From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-80009.amazon.com (smtp-fw-80009.amazon.com [99.78.197.220]) (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 6B8ED2BF3D3 for ; Tue, 17 Jun 2025 11:06:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.220 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750158407; cv=none; b=ANw7qS9RhE5isIbYIdPvxeRwAYS6+Y9JUrpDQPZOevdKqgrlCvduqIOYvCZeO7ipKZYp0XDsCdf2pR3faUqcei+++a5yohWiH57yH4SnH4MspGb/Mvvmlaxjic7IDJDp+pTX4bYSPDaslimYSPEdwJnJ2W2U0YqBJjM4CprWBRg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750158407; c=relaxed/simple; bh=J8XmalK6MbOm1ie8kcN5WGmUMUDUHea8EW/A9ylB228=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=bR+WzMildchv2TNeZus0845+2og+VAPUJnRJHH6cygkkroAdkp8xDbdVI9TPReaZHO1ekmjphmDfY6w95Auk3d1hgLzQJCqs7wjv6m1o1jEG3fC4J1f1VgODwAcZvYvLL6ehM0wmIil659rgH3OZFUzU0tSpc0BLhkI/T1KLDdo= 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=D7Wg288s; arc=none smtp.client-ip=99.78.197.220 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="D7Wg288s" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1750158406; x=1781694406; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=sU1MI44/hcKTCnvVrxhOeocOjlsqgDWbL9B3bn66tck=; b=D7Wg288sSZqkJRbZSu/MVj/Cu8z+Lcb6J2/eaGIiEy467p5Xa52yVMV0 U0/dH6ovdCf1yUeRLwU7ElPNpNZSDgbwFqrM4CcnL8qet6rYEmvQoQROJ leUFoAexvgPphi6IgasTfqMLSvyRMBzzuo8rwAj+Gu5z1f5dK6ffMUnxr MQGcw4fcUDGwjMX5wO/QHxj6zZyJqFcC79OtxfN8vM+3cJ6zXbgXl6w0l FEg6ds+PdZU4uOiVbbxKW/FyxuEeNfMvkJDg9zSR83Gt2eKecdfDSqlS8 fnXsM14k05C3CmtJT62YdGBIhvITQ4Xex+Xpw5UQD/piiY+SffGx0ACCt w==; X-IronPort-AV: E=Sophos;i="6.16,243,1744070400"; d="scan'208";a="212748927" 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-80009.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jun 2025 11:06:41 +0000 Received: from EX19MTAEUA002.ant.amazon.com [10.0.43.254:26167] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.15.192:2525] with esmtp (Farcaster) id 1206642f-9a7a-4c13-af49-1f36445e4545; Tue, 17 Jun 2025 11:06:40 +0000 (UTC) X-Farcaster-Flow-ID: 1206642f-9a7a-4c13-af49-1f36445e4545 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; Tue, 17 Jun 2025 11:06:40 +0000 Received: from HFA15-G9FV5D3.amazon.com (10.85.143.172) 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; Tue, 17 Jun 2025 11:06:28 +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 v13 net-next 2/9] net: ena: PHC silent reset Date: Tue, 17 Jun 2025 14:05:38 +0300 Message-ID: <20250617110545.5659-3-darinzon@amazon.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250617110545.5659-1-darinzon@amazon.com> References: <20250617110545.5659-1-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: EX19D041UWA003.ant.amazon.com (10.13.139.105) 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