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 15D3EC43217 for ; Wed, 16 Nov 2022 11:50:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231659AbiKPLuM (ORCPT ); Wed, 16 Nov 2022 06:50:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239164AbiKPLtG (ORCPT ); Wed, 16 Nov 2022 06:49:06 -0500 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41EB93134D for ; Wed, 16 Nov 2022 03:36:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1668598594; x=1700134594; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=dyU2qAkrd5j8P9k8kXS52mWfnBNIchsNDHH1dozihug=; b=vBhygOiwH2n0ciADA6hfIGOrANj2T9x/IyESBxo5x6blLHXkcr9fFY3E +xuJb9Hl8vKLdlLEbv6cFaUAsvEe0hrH4I/FIO3bQxHbvWBbCxLk9qT9Y lqbh0bduGiUFuxqHlbLBDegVPNH/xSeo5AsQevaRoMllD9unELE8uvFxm mcZcKPUFcMOGZpiyGPLebvJnLfFEkae9KdesTljGsIsh8YcPOu7Eoe5El EA9atbq7xFTnEW02ICZPrx3AL+KKlUfK+xVAxwA4o+cLTs5GlGaqbBUxn Hc5K4rYNaDx4T3hKhZq/AcO/ksTGhK9LsufTKuUsdV2ldOnMtaaOCqEjq A==; X-IronPort-AV: E=Sophos;i="5.96,167,1665471600"; d="scan'208";a="183770716" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa4.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 16 Nov 2022 04:36:31 -0700 Received: from chn-vm-ex02.mchp-main.com (10.10.85.144) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Wed, 16 Nov 2022 04:36:27 -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; Wed, 16 Nov 2022 04:36:27 -0700 Date: Wed, 16 Nov 2022 12:41:15 +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: <20221116114115.eojkihqplenjv6l3@soft-dev3-1> References: <20221116095740.176286-1-casper.casan@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <20221116095740.176286-1-casper.casan@gmail.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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. > 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' > > 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. > > 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