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 X-Spam-Level: X-Spam-Status: No, score=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D5F5C432BE for ; Thu, 12 Aug 2021 21:42:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F01DE60EE2 for ; Thu, 12 Aug 2021 21:42:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237254AbhHLVnT (ORCPT ); Thu, 12 Aug 2021 17:43:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:53912 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229612AbhHLVnM (ORCPT ); Thu, 12 Aug 2021 17:43:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9FCF960C3F; Thu, 12 Aug 2021 21:42:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628804567; bh=XFK4yA210lRZo75z9OXStq+bZH+u7Gcd5Y8jgmMbNi0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sNRXDP7zOvnxT82AJHxWgff2alMlgDxXt3JyqMemm4oCf6DAe2r3/Le+LJI80YYxG p6a4/2DofFqZ3zkXr37lpjYUnd7klRK+CfvQ5zh2G0BMnzNseDOBVGB/ISFGgVw9a+ 1S3lsH91mNpsJaoiun8EzloYa1b8yKMYQkqpcrmdiRAd+H8uA8lf0kWev+hWj13fRT 1ZLpSbA7TP2WpWDXN6aANceR6nMAkX3EVIEWbhzQ/TyyG0braqnfD8VM1KEGq+BeQh /jnZrpj+b7IIwmXJ4mGk5RVCcMwW4tyX1AZEjZ9HpdgsvQfwY2cnswXrBbY18RhK9V HHnhOspED+Faw== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, michael.chan@broadcom.com, prashant@broadcom.com, eddie.wai@broadcom.com, huangjw@broadcom.com, gospo@broadcom.com, edwin.peer@broadcom.com, Jakub Kicinski Subject: [PATCH net v3 3/4] bnxt: make sure xmit_more + errors does not miss doorbells Date: Thu, 12 Aug 2021 14:42:41 -0700 Message-Id: <20210812214242.578039-4-kuba@kernel.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210812214242.578039-1-kuba@kernel.org> References: <20210812214242.578039-1-kuba@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org skbs are freed on error and not put on the ring. We may, however, be in a situation where we're freeing the last skb of a batch, and there is a doorbell ring pending because of xmit_more() being true earlier. Make sure we ring the door bell in such situations. Since errors are rare don't pay attention to xmit_more() and just always flush the pending frames. The busy case should be safe to be left alone because it can only happen if start_xmit races with completions and they both enable the queue. In that case the kick can't be pending. Noticed while reading the code. Fixes: 4d172f21cefe ("bnxt_en: Implement xmit_more.") Signed-off-by: Jakub Kicinski --- v2: - netdev_warn() -> netif_warn() [Edwin] - use correct prod value [Michael] v3: - consolidate the txbuf->skb clearing [Michael] --- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 39 +++++++++++++++-------- drivers/net/ethernet/broadcom/bnxt/bnxt.h | 1 + 2 files changed, 27 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 721b5df36311..389016ea65cf 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c @@ -72,7 +72,8 @@ #include "bnxt_debugfs.h" #define BNXT_TX_TIMEOUT (5 * HZ) -#define BNXT_DEF_MSG_ENABLE (NETIF_MSG_DRV | NETIF_MSG_HW) +#define BNXT_DEF_MSG_ENABLE (NETIF_MSG_DRV | NETIF_MSG_HW | \ + NETIF_MSG_TX_ERR) MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Broadcom BCM573xx network driver"); @@ -365,6 +366,13 @@ static u16 bnxt_xmit_get_cfa_action(struct sk_buff *skb) return md_dst->u.port_info.port_id; } +static void bnxt_txr_db_kick(struct bnxt *bp, struct bnxt_tx_ring_info *txr, + u16 prod) +{ + bnxt_db_write(bp, &txr->tx_db, prod); + txr->kick_pending = 0; +} + static bool bnxt_txr_netif_try_stop_queue(struct bnxt *bp, struct bnxt_tx_ring_info *txr, struct netdev_queue *txq) @@ -413,6 +421,10 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) free_size = bnxt_tx_avail(bp, txr); if (unlikely(free_size < skb_shinfo(skb)->nr_frags + 2)) { + /* We must have raced with NAPI cleanup */ + if (net_ratelimit() && txr->kick_pending) + netif_warn(bp, tx_err, dev, + "bnxt: ring busy w/ flush pending!\n"); if (bnxt_txr_netif_try_stop_queue(bp, txr, txq)) return NETDEV_TX_BUSY; } @@ -537,21 +549,16 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) normal_tx: if (length < BNXT_MIN_PKT_SIZE) { pad = BNXT_MIN_PKT_SIZE - length; - if (skb_pad(skb, pad)) { + if (skb_pad(skb, pad)) /* SKB already freed. */ - tx_buf->skb = NULL; - return NETDEV_TX_OK; - } + goto tx_kick_pending; length = BNXT_MIN_PKT_SIZE; } mapping = dma_map_single(&pdev->dev, skb->data, len, DMA_TO_DEVICE); - if (unlikely(dma_mapping_error(&pdev->dev, mapping))) { - dev_kfree_skb_any(skb); - tx_buf->skb = NULL; - return NETDEV_TX_OK; - } + if (unlikely(dma_mapping_error(&pdev->dev, mapping))) + goto tx_free; dma_unmap_addr_set(tx_buf, mapping, mapping); flags = (len << TX_BD_LEN_SHIFT) | TX_BD_TYPE_LONG_TX_BD | @@ -638,13 +645,15 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) txr->tx_prod = prod; if (!netdev_xmit_more() || netif_xmit_stopped(txq)) - bnxt_db_write(bp, &txr->tx_db, prod); + bnxt_txr_db_kick(bp, txr, prod); + else + txr->kick_pending = 1; tx_done: if (unlikely(bnxt_tx_avail(bp, txr) <= MAX_SKB_FRAGS + 1)) { if (netdev_xmit_more() && !tx_buf->is_push) - bnxt_db_write(bp, &txr->tx_db, prod); + bnxt_txr_db_kick(bp, txr, prod); bnxt_txr_netif_try_stop_queue(bp, txr, txq); } @@ -659,7 +668,6 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) /* start back at beginning and unmap skb */ prod = txr->tx_prod; tx_buf = &txr->tx_buf_ring[prod]; - tx_buf->skb = NULL; dma_unmap_single(&pdev->dev, dma_unmap_addr(tx_buf, mapping), skb_headlen(skb), PCI_DMA_TODEVICE); prod = NEXT_TX(prod); @@ -673,7 +681,12 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) PCI_DMA_TODEVICE); } +tx_free: dev_kfree_skb_any(skb); +tx_kick_pending: + if (txr->kick_pending) + bnxt_txr_db_kick(bp, txr, txr->tx_prod); + txr->tx_buf_ring[txr->tx_prod].skb = NULL; return NETDEV_TX_OK; } diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h index bcf8d00b8c80..ba4e0fc38520 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h @@ -786,6 +786,7 @@ struct bnxt_tx_ring_info { u16 tx_prod; u16 tx_cons; u16 txq_index; + u8 kick_pending; struct bnxt_db_info tx_db; struct tx_bd *tx_desc_ring[MAX_TX_PAGES]; -- 2.31.1