From patchwork Thu Apr 18 07:36:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Xing X-Patchwork-Id: 13634282 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A8E7656462 for ; Thu, 18 Apr 2024 07:36:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713425779; cv=none; b=DOpPKt8RGWGm+WUnEJD3V5byWiUNNoEz/+0P46KEUX9ownngQjbcvKdfAIuhbSvR93WnVwSGTHPLqh2psRPhAv3QyH2FwHlx0uXxc9OTQ9jMd43zAV6nGcpE9POKqsGEe9qxhgtzlG4OK1O4e+Hxm8x+DG8Rtko63WTqIRhcCRs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713425779; c=relaxed/simple; bh=FEFmTqiSFB0xi75Lvv3A7nJ4J3W1Xw4/8ttAG32oOdk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=WZkp7CDCz7azfD/MffvQ035GOCylCBFdhs3aE1HUKStEdAG6GJ08oYF1yoLonhb/7nzu2RKwpB+mtquO/LZW1oY1G5eiEIw7VmJEE4nY0096A7l2KEJUrE92yvSXxh76bkxTC/sIvInGU2eyEas5+D/nfSZ9TtEA98iEOnQVXe8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=D4MHI2bw; arc=none smtp.client-ip=209.85.214.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="D4MHI2bw" Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-1e65b29f703so4892105ad.3 for ; Thu, 18 Apr 2024 00:36:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1713425778; x=1714030578; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=DBehbCdCyWW8txnp4pZNDxM/Mx+V9ByxE1Nv3M+HJek=; b=D4MHI2bw07X5vJntF4UdNgQLWEhdjsdanOlDUaJ4zbbJg9T13Gf5eu+N4tDIAavDDB rRQ+6485uz4vpoEby3WmiFwCnJG4YSX7Hr315AVdGZuvT4D/bHl/Esnx7ewfeL7x7hDC kQJHMC0AcpmVU1/p6N75bZEQ2TQuxCru5NRtOvHG23jsHpvaLphS25MguOce7RafMEtl 5TNIkpsF4eAWJyRGQagGRDwJkQLUeoehq37Lc+7P0lFSa7OZ7EKW9GoASHMxkL1gL2In n1XlUi60LaeghdwL83BdSZjn6FkMyXNzabgFcPvJiavT84kYp76dZt7hV8mIHP+yWExN 82oQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1713425778; x=1714030578; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=DBehbCdCyWW8txnp4pZNDxM/Mx+V9ByxE1Nv3M+HJek=; b=wkt/2cX97t5rDSfw6y9cMeWwHWk4r/WRu63eXEgT8ndTM/1rmnwtIVDuzhSP4Qlgr+ F72zbjoS6z4gEsCkCADq5CAwSfVUtpQNok3yWDpWBib6oTjHda1/1gsdd4FFiZVNzW7c AsbSZaP7aGZFSmYCF9RV3GFwqsxH1LxRpjasbXSaRd/dF8D+S86Ofaj07HzIuSBROThx Gc0WDvZZcajiMRok4uOjAod2rum1UIlEUprvhO/NqWKj6VBFRwu5VD/q2LopbSJ7OU8n EVRYpmc2oz9ZMmHI4joQAylVO1XtRp0DqH0U8ZHfe0s3JvDsMvefWy7kIJADlmuB1aZJ 1N5Q== X-Gm-Message-State: AOJu0Yz365r16HpGfoJoFRlAySro5pwohZki/YbOmEMMS3E/GZkfhs5r +21/APLX6DqQj5MNRa5DzQEcso1eWUu2UfYtnBzgsvXJ+S2W2m4i X-Google-Smtp-Source: AGHT+IF7Yff+KHvjATsuFYkHY3u1kmEmAmJLiYxFlUk8OFwGCBrSjwOts17Cu32vk8JhsZvjcgLo3Q== X-Received: by 2002:a17:903:41c9:b0:1e2:61ca:9449 with SMTP id u9-20020a17090341c900b001e261ca9449mr2689550ple.40.1713425774392; Thu, 18 Apr 2024 00:36:14 -0700 (PDT) Received: from KERNELXING-MB0.tencent.com ([43.132.141.24]) by smtp.gmail.com with ESMTPSA id j9-20020a17090276c900b001e26ba8882fsm841756plt.287.2024.04.18.00.36.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Apr 2024 00:36:13 -0700 (PDT) From: Jason Xing To: edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, davem@davemloft.net, horms@kernel.org Cc: netdev@vger.kernel.org, kerneljasonxing@gmail.com, Jason Xing Subject: [PATCH net-next v3 2/3] net: rps: protect filter locklessly Date: Thu, 18 Apr 2024 15:36:02 +0800 Message-Id: <20240418073603.99336-3-kerneljasonxing@gmail.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20240418073603.99336-1-kerneljasonxing@gmail.com> References: <20240418073603.99336-1-kerneljasonxing@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org From: Jason Xing As we can see, rflow->filter can be written/read concurrently, so lockless access is needed. Signed-off-by: Jason Xing Reviewed-by: Eric Dumazet --- net/core/dev.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 58e0da91bfef..ed6efef01582 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4524,9 +4524,9 @@ set_rps_cpu(struct net_device *dev, struct sk_buff *skb, goto out; old_rflow = rflow; rflow = &flow_table->flows[flow_id]; - rflow->filter = rc; - if (old_rflow->filter == rflow->filter) - old_rflow->filter = RPS_NO_FILTER; + WRITE_ONCE(rflow->filter, rc); + if (old_rflow->filter == rc) + WRITE_ONCE(old_rflow->filter, RPS_NO_FILTER); out: #endif head = READ_ONCE(per_cpu(softnet_data, next_cpu).input_queue_head); @@ -4666,7 +4666,7 @@ bool rps_may_expire_flow(struct net_device *dev, u16 rxq_index, if (flow_table && flow_id <= flow_table->mask) { rflow = &flow_table->flows[flow_id]; cpu = READ_ONCE(rflow->cpu); - if (rflow->filter == filter_id && cpu < nr_cpu_ids && + if (READ_ONCE(rflow->filter) == filter_id && cpu < nr_cpu_ids && ((int)(READ_ONCE(per_cpu(softnet_data, cpu).input_queue_head) - READ_ONCE(rflow->last_qtail)) < (int)(10 * flow_table->mask)))