From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-178.mta1.migadu.com (out-178.mta1.migadu.com [95.215.58.178]) (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 120B342189D for ; Thu, 5 Feb 2026 16:48:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770310089; cv=none; b=dFY+2fevJZtL66pkiMRoBmdwMcFmWSclDYksr8S7I3WDW/aHz/CaEn0XGs28G4adEFvLHmT0/tgbclKw3DNN48CfguVHxa34zTEBbwfS3k8Qbwg0gqOM/L7cx01mt2kGCE3Vi6y3bIP93rzBhPtG6alQacOiN6I6BDH2PssyWf4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770310089; c=relaxed/simple; bh=9s6rlN72umPfzcvftwhUbiWHkEa7FIIwy3ERv4yK7EU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=fgQBb7Kc/pk7Z99nqUEngFHamK7O7azvZXWuw5D9UUmDc0h1K1UIrkjPZEOMlWdTVpu5zdNHj18+X3U5RuYS2qDvFRB1w0C5EtckVdSivdbCIcMTDwjbJsTjdouL8ruRvuEQPAJ1EnS21Pc5CoOUAFM8QPzwPuRrEqAXYYWkAp8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=NAqYauyO; arc=none smtp.client-ip=95.215.58.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="NAqYauyO" Message-ID: <76acd5cc-eb6f-4c56-a5e6-f6413736afbb@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1770310085; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vSwoma4O2xrgSZMEnOzQ9SyuZba4dI6P6unZjdIT0ZA=; b=NAqYauyOnOdnTPlNxN2yN8J2WrIwnB8RffBEJyunEHPilpcgkGbKlVr6ZuZrNxdvba0nQc EBsIkWkdC0ykONGwon5Q1UPmJ9vh7l5KnKOxjyc1kvoydAGGINbY5kN93lunt/XSJWR2P7 atytxicDFNqOPgQM1rBcSU7eFs3zqxc= Date: Thu, 5 Feb 2026 16:48:01 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [Intel-wired-lan] [PATCH iwl-next v3] igb: Retrieve Tx timestamp directly from interrupt for i210 To: Sebastian Andrzej Siewior , Willem de Bruijn , Jakub Kicinski , Paolo Abeni , Eric Dumazet , "David S. Miller" Cc: "Loktionov, Aleksandr" , Kurt Kanzenbach , "Nguyen, Anthony L" , "Kitszel, Przemyslaw" , Paul Menzel , "Gomes, Vinicius" , "netdev@vger.kernel.org" , Richard Cochran , "linux-kernel@vger.kernel.org" , Andrew Lunn , "intel-wired-lan@lists.osuosl.org" , "Keller, Jacob E" References: <20260205-igb_irq_ts-v3-1-2efc7bc4b885@linutronix.de> <20260205100347.ssTBDAI_@linutronix.de> <6a0f4cbb-e8b3-4f0e-b7f1-7f9ca5cba97d@linux.dev> <20260205145104.iWinkXHv@linutronix.de> <66925f09-ef9f-4401-baec-7d4c82a68ce3@linux.dev> <20260205164341.pJvni8kA@linutronix.de> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Vadim Fedorenko In-Reply-To: <20260205164341.pJvni8kA@linutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 05/02/2026 16:43, Sebastian Andrzej Siewior wrote: > On 2026-02-05 16:27:03 [+0000], Vadim Fedorenko wrote: >>> So the only thing that bothers me is the read_lock_bh() in >>> skb_may_tx_timestamp() which deadlocks if the socket is write-locked on >>> the same CPU. >> >> Alright. Now you make me think whether we should enforce OPT_TSONLY >> option on socket which doesn't have CAP_NET_RAW? Then we can get rid of this >> check, and in case sysctl was flipped off - drop TX timestamps as >> it's done now? > > This would "fix" this problem for all users which do deliver the > timestamp from their IRQ handler instead of napi. There are a few of > those… > This would be considered stable material, right? (despite the fact that > we have it for quite some time and nobody complained so far). cc: Willem as he is the author of the check introduced back in 2015. But it's more like a question to maintainers whether it is acceptable way of "fixing" drivers or it's no-go solution