From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 1ADF6277C96; Wed, 20 Aug 2025 23:48:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755733703; cv=none; b=BmQVJv3zrX71uVMTERutJsS/cHsr7aYwr7BnaL2RRW90ZxVoKXYeHPx5+e2biOqxcmM12sVJC6kjgyYH8Yrgw1LcCsCqGOthdl8Gc0jhZAn23qgD70p4kOLvSO3AV830Q1zRwyJKQCDgQd02B7yGFbNbp74V+45KqQfpMz49UB0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755733703; c=relaxed/simple; bh=TBIUh3v0aC3WaehxkLqVs1qoFwUO6clBDRYkpK3wpHA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mgE+znOs0Kv7+RjbFIPdZP6iZYOv4VIeaRfvd6txIxS86SqCP5ZuJzEBPEcjNWvYli7Zom4BB0CclFt/TDgDb0hA0UvaