From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 167D23890E9 for ; Thu, 16 Apr 2026 13:27:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776346042; cv=none; b=VcZKTwH84pdFX0kfxy4f/Eyjz6NidTOXA0NO0AOf1lP0NvXbZNpF4ifwKDeECcKvXlw303D9xEvCvmuQxPI9ZeYrnNXcdvmifVHNEKB2CGBQ+slMgR2AK7uD1tnweBdojGkLYUdIYB9XXk4IJjAn9YyZWnDlJjGgJ0IVIIWw9vc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776346042; c=relaxed/simple; bh=U0wkkhyzba+VOCKmZclFLbF+sxUF9Ywi5JITEPUwc7k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=S538/hblFJBQx8862Vve4wPDRgbFZnkwH8YRTYMypf3EjyF1xQ4aflUfm5jB8ofBRAp48cQmr7I9DolGkIRrcwo30V+W/bxI80nASLz2yugf9fc3wWOei2auDhA52CyYHf7v7rXc93WVtneKD8p7Ya/CB30fusqMbhXTxEGWStM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uhuISdkl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uhuISdkl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85735C2BCB3; Thu, 16 Apr 2026 13:27:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776346041; bh=U0wkkhyzba+VOCKmZclFLbF+sxUF9Ywi5JITEPUwc7k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uhuISdklht5GZilmETzaFULIdxNV1HKQOv43zU1TqXTaM2iFcEnAhmG2nvYAMpfOb CpSECYRWMsf1AA6mINE07kqw3DJCJGh3uxAEsTpc8REM+6xDWBQFxBQKfjl7KqlQ3q 400wwd/bJ7x1HluGqaZijuV/IEHpQ7E/dWkEbMsMgskfubgkEDEqgK8R6PzxDA+8Sd mRkbJ7z4qqVL7R4jd0Oeqcvkfr7TyhNEWOFybc33/7MqGQ5mYtKh6ScY7NepOZQMEZ /nIjGgi0CsGPxC7d17ghahd7eXNPh+eIDKcrrKGgLFXzqpMVsn6Xsv+JSZkfrfisWL FfnUpqfyPrDfg== Received: from phl-compute-02.internal (phl-compute-02.internal [10.202.2.42]) by mailfauth.phl.internal (Postfix) with ESMTP id 85D3FF40068; Thu, 16 Apr 2026 09:27:20 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-02.internal (MEProxy); Thu, 16 Apr 2026 09:27:20 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefhedrtddtgdegjeduudcutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpuffrtefokffrpgfnqfghnecuuegr ihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjug hrpeffhffvvefukfhfgggtuggjsehttdertddttddvnecuhfhrohhmpefmihhrhihlucfu hhhuthhsvghmrghuuceokhgrsheskhgvrhhnvghlrdhorhhgqeenucggtffrrghtthgvrh hnpeeuieejieffkeehfeffffdtkeelfeelhefhfefhudehjeehvdffleeuvddufefgkeen ucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehkihhrih hllhdomhgvshhmthhprghuthhhphgvrhhsohhnrghlihhthidqudeiudduiedvieehhedq vdekgeeggeejvdekqdhkrghspeepkhgvrhhnvghlrdhorhhgsehshhhuthgvmhhovhdrnh grmhgvpdhnsggprhgtphhtthhopeefkedpmhhouggvpehsmhhtphhouhhtpdhrtghpthht ohepuhhsrghmrgdrrghrihhfsehlihhnuhigrdguvghvpdhrtghpthhtoheprghkphhmse hlihhnuhigqdhfohhunhgurghtihhonhdrohhrghdprhgtphhtthhopehpvghtvghrgies rhgvughhrghtrdgtohhmpdhrtghpthhtohepuggrvhhiugeskhgvrhhnvghlrdhorhhgpd hrtghpthhtoheplhhjsheskhgvrhhnvghlrdhorhhgpdhrtghpthhtoheprhhpphhtsehk vghrnhgvlhdrohhrghdprhgtphhtthhopehsuhhrvghnsgesghhoohhglhgvrdgtohhmpd hrtghpthhtohepvhgsrggskhgrsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihgr mhdrhhhofihlvghtthesohhrrggtlhgvrdgtohhm X-ME-Proxy: Feedback-ID: i10464835:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 16 Apr 2026 09:27:19 -0400 (EDT) Date: Thu, 16 Apr 2026 14:27:17 +0100 From: Kiryl Shutsemau To: Usama Arif Cc: Andrew Morton , Peter Xu , David Hildenbrand , Lorenzo Stoakes , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , "Liam R . Howlett" , Zi Yan , Jonathan Corbet , Shuah Khan , Sean Christopherson , Paolo Bonzini , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [RFC, PATCH 10/12] userfaultfd: add UFFDIO_SET_MODE for runtime sync/async toggle Message-ID: References: <20260414142354.1465950-11-kas@kernel.org> <20260415150900.3660575-1-usama.arif@linux.dev> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260415150900.3660575-1-usama.arif@linux.dev> On Wed, Apr 15, 2026 at 08:08:59AM -0700, Usama Arif wrote: > > + /* only toggleable features are allowed */ > > + if ((mode.enable | mode.disable) & ~UFFD_FEATURE_TOGGLEABLE) > > + return -EINVAL; > > The commit message states "Only async features that were enabled at > UFFDIO_API time may be toggled." However, the code only checks that > the requested feature is in UFFD_FEATURE_TOGGLEABLE. > > Is it intentional that a user who opened a uffd without > UFFD_FEATURE_MINOR_ASYNC can still enable it later via > UFFDIO_SET_MODE? The comment is stale. Will fix. -- Kiryl Shutsemau / Kirill A. Shutemov