From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-80007.amazon.com (smtp-fw-80007.amazon.com [99.78.197.218]) (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 D07E13CF58 for ; Wed, 21 May 2025 11:44:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747827845; cv=none; b=NMAVlw03wUYfWSKM+FjMKN1N39j2xh2JNriKR5F0UPEhY+zcBEkYU1WMcBM5Bu4Y14AHLPyrajh1TUTIS1XN8ubaO4pZhBO997kM+zR0K3NEySPmgL9XsIVlmirCsCZX0qW+JLanPEBOqyzKCXuEBoo2zMfSnPAyTBSyxoWoIFg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747827845; c=relaxed/simple; bh=J8XmalK6MbOm1ie8kcN5WGmUMUDUHea8EW/A9ylB228=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=YleFrHrpOcuMYbZicLNN5GkS7rafX0m3bi/6PyOJi6Xn+sHWNZ2EkwVfKnGXS9SF5GOHYVC8zVx7aqugRg5fM2+NHVxOkIKjfgMJ5KGM+IRc5ZkUcyXNYIo3jOdwTtoxiA7yzUjtV4Cn16aW26oh47aDevQa4s1ea6C4U0srgfc= 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=t6rCDe1t; arc=none smtp.client-ip=99.78.197.218 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="t6rCDe1t" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1747827844; x=1779363844; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=sU1MI44/hcKTCnvVrxhOeocOjlsqgDWbL9B3bn66tck=; b=t6rCDe1tE9rGa4m9Ex7pvNZjlzurJxKdNSiYOk8nv5EhXc8uuMcc4PpH ui5yVxYciNVfMNzmCRbrvGOtnPdQ8pdvb2kutDNBksNhaaLlY7QrxtdDO jMwfL+ELjPetA44kHJoc0mGjSztmlgkXb9/T4cQBRRr1bR2XlKKDNyqYp JgvV0JadhlGkWTmTki1Y9hMODrQo3kkvNLI8jcIouxS7SOmzgWIzHtbeF ZeD4cl+FIQ03FRhquVC2Q1A5r56PTbbF1jcsIm4PpdLtMAc5cxiPE+00L IdDMI3xwT3Y/7DK2ZFquqS6X8ovzMWGir3vmG5J1zUW+JHTFvAnfIKuX3 Q==; X-IronPort-AV: E=Sophos;i="6.15,303,1739836800"; d="scan'208";a="407651877" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.25.36.210]) by smtp-border-fw-80007.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2025 11:44:02 +0000 Received: from EX19MTAEUC001.ant.amazon.com [10.0.10.100:9128] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.9.121:2525] with esmtp (Farcaster) id 2f572338-53c9-41cf-89ca-c7efa0cc6be2; Wed, 21 May 2025 11:44:01 +0000 (UTC) X-Farcaster-Flow-ID: 2f572338-53c9-41cf-89ca-c7efa0cc6be2 Received: from EX19D005EUA002.ant.amazon.com (10.252.50.11) by EX19MTAEUC001.ant.amazon.com (10.252.51.193) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Wed, 21 May 2025 11:43:58 +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; Wed, 21 May 2025 11:43:47 +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 Subject: [PATCH v9 net-next 2/8] net: ena: PHC silent reset Date: Wed, 21 May 2025 14:42:48 +0300 Message-ID: <20250521114254.369-3-darinzon@amazon.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250521114254.369-1-darinzon@amazon.com> References: <20250521114254.369-1-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: EX19D040UWB004.ant.amazon.com (10.13.138.91) 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