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 62FADC4338F for ; Wed, 11 Aug 2021 21:38:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 43C3B60F11 for ; Wed, 11 Aug 2021 21:38:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232268AbhHKVin (ORCPT ); Wed, 11 Aug 2021 17:38:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:34618 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232191AbhHKVih (ORCPT ); Wed, 11 Aug 2021 17:38:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C2DDC6109E; Wed, 11 Aug 2021 21:38:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628717892; bh=2fn+0OkdrN4knwhxjuBycRFDiUcc18ZikiSmxRSRFF8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tWWOiIEQ2e6KazQwwR56kY4CNWoIam7u2SeQ8+wnfX86M8c2TYt9m9twRsV/uFO8z vB9YYqXToC+FmwTmcsa06qCvjRc3L3lOpsO+/O43fvEyoPTaBIeWH4BcSHfGPpCWfN Tag6BupcvOG5Q3adeVH8C3fJk39950dRsFEDntDUOQ89gENZuiuGzR4OqrmBkJoGpS Kab5hFOB3FOJWXRAXThJjybx8VraO0sNhIS3o5vwRWG6rcgkVkDOZQE/sDPSHyPjrz 7EvTTdsa0MLO1EKMzEVb430WTuCz0AMof5b5sdnwzGd6nbcx8OYPn7UaV7hr1VuHHS BbWzFLh5eo3ww== From: Jakub Kicinski To: davem@davemloft.net Cc: michael.chan@broadcom.com, huangjw@broadcom.com, eddie.wai@broadcom.com, prashant@broadcom.com, gospo@broadcom.com, netdev@vger.kernel.org, edwin.peer@broadcom.com, Jakub Kicinski Subject: [PATCH net v2 3/4] bnxt: make sure xmit_more + errors does not miss doorbells Date: Wed, 11 Aug 2021 14:37:48 -0700 Message-Id: <20210811213749.3276687-4-kuba@kernel.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210811213749.3276687-1-kuba@kernel.org> References: <20210811213749.3276687-1-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] --- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 36 +++++++++++++++-------- drivers/net/ethernet/broadcom/bnxt/bnxt.h | 1 + 2 files changed, 25 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 52f5c8405e76..79bbd6ec7ef7 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"); @@ -367,6 +368,13 @@ 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 netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) { struct bnxt *bp = netdev_priv(dev); @@ -396,6 +404,8 @@ 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)) { netif_tx_stop_queue(txq); + if (net_ratelimit() && txr->kick_pending) + netif_warn(bp, tx_err, dev, "bnxt: ring busy!\n"); return NETDEV_TX_BUSY; } @@ -516,21 +526,16 @@ 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 | @@ -617,13 +622,15 @@ 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); netif_tx_stop_queue(txq); @@ -661,7 +668,12 @@ 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: + tx_buf->skb = NULL; + if (txr->kick_pending) + bnxt_txr_db_kick(bp, txr, txr->tx_prod); return NETDEV_TX_OK; } diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h index 9c3324e76ff7..7b989b6e4f6e 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h @@ -799,6 +799,7 @@ 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