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 89FBB13BC0C; Mon, 23 Dec 2024 16:12:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734970324; cv=none; b=SAq/cTLSBaACkPTgOtH1TWyXE5kySGvvOtZpH2ggTMKYVwwk9f7ew1wSib37IxAsXgR12UJJMC2VSfr92/xEkvk7ek1Fk+yhyqlViGuDT4T1/G5LktEkiHchGneADOvy8OR/6bQ+xcur28hNddIchfZ5yhjDTIDekBFyxkpmzvA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734970324; c=relaxed/simple; bh=Q4w4RLxUAkGdhFaybT7GMPl2rSP48Ln1GYP4hJzjzag=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G7EcfY4nBkP7zUZxP7imNpaVS66ZQc1/1eJYmCq0Csu0+2+Sj1um0QBvmJmWxdnIspvZpNk67KlJa0bz/ZIfSvXAgrz2D5SrtFJ5CQtjnCS/htTD1u/e0j7DpJkRVMGqmGVImN0zZPHMvDMXi3twmV+vXSVPjQbdNOA/SSZB974= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qDz/Jihr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qDz/Jihr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EE51AC4CED3; Mon, 23 Dec 2024 16:12:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734970324; bh=Q4w4RLxUAkGdhFaybT7GMPl2rSP48Ln1GYP4hJzjzag=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qDz/Jihr9gEMcYJe4+tlcJGx/sRX83taToecMAmK7zhcbnrD6OcQH3IQ91++iKsbR p917N3MN4zfJwr0DAazpgSlmZfHBcNFNL8Os8Jhh0bPWU4FAAR9hgNqeS+Tb8gVRjw Fiiqy6kB/Qx8SHpzIpY4T40qSjbFuid9eJLziY+s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nikita Yushchenko , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 049/116] net: renesas: rswitch: rework ts tags management Date: Mon, 23 Dec 2024 16:58:39 +0100 Message-ID: <20241223155401.463474181@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241223155359.534468176@linuxfoundation.org> References: <20241223155359.534468176@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nikita Yushchenko [ Upstream commit 922b4b955a03d19fea98938f33ef0e62d01f5159 ] The existing linked list based implementation of how ts tags are assigned and managed is unsafe against concurrency and corner cases: - element addition in tx processing can race against element removal in ts queue completion, - element removal in ts queue completion can race against element removal in device close, - if a large number of frames gets added to tx queue without ts queue completions in between, elements with duplicate tag values can get added. Use a different implementation, based on per-port used tags bitmaps and saved skb arrays. Safety for addition in tx processing vs removal in ts completion is provided by: tag = find_first_zero_bit(...); smp_mb(); ts_skb[tag]> set_bit(...); vs ts_skb[tag]> smp_mb(); clear_bit(...); Safety for removal in ts completion vs removal in device close is provided by using atomic read-and-clear for rdev->ts_skb[tag]: ts_skb = xchg(&rdev->ts_skb[tag], NULL); if (ts_skb) Fixes: 33f5d733b589 ("net: renesas: rswitch: Improve TX timestamp accuracy") Signed-off-by: Nikita Yushchenko Link: https://patch.msgid.link/20241212062558.436455-1-nikita.yoush@cogentembedded.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/renesas/rswitch.c | 74 ++++++++++++++------------ drivers/net/ethernet/renesas/rswitch.h | 13 ++--- 2 files changed, 42 insertions(+), 45 deletions(-) diff --git a/drivers/net/ethernet/renesas/rswitch.c b/drivers/net/ethernet/renesas/rswitch.c index 8abad9bb629e..54aa56c84133 100644 --- a/drivers/net/ethernet/renesas/rswitch.c +++ b/drivers/net/ethernet/renesas/rswitch.c @@ -546,7 +546,6 @@ static int rswitch_gwca_ts_queue_alloc(struct rswitch_private *priv) desc = &gq->ts_ring[gq->ring_size]; desc->desc.die_dt = DT_LINKFIX; rswitch_desc_set_dptr(&desc->desc, gq->ring_dma); - INIT_LIST_HEAD(&priv->gwca.ts_info_list); return 0; } @@ -934,9 +933,10 @@ static int rswitch_gwca_request_irqs(struct rswitch_private *priv) static void rswitch_ts(struct rswitch_private *priv) { struct rswitch_gwca_queue *gq = &priv->gwca.ts_queue; - struct rswitch_gwca_ts_info *ts_info, *ts_info2; struct skb_shared_hwtstamps shhwtstamps; struct rswitch_ts_desc *desc; + struct rswitch_device *rdev; + struct sk_buff *ts_skb; struct timespec64 ts; unsigned int num; u32 tag, port; @@ -946,23 +946,28 @@ static void rswitch_ts(struct rswitch_private *priv) dma_rmb(); port = TS_DESC_DPN(__le32_to_cpu(desc->desc.dptrl)); - tag = TS_DESC_TSUN(__le32_to_cpu(desc->desc.dptrl)); - - list_for_each_entry_safe(ts_info, ts_info2, &priv->gwca.ts_info_list, list) { - if (!