using kfree on successfully > > > transmitted packets. > > > https://lore.kernel.org/netdev/20220920072948.33c25dd2@kernel.org/t/#mdb821eb507a207dd5e27683239ffa7ec7199421a > > > > > > Fixes: 10615907e9b5 ("net: sparx5: switchdev: adding frame DMA functionality") > > > > Actually the fix shouldn't be: > > 70dfe25cd866 ("net: sparx5: Update extraction/injection for timestamping") ? > > Because this commit introduced the function sparx5_ptp_txtstamp_request, > > and it didn't free the skb on error path. > > > > As I understood Jakub's comment (linked above) part of the issue was > that sparx5_inject (and sparx5_ptp_txtstamp_request) returns -EBUSY > instead of NETDEV_TX_BUSY (which then gets returned further). So maybe > it should be separate patches for the two cases. Ah.. I think now I understand it. It is up to you how to take this. > > While on the topic, I noticed another possible issue with > sparx5_fdma_xmit where it increments dropped, but keeps going with > transmit. I assume it should return and indicate dropped here. > > if (!(db_hw->status & FDMA_DCB_STATUS_DONE)) > tx->dropped++; > db = list_first_entry(&tx->db_list, struct sparx5_db, list); You are correct, that looks wrong also to me. It should return and drop the frame. > ... > > > > Signed-off-by: Casper Andersson > > > --- > > > I am not entirely sure about the following construct which is present in > > > both sparx5 and lan966x drivers and returns before consuming the skb. Is > > > there any reason it does not free the skb? > > > > Yes, this case will happen when the HW is configured to timestamp frames > > and return the timestamp back to the SW. And in that case the frame is freed > > once the timestamp is received. Have a look in the function > > 'sparx5_ptp_irq_handler' > > Alright, that makes sense. > > > > > > > > > if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP && > > > SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP) > > > return NETDEV_TX_OK; > > > > > > > > > > > > > > > .../ethernet/microchip/sparx5/sparx5_fdma.c | 2 +- > > > .../ethernet/microchip/sparx5/sparx5_main.h | 2 +- > > > .../ethernet/microchip/sparx5/sparx5_packet.c | 47 ++++++++++--------- > > > 3 files changed, 27 insertions(+), 24 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c b/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c > > > index 66360c8c5a38..302e7ff55585 100644 > > > --- a/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c > > > +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c > > > @@ -306,7 +306,7 @@ static struct sparx5_tx_dcb_hw *sparx5_fdma_next_dcb(struct sparx5_tx *tx, > > > return next_dcb; > > > } > > > > > > -int sparx5_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb) > > > +netdev_tx_t sparx5_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb) > > > { > > > struct sparx5_tx_dcb_hw *next_dcb_hw; > > > struct sparx5_tx *tx = &sparx5->tx; > > > diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_main.h b/drivers/net/ethernet/microchip/sparx5/sparx5_main.h > > > index 7a83222caa73..34b8d11f76df 100644 > > > --- a/drivers/net/ethernet/microchip/sparx5/sparx5_main.h > > > +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_main.h > > > @@ -312,7 +312,7 @@ void sparx5_port_inj_timer_setup(struct sparx5_port *port); > > > /* sparx5_fdma.c */ > > > int sparx5_fdma_start(struct sparx5 *sparx5); > > > int sparx5_fdma_stop(struct sparx5 *sparx5); > > > -int sparx5_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb); > > > +netdev_tx_t sparx5_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb); > > > irqreturn_t sparx5_fdma_handler(int irq, void *args); > > > > > > /* sparx5_mactable.c */ > > > diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c > > > index 83c16ca5b30f..6fc1c1e410f6 100644 > > > --- a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c > > > +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c > > > @@ -159,10 +159,10 @@ static void sparx5_xtr_grp(struct sparx5 *sparx5, u8 grp, bool byte_swap) > > > netif_rx(skb); > > > } > > > > > > -static int sparx5_inject(struct sparx5 *sparx5, > > > - u32 *ifh, > > > - struct sk_buff *skb, > > > - struct net_device *ndev) > > > +static netdev_tx_t sparx5_inject(struct sparx5 *sparx5, > > > + u32 *ifh, > > > + struct sk_buff *skb, > > > + struct net_device *ndev) > > > { > > > int grp = INJ_QUEUE; > > > u32 val, w, count; > > > @@ -172,7 +172,7 @@ static int sparx5_inject(struct sparx5 *sparx5, > > > if (!(QS_INJ_STATUS_FIFO_RDY_GET(val) & BIT(grp))) { > > > pr_err_ratelimited("Injection: Queue not ready: 0x%lx\n", > > > QS_INJ_STATUS_FIFO_RDY_GET(val)); > > > - return -EBUSY; > > > + return NETDEV_TX_BUSY; > > > } > > > > > > /* Indicate SOF */ > > > @@ -234,9 +234,8 @@ netdev_tx_t sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev) > > > sparx5_set_port_ifh(ifh, port->portno); > > > > > > if (sparx5->ptp && skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) { > > > - ret = sparx5_ptp_txtstamp_request(port, skb); > > > - if (ret) > > > - return ret; > > > + if (sparx5_ptp_txtstamp_request(port, skb)) > > > + goto drop; > > > > Is it not possible to return busy also here? > > The reason why I ask this is because of the following case. > > Imagine you need to send a frame and timestamp it, but the HW > > currrently don't have enough slots to store the TX timestamp. In that > > case is better to return BUSY because maybe in short time there will be > > slots. Than just dropping the frame, because if the frame is dropped, > > then there is no chance to get the TX timestamp, and who needs this will > > stop working. > > Yes, we can do that. Thanks for clarifying, I hadn't quite understood > the PTP parts of this. > > > > > > > > > sparx5_set_port_ifh_rew_op(ifh, SPARX5_SKB_CB(skb)->rew_op); > > > sparx5_set_port_ifh_pdu_type(ifh, SPARX5_SKB_CB(skb)->pdu_type); > > > @@ -250,23 +249,27 @@ netdev_tx_t sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev) > > > else > > > ret = sparx5_inject(sparx5, ifh, skb, dev); > > > > > > - if (ret == NETDEV_TX_OK) { > > > - stats->tx_bytes += skb->len; > > > - stats->tx_packets++; > > > + if (ret == NETDEV_TX_BUSY) > > > + goto busy; > > > > > > - if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP && > > > - SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP) > > > - return ret; > > > + stats->tx_bytes += skb->len; > > > + stats->tx_packets++; > > > > > > - dev_kfree_skb_any(skb); > > > - } else { > > > - stats->tx_dropped++; > > > + if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP && > > > + SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP) > > > + return NETDEV_TX_OK; > > > > > > - if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP && > > > - SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP) > > > - sparx5_ptp_txtstamp_release(port, skb); > > > - } > > > - return ret; > > > + dev_consume_skb_any(skb); > > > + return NETDEV_TX_OK; > > > +drop: > > > + stats->tx_dropped++; > > > + dev_kfree_skb_any(skb); > > > + return NETDEV_TX_OK; > > > +busy: > > > + if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP && > > > + SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP) > > > + sparx5_ptp_txtstamp_release(port, skb); > > > + return NETDEV_TX_BUSY; > > > } > > > > > > static enum hrtimer_restart sparx5_injection_timeout(struct hrtimer *tmr) > > > -- > > > 2.34.1 > > > > > > > -- > > /Horatiu -- /Horatiu