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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