From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 5E8C43B19B3 for ; Thu, 4 Jun 2026 18:53:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780599230; cv=none; b=ujE3/4rfwQaQL7NtLf8Gw/eT6OsmB33nsLPF8JvwlvPxSVm641gAYIwIBUvBREedBpj6QRSh7oI+G8e+uoq4Fgp4LG0LnMhNX8r0TuUo3LD1c2eabPenqK7TM/Qv2ppCQJjNX+xOP7KXmNq+qI2BMudV/FvYD9L1c0RmTgWNdAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780599230; c=relaxed/simple; bh=XsZqKqQ5apgHHhOX9Ab/NdIUELyx46yV4YngdL7eMI8=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=pXUo3nFg+hwp8+dka3Y4d4w/G+9Y1Sc8oEN1fM7W7G2ImMJ79gVcx66a1sT2M+te77d/PQOm4m+nGiBF9zuot2olQR5joljUezkHnZiVFXiUvdmg7gSQ3R6rtSKrgSqc91KK7p07YcI7usnLQpYz/7cTfGhdvCJBV8suoAPC0QE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=di5snAZX; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=Rd+3+vqV; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="di5snAZX"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="Rd+3+vqV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780599228; 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=XsZqKqQ5apgHHhOX9Ab/NdIUELyx46yV4YngdL7eMI8=; b=di5snAZXO+kcuk234ZjHKvIhiVCRlRdCX4HndkXoqWHPRIgeBvz+XqmfQ9QU/eZW4Fsems bH77WFvsjnn+p6at1G+ojqkPGrNflA3XlUNQ7zY/kSbcESSOjrnQ/jBnv8j9KI9BfSwMQH 5qb5WwoSzGmYNGgoXgSs3ZL887p5d10= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-618-hV70DL7cMGmdJLms6-SAUw-1; Thu, 04 Jun 2026 14:53:47 -0400 X-MC-Unique: hV70DL7cMGmdJLms6-SAUw-1 X-Mimecast-MFC-AGG-ID: hV70DL7cMGmdJLms6-SAUw_1780599227 Received: by mail-qk1-f199.google.com with SMTP id af79cd13be357-9158e75cbc0so263950385a.2 for ; Thu, 04 Jun 2026 11:53:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1780599227; x=1781204027; darn=vger.kernel.org; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:from:to:cc:subject :date:message-id:reply-to; bh=XsZqKqQ5apgHHhOX9Ab/NdIUELyx46yV4YngdL7eMI8=; b=Rd+3+vqV5MX6LORT7vjofDFIZj9LrIxC2/Tf4VIpYOyidIwSQiGub4hhBGeI/qi65C p5moG3bSekp6bryyIN657kmnEPot0nRASYj61AyHUs2NbBGtNbv7WrX3N8RhziBR6I+e QthAW/s13W+cPPK5oiNvUCFA09Sh639tntn6qh5IhSBd2oOR9mFEkL1XJ4Aq39Co3ZV0 tKw2v8WYUUpKVUPVQvmLis6AFTKHGcrIHn+Oypg3//aDT9L2b91I+glGcT/vyNRr0jLf mz64HzludgBm443w9VUOHRlGbWpG1Yh2lLJhBFo9xzVSUa4Qq8XSJhGY4GxSNHrDCFtJ jPpQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780599227; x=1781204027; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=XsZqKqQ5apgHHhOX9Ab/NdIUELyx46yV4YngdL7eMI8=; b=RJ+WYPcBtLfawUgq0E5AT9rBVBhcMjhXz+t5XA2gNvNF+nFApXD/IBmY12r5PLOnfl PMoXkA+RnKyJG+b1G9VR9ALtYRGC+w4u+xyes2Z8IFA4NpcV7s9Q3vEhY/H3WLxpqXUp f7ct67FZqYhezv7/hq1cOBKUSexRiaazi7HCRWzUzHZc5glIxoeazOWA9Hvtc19sgxOY A509Qx4TA9hAm3XijwlLAqtm/X4AWHtuhs0kcCDh64ly1V9IkbBM25ZggTIJJvwf1Aw4 IOE1bCrGTWAdhn0UohzpsTrEvVcRId4GZkMsle1jTpe3iGZ4BjlGghaIFAGe/S3cqSR1 