From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-9106.amazon.com (smtp-fw-9106.amazon.com [207.171.188.206]) (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 94EC31C8639 for ; Mon, 26 May 2025 06:10:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=207.171.188.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748239827; cv=none; b=RbJYx5z34EqaF9GJX/HhCfFZ7Yvs0OtksXJITm+FwjNLoJk0kDBoYBFNy/SvyIf2M4V1pEHL8l82H9t5zLY0fHz/XZQJeufz8GQc1tKY2pGoLrPjUjZpMAcy05b5I4XQrv0ObOJ2K42Dl2g07sRKf1NjVgntQu8XvCyovS7RNdA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748239827; c=relaxed/simple; bh=J8XmalK6MbOm1ie8kcN5WGmUMUDUHea8EW/A9ylB228=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=YPd2pu1htJxh6T5E9204V8O5534fHz5nq7O2RXBERhNEjCtPmosw7fOw6B186rmX5dJ1CKuX3yPAALVSHvs39xPae6lknbpDXN8wDNqEiVuB+v5dd9BZsOGmwIgigWxizVDSrVlzeHK2JJrXnlFz3cIkg81BlbPphRaY/d4Fs28= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=TOHYp420; arc=none smtp.client-ip=207.171.188.206 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="TOHYp420" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1748239825; x=1779775825; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=sU1MI44/hcKTCnvVrxhOeocOjlsqgDWbL9B3bn66tck=; b=TOHYp420mfyoO+d/ZCe8qUJjMHsw4loDxv7dI/gwGh1TstpOZMNtP4Ec YNq0cB4rGd346U3eeAv/erNIXv7cNTp4O7dYGZ7udqkjvW2Jyueq65js6 fHSX+whWlVptuIMwsMJ7XvYpgNffCb0Z1lo/WDvrcVTyiRIePgdj0Qs9/ bDzKYmXRN0mQ7jAFlnzLIcpFMv2aTLhMKrlo803GbhyiZrlskZwkOtnmm 5oCkY96UKGlGfna9JMmzYv+LTMaDvaEcNeZTzMMOIuw5Xtl8ayanbOQVg Js/EOOK3eZ2jEfY41ef/BMBoT0PeVzYzvIJz8Xc+s3bOa7+8H3Hklr+tR A==; X-IronPort-AV: E=Sophos;i="6.15,315,1739836800"; d="scan'208";a="828389966" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO smtpout.prod.us-east-1.prod.farcaster.email.amazon.dev) ([10.25.36.210]) by smtp-border-fw-9106.sea19.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 May 2025 06:10:17 +0000 Received: from EX19MTAEUA002.ant.amazon.com [10.0.43.254:52919] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.1.135:2525] with esmtp (Farcaster) id 6125f13b-6c44-47d3-ac40-eca8d6a3c9ef; Mon, 26 May 2025 06:10:16 +0000 (UTC) X-Farcaster-Flow-ID: 6125f13b-6c44-47d3-ac40-eca8d6a3c9ef Received: from EX19D005EUA002.ant.amazon.com (10.252.50.11) by EX19MTAEUA002.ant.amazon.com (10.252.50.126) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Mon, 26 May 2025 06:10:16 +0000 Received: from HFA15-G9FV5D3.amazon.com (10.85.143.177) by EX19D005EUA002.ant.amazon.com (10.252.50.11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Mon, 26 May 2025 06:10:04 +0000 From: David Arinzon To: David Miller , Jakub Kicinski , CC: David Arinzon , Eric Dumazet , Paolo Abeni , Simon Horman , "Richard Cochran" , "Woodhouse, David" , "Machulsky, Zorik" , "Matushevsky, Alexander" , Saeed Bshara , "Wilson, Matt" , "Liguori, Anthony" , "Bshara, Nafea" , "Schmeilin, Evgeny" , "Belgazal, Netanel" , "Saidi, Ali" , "Herrenschmidt, Benjamin" , "Kiyanovski, Arthur" , "Dagan, Noam" , "Bernstein, Amit" , "Agroskin, Shay" , "Ostrovsky, Evgeny" , "Tabachnik, Ofir" , "Machnikowski, Maciek" , Rahul Rameshbabu , Gal Pressman , Vadim Fedorenko , Andrew Lunn , Leon Romanovsky , Jiri Pirko Subject: [PATCH v11 net-next 2/8] net: ena: PHC silent reset Date: Mon, 26 May 2025 09:09:12 +0300 Message-ID: <20250526060919.214-3-darinzon@amazon.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250526060919.214-1-darinzon@amazon.com> References: <20250526060919.214-1-darinzon@amazon.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: EX19D044UWB001.ant.amazon.com (10.13.139.171) To EX19D005EUA002.ant.amazon.com (10.252.50.11) Each PHC device kernel registration receives a unique kernel index, which is associated with a new PHC device file located at "/dev/ptp". This device file serves as an interface for obtaining PHC timestamps. Examples of tools that use "/dev/ptp" include testptp [1] and chrony [2]. A reset flow may occur in the ENA driver while PHC is active. During a reset, the driver will unregister and then re-register the PHC device with the kernel. Under race conditions, particularly during heavy PHC loads, the driver’s reset flow might complete faster than the kernel’s PHC unregister/register process. This can result in the PHC index being different from what it was prior to the reset, as the PHC index is selected using kernel ID allocation [3]. While driver rmmod/insmod are done by the user, a reset may occur at anytime, without the user awareness, consequently, the driver might receive a new PHC index after the reset, potentially compromising the user experience. To prevent this issue, the PHC flow will detect the reset during PHC destruction and will skip the PHC unregister/register calls to preserve the kernel PHC index. During the reset flow, any attempt to get a PHC timestamp will fail as expected, but the kernel PHC index will remain unchanged. [1]: https://github.com/torvalds/linux/blob/v6.1/tools/testing/selftests/ptp/testptp.c [2]: https://github.com/mlichvar/chrony [3]: https://www.kernel.org/doc/html/latest/core-api/idr.html Signed-off-by: Amit Bernstein Signed-off-by: David Arinzon --- drivers/net/ethernet/amazon/ena/ena_phc.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_phc.c b/drivers/net/ethernet/amazon/ena/ena_phc.c index 612cf45e..5ce9a32d 100644 --- a/drivers/net/ethernet/amazon/ena/ena_phc.c +++ b/drivers/net/ethernet/amazon/ena/ena_phc.c @@ -108,6 +108,10 @@ static int ena_phc_register(struct ena_adapter *adapter) phc_info = adapter->phc_info; clock_info = &phc_info->clock_info; + /* PHC may already be registered in case of a reset */ + if (ena_phc_is_active(adapter)) + return 0; + phc_info->adapter = adapter; spin_lock_init(&phc_info->lock); @@ -134,7 +138,11 @@ static void ena_phc_unregister(struct ena_adapter *adapter) { struct ena_phc_info *phc_info = adapter->phc_info; - if (ena_phc_is_active(adapter)) { + /* During reset flow, PHC must stay registered + * to keep kernel's PHC index + */ + if (ena_phc_is_active(adapter) && + !test_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags)) { ptp_clock_unregister(phc_info->clock); phc_info->clock = NULL; } -- 2.47.1