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 F3399329C6C; Fri, 13 Feb 2026 08:28:06 +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=1770971287; cv=none; b=REVLxivWdMEOsVi9SLTWhcaKpbRxwPW1gb+6RsSP+O9FODFmzXSMKv+FtilKTenPG0XqSdCyGsYzlIcMDnrrC07A7P/5UDKgM2nUBFv7kR/6k+KTtN1Okn7P2uEip3XD+cJjowX34mS0n4ITcrZ+YZsHg/imzZyFf/ddqSmLpXM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770971287; c=relaxed/simple; bh=a5f9nQfti0Tq2jhHV6xeyiyqksD8zxt8zYDfrv1119w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eZ/2eSaYGf1I89E/jwP/Imifj5nHughZMoa0Zp3XwYKqgUZNbthwPd+BCrnErlq0IimdGpj1Swioh6ehe1cNf8lOJ+1DW0pIMPQgnsFpqN8mcm6zzAByOEVLpohh9TeiVjaaLMCEjypW2COstm55iv6jSe5pg1fvBZBkDN7WErk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K7CPZY4f; 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="K7CPZY4f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EF88C116C6; Fri, 13 Feb 2026 08:28:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770971286; bh=a5f9nQfti0Tq2jhHV6xeyiyqksD8zxt8zYDfrv1119w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=K7CPZY4fO8L37RcqMooOZp6M/1J4jq55hCH7xhyO8/eN6Uohf64LOjhAH+pEv9o33 mvRBITdPBpQJ2/mMg500hq9e+j/FW0JAqcGFWvLEgohBG8nvN1K7dO9z4ioV6RZ13C KQJHJDvKvOGGEDhyMWVpHpwkk8S5r/N9/+zMwW4jKr6qcmTSyApe/jSoQlvce7/CaK YoX9ipRfxcidgsi4fgRFUr6k0Pr+69INXGnH97FU6scb886xnUNsQroSaGZ1Qmbmh5 s0wx22PEml8b2I+FNqGZ0eH8CsPkUpGU72ppiUaN6B3vlyGYJSSWWMkl29ZKH0mvol taWWQsP6DC3Ig== Received: from johan by rho.lan with local (Exim 4.98.2) (envelope-from ) id 1vqoWr-000000008Fr-2BJa; Fri, 13 Feb 2026 09:27:58 +0100 Date: Fri, 13 Feb 2026 09:27:57 +0100 From: Johan Hovold To: "Paul E. McKenney" Cc: Tzung-Bi Shih , Bartosz Golaszewski , Greg Kroah-Hartman , "Rafael J . Wysocki" , Danilo Krummrich , Shuah Khan , Laurent Pinchart , linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, linux-kselftest@vger.kernel.org, Bartosz Golaszewski Subject: Re: [PATCH] revocable: hide the implementation details from users Message-ID: References: <20260206103216.38623-1-bartosz.golaszewski@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kselftest@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: On Tue, Feb 10, 2026 at 08:59:20PM -0800, Paul E. McKenney wrote: > On Wed, Feb 11, 2026 at 02:05:26AM +0000, Tzung-Bi Shih wrote: > > On Mon, Feb 09, 2026 at 05:13:17AM -0600, Bartosz Golaszewski wrote: > > > On Fri, 6 Feb 2026 23:02:44 +0100, "Paul E. McKenney" said: > > > > On Fri, Feb 06, 2026 at 11:32:06AM +0100, Bartosz Golaszewski wrote: > > > >> Could you please take a look and say if the design looks sane to you? > > > >> Especially the double SRCU on the revocable_provider. > > > > > > > > The first patch in the above URL adds SRCU, and the other > > > > two add various tests. I do not see a double SRCU, just an > > > > srcu_read_lock() in revocable_try_access() and an srcu_read_unlock() > > > > in revocable_withdraw_access(). > > > This series didn't have it yet, it appeared as a fix to a race reported after > > > it was queued, sorry for the confusion. I'm talking about this bit[1] here. > > > It returns an __rcu-annotated pointer, forcing the user to keep and manage it. > > Please hold off on reviewing the patch and the "double SRCU" usage for now. > > I'll remove the second RCU in the next version, which should serve as a > > better starting point for a clean review. In case Paul or anyone else reading this wonders, the "revocable" code was reverted last Friday so that's why the links Bartosz posted are broken: https://lore.kernel.org/lkml/20260204142849.22055-1-johan@kernel.org/ Johan