Nwng== X-Forwarded-Encrypted: i=1; AFNElJ8KJTVZ0ul3rixIA9W1bIRE4VL3oGBapN0QdCwgoyZetiv5koBSXDKfmzhAZC/RvbAtvZX4easpRzt4dNU=@vger.kernel.org X-Gm-Message-State: AOJu0YzepLdk6HlHHckuSrBHESS7zjAijwsiuv4FAjGvUAQPonjjInbi 2Tk0VDzTPDbseqQAswq7xoWRT0vYoZ0sWQGha4PNcOC7KDbBA2JM9eGhbJTb0Z4gAysUrpFQNgR lzcW2T2PKxfdFbP9ZjOi6ZA6O2CQc3N4OjL1QNHELftVZxeC38He1vCmZiQUUx/ZZcg== X-Gm-Gg: Acq92OHc0QMcvQOtULb7rXSFMhtGMkjPfXVDGPzHvangiaMVR8MFeS7rFtDJHSk+aWt 13Ekc/yw6axa9DLF+0teiTf0fn2xWVMpHggA/g/Z3TY4l+HvnrEKBRZC+q0szQpFeAgLtIGya/G jpr3+zGG+uEPBA7EjURbJyBZ9KN3RpNDtJj/Hs5Vbvv8UGduUgaYcIh/Oyh+XC/1Zi2IZXafhid PhbTM7Z+Fcx4utldsA0ZI/jocv6EtFWWxwvbyF2i0tm/8kFR73/FgoX0dB/SkMFalACU72/JWAj 68rB8ZUMM50xj1nzcxzRXuB27ePilrgBkSr4GihxDQM9OFg6kTa6338gUYgSIh8TP2/J+pXBR5l 9Cient3Ql32BKbMyVgJHVpIKX+lko X-Received: by 2002:a05:620a:40d1:b0:915:a51d:5ee7 with SMTP id af79cd13be357-915a9c496b2mr73287785a.8.1780599226718; Thu, 04 Jun 2026 11:53:46 -0700 (PDT) X-Received: by 2002:a05:620a:40d1:b0:915:a51d:5ee7 with SMTP id af79cd13be357-915a9c496b2mr73280485a.8.1780599226214; Thu, 04 Jun 2026 11:53:46 -0700 (PDT) Received: from [192.168.8.4] ([100.0.180.93]) by smtp.gmail.com with ESMTPSA id af79cd13be357-9158a237330sm683172485a.16.2026.06.04.11.53.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Jun 2026 11:53:45 -0700 (PDT) Message-ID: Subject: Re: [PATCH v17 5/6] rust: sync: Add SetOnce::reset() From: lyude@redhat.com To: Alice Ryhl Cc: dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org, nouveau@lists.freedesktop.org, Alexandre Courbot , Gary Guo , Christian =?ISO-8859-1?Q?K=F6nig?= , driver-core@lists.linux.dev, Miguel Ojeda , Maarten Lankhorst , Simona Vetter , linux-kernel@vger.kernel.org, Sumit Semwal , linux-media@vger.kernel.org, "Rafael J . Wysocki" , Maxime Ripard , Benno Lossin , linaro-mm-sig@lists.linaro.org, Danilo Krummrich , Mukesh Kumar Chaurasiya , Asahi Lina , Daniel Almeida , Greg Kroah-Hartman Date: Thu, 04 Jun 2026 14:53:44 -0400 In-Reply-To: References: <20260603195210.693856-1-lyude@redhat.com> <20260603195210.693856-6-lyude@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2026-06-04 at 11:58 +0000, Alice Ryhl wrote: > On Wed, Jun 03, 2026 at 03:42:34PM -0400, Lyude Paul wrote: > > This function simply drops the contents of the SetOnce, given a > > mutable > > reference - since that proves we have exclusive access to the > > SetOnce. > > Additionally, update the invariants for SetOnce to make it clear as > > to why > > this is safe. > >=20 > > Signed-off-by: Lyude Paul >=20 > This isn't needed, you can just do: >=20 > unsafe { (*this).sgt_res =3D SetOnce::new() }; I realized after sending this I could also just be using ManuallyDrop here instead of adding a reset function, which might be a bit clearer anyhow