From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f176.google.com (mail-oi1-f176.google.com [209.85.167.176]) (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 54C2A335555 for ; Sat, 31 Jan 2026 15:53:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769874840; cv=none; b=dzLi1HU+VbyP3x3EzeuDFylxZLYhzp54Rtp62aOGLbSy9otVNAWbIku892pBeIJ4KqKu90G2dpzKkFi+ioxXXECu71rHonANbu9ZFduLQVXhION4Eb0oDAmE6RZFxko/4gQXStAJff7PUx1HJ5zGnh478kruOSZa2sL1UUctgjc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769874840; c=relaxed/simple; bh=gPxfc1Or7MT2TMudnUd49s5dM7oxPJDUq2h82ELaFPw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aiXlbN/rerWgJcTZhh+Q0uqMZBdlRgErlUUZ4GjcVW3R6TLm8JVqUgCoCqRQBT1atz7+LV3lNeigKZIn9cIbkbvDEcwQsxzfi7O2MjuLV8dna7V5nnbwwfLcGwNpOP6mwYylXs/mDwOgdcqxUJR/Tmj+EOKQZg45hRnd6awBiwU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=1/qmmZkQ; arc=none smtp.client-ip=209.85.167.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="1/qmmZkQ" Received: by mail-oi1-f176.google.com with SMTP id 5614622812f47-45efe81556fso2139107b6e.2 for ; Sat, 31 Jan 2026 07:53:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1769874837; x=1770479637; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=es4JeecL4qbaq7ZMUlzngsGo7GQdpeuMD9cshqCD5BM=; b=1/qmmZkQfk4elnkxUBpqoKRBAIivPPZdTNmiwiENMhuOS/QNdRTSkGOweWlC9X1KRI cRvXaAIDutBaTjj9p1e6bq24dcSaZWTUEAGKrkDnA9qmF12rg1AjbBar7lrHiWgnxcHo Yi8q3pGLIXW45c5VR53s4g8SyNM8e9IxlrUTed5w+lWMcpEgxWclCMLKyz9KVkTreuLN 0Yh0NLzGV+ycaLPti7ydUniUYwde4pukoltkPUYFveJhVTLezSUwva0ZWtXF3B1REL8/ BY16sbbnabFPkkF65EpRjccfNyYtrWtf88SZH4sbOvzC7WFsZNPaAZDimoFSsTpmuC5M PR1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769874837; x=1770479637; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=es4JeecL4qbaq7ZMUlzngsGo7GQdpeuMD9cshqCD5BM=; b=wQRxnQtbZaT1H3ChHG0t/zaZB7ozuAfvZlVvyu5LJYv9Zn5sU0wpkubfxaeKZWx+pG ssxaiFSJ8AnzdyfhzuECHcEOecMwOcW59zWLaI/GPGQKb/C5vba6fDG5iUmuXdBl0cNY juaVUmfwYV7uV1pqthzNM4q2ca0oc1f1yfG/1nOMYW5eztmPBSlUAuXwP+8JBtULAkdf 8+kZZTSsKB9XB/E/io84qgfhqbX1CXLNB8VipQCS4XgvqFi+/RjGlQVPrtIaJwvCfesW KsTh+3Vy/I/d8Vo1fdbG+wIRNgBxpDfxWuohN4NuEIlGFfdVXT164r03IleGJOZAURZR WKYA== X-Forwarded-Encrypted: i=1; AJvYcCWIC2HWeQzC/OWx3LOsxStnNQG2dBKUZuFI/TPV1zYDPLOnBDKsAR+TCa8YzV49Ohu1X7Vn9W0DxA==@vger.kernel.org X-Gm-Message-State: AOJu0YzCusLAtaib6EJ3m7QVZKiL4Ag2Q/mSp6Ig/vgrQo5oev+xKGFI wIY6jbq7QJPrsHrYwyT4xQv38Nl7kKzbSd+dL1qoPDsjEZPdjX2UvGAHQcLMnWGAxKU= X-Gm-Gg: AZuq6aKjplUb+ZI1bAQ/BLr/BoKgz19S8KI1UTC3l+jp0RX7BrIAn6wK/nqdsSDWHC4 LFVM0xFXZ5oW5NRTPdXiL/vQo0EI9MwLusShBx3DjRueOsDWjHfA+cw5x4o9d0dWu2hgDohOzPM z+4fM5x3hTB7QkoynF8ibQsh78D2c3QAPpo1N6P+W6GX5Ny4rmk36Pn0XpV05sT98DYrLUFCnoc 4kY17r60GWgnVl6CgFnLVmPrIhHrGcyO0yVhYpPyphjxjUrMN7QUigk/kUylO+QHJzxW9JaWKhV 4Sd3mRbMnY6uLMuvlvcXiD0RYMzQwOInKuSwC5QvRwNMe2ME/s171BLZqKKrJ0CNQPaWRlVkLqP JsHtyWvQnlmRMs1+7t5Zq+TDjC3xiB4VE/z38Mzva8UfcMDrfqKdjR22B68p/HT66SFCV73r5W0 UJSnNhtb75d/7oFZJ5rILCpK4tMC8FOhUQph2fLerJyabeXhcQE7Gup9xP2UJpbQsNlmqXQQ== X-Received: by 2002:a05:6808:4fcd:b0:44f:f747:f9f with SMTP id 5614622812f47-45f34cd0c5cmr3020550b6e.36.1769874837163; Sat, 31 Jan 2026 07:53:57 -0800 (PST) Received: from [192.168.1.150] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id 5614622812f47-45f08fb635csm6413741b6e.21.2026.01.31.07.53.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 31 Jan 2026 07:53:56 -0800 (PST) Message-ID: Date: Sat, 31 Jan 2026 08:53:54 -0700 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next RFC 0/3] net: move .getsockopt away from __user buffers To: David Laight , Linus Torvalds Cc: Breno Leitao , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , Willem de Bruijn , metze@samba.org, Stanislav Fomichev , io-uring@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com References: <20260130-getsockopt-v1-0-9154fcff6f95@debian.org> <20260130205227.6fb1d9ad@pumpkin> <20260131153735.3c9273a8@pumpkin> Content-Language: en-US From: Jens Axboe In-Reply-To: <20260131153735.3c9273a8@pumpkin> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/31/26 8:37 AM, David Laight wrote: > On Fri, 30 Jan 2026 17:19:55 -0800 > Linus Torvalds wrote: > >> On Fri, 30 Jan 2026 at 14:40, David Laight wrote: >>> >>> There is not much point making the 'optval' parameter more than >>> a structure of a user and kernel address - one of which will be NULL. >> >> That's exactly what we do *NOT* want. Because people will get it >> wrong, and then we're back to the bad old days where trivial bugs >> result in security issues. > > It can still be a (semi-)transparent structure that code isn't allowed > to change. That is no different from using iov_iter. Then why not just use iov_iter?! FWIW, I fully agree with Linus on this one. We have an existing abstraction, we should use it. We've previously optimized common cases, like ITER_UBUF, if that ended up being important. We're better off using iov_iter and improving that, rather than some new mixed pointer abomination. >> Can you point to an actual case where setsockopt / getsockopt would be >> performance-critical? Typically you do it once or twice. > > IIRC a really horrid one - I think for async io. > That is also one of the few where the supplied length is a lie. Huh? -- Jens Axboe