(ts_info->port == port && ts_info->tag == tag)) - continue; - - memset(&shhwtstamps, 0, sizeof(shhwtstamps)); - ts.tv_sec = __le32_to_cpu(desc->ts_sec); - ts.tv_nsec = __le32_to_cpu(desc->ts_nsec & cpu_to_le32(0x3fffffff)); - shhwtstamps.hwtstamp = timespec64_to_ktime(ts); - skb_tstamp_tx(ts_info->skb, &shhwtstamps); - dev_consume_skb_irq(ts_info->skb); - list_del(&ts_info->list); - kfree(ts_info); - break; - } + if (unlikely(port >= RSWITCH_NUM_PORTS)) + goto next; + rdev = priv->rdev[port]; + tag = TS_DESC_TSUN(__le32_to_cpu(desc->desc.dptrl)); + if (unlikely(tag >= TS_TAGS_PER_PORT)) + goto next; + ts_skb = xchg(&rdev->ts_skb[tag], NULL); + smp_mb(); /* order rdev->ts_skb[] read before bitmap update */ + clear_bit(tag, rdev->ts_skb_used); + + if (unlikely(!ts_skb)) + goto next; + + memset(&shhwtstamps, 0, sizeof(shhwtstamps)); + ts.tv_sec = __le32_to_cpu(desc->ts_sec); + ts.tv_nsec = __le32_to_cpu(desc->ts_nsec & cpu_to_le32(0x3fffffff)); + shhwtstamps.hwtstamp = timespec64_to_ktime(ts); + skb_tstamp_tx(ts_skb, &shhwtstamps); + dev_consume_skb_irq(ts_skb); + +next: gq->cur = rswitch_next_queue_index(gq, true, 1); desc = &gq->ts_ring[gq->cur]; } @@ -1505,8 +1510,9 @@ static int rswitch_open(struct net_device *ndev) static int rswitch_stop(struct net_device *ndev) { struct rswitch_device *rdev = netdev_priv(ndev); - struct rswitch_gwca_ts_info *ts_info, *ts_info2; + struct sk_buff *ts_skb; unsigned long flags; + unsigned int tag; netif_tx_stop_all_queues(ndev); @@ -1523,12 +1529,13 @@ static int rswitch_stop(struct net_device *ndev) if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS)) iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDID); - list_for_each_entry_safe(ts_info, ts_info2, &rdev->priv->gwca.ts_info_list, list) { - if (ts_info->port != rdev->port) - continue; - dev_kfree_skb_irq(ts_info->skb); - list_del(&ts_info->list); - kfree(ts_info); + for (tag = find_first_bit(rdev->ts_skb_used, TS_TAGS_PER_PORT); + tag < TS_TAGS_PER_PORT; + tag = find_next_bit(rdev->ts_skb_used, TS_TAGS_PER_PORT, tag + 1)) { + ts_skb = xchg(&rdev->ts_skb[tag], NULL); + clear_bit(tag, rdev->ts_skb_used); + if (ts_skb) + dev_kfree_skb(ts_skb); } return 0; @@ -1541,20 +1548,17 @@ static bool rswitch_ext_desc_set_info1(struct rswitch_device *rdev, desc->info1 = cpu_to_le64(INFO1_DV(BIT(rdev->etha->index)) | INFO1_IPV(GWCA_IPV_NUM) | INFO1_FMT); if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) { - struct rswitch_gwca_ts_info *ts_info; + unsigned int tag; - ts_info = kzalloc(sizeof(*ts_info), GFP_ATOMIC); - if (!ts_info) + tag = find_first_zero_bit(rdev->ts_skb_used, TS_TAGS_PER_PORT); + if (tag == TS_TAGS_PER_PORT) return false; + smp_mb(); /* order bitmap read before rdev->ts_skb[] write */ + rdev->ts_skb[tag] = skb_get(skb); + set_bit(tag, rdev->ts_skb_used); skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS; - rdev->ts_tag++; - desc->info1 |= cpu_to_le64(INFO1_TSUN(rdev->ts_tag) | INFO1_TXC); - - ts_info->skb = skb_get(skb); - ts_info->port = rdev->port; - ts_info->tag = rdev->ts_tag; - list_add_tail(&ts_info->list, &rdev->priv->gwca.ts_info_list); + desc->info1 |= cpu_to_le64(INFO1_TSUN(tag) | INFO1_TXC); skb_tx_timestamp(skb); } diff --git a/drivers/net/ethernet/renesas/rswitch.h b/drivers/net/ethernet/renesas/rswitch.h index f2d1cd47187d..0c93ef16b43e 100644 --- a/drivers/net/ethernet/renesas/rswitch.h +++ b/drivers/net/ethernet/renesas/rswitch.h @@ -965,14 +965,6 @@ struct rswitch_gwca_queue { }; }; -struct rswitch_gwca_ts_info { - struct sk_buff *skb; - struct list_head list; - - int port; - u8 tag; -}; - #define RSWITCH_NUM_IRQ_REGS (RSWITCH_MAX_NUM_QUEUES / BITS_PER_TYPE(u32)) struct rswitch_gwca { unsigned int index; @@ -982,7 +974,6 @@ struct rswitch_gwca { struct rswitch_gwca_queue *queues; int num_queues; struct rswitch_gwca_queue ts_queue; - struct list_head ts_info_list; DECLARE_BITMAP(used, RSWITCH_MAX_NUM_QUEUES); u32 tx_irq_bits[RSWITCH_NUM_IRQ_REGS]; u32 rx_irq_bits[RSWITCH_NUM_IRQ_REGS]; @@ -990,6 +981,7 @@ struct rswitch_gwca { }; #define NUM_QUEUES_PER_NDEV 2 +#define TS_TAGS_PER_PORT 256 struct rswitch_device { struct rswitch_private *priv; struct net_device *ndev; @@ -997,7 +989,8 @@ struct rswitch_device { void __iomem *addr; struct rswitch_gwca_queue *tx_queue; struct rswitch_gwca_queue *rx_queue; - u8 ts_tag; + struct sk_buff *ts_skb[TS_TAGS_PER_PORT]; + DECLARE_BITMAP(ts_skb_used, TS_TAGS_PER_PORT); bool disabled; int port; -- 2.39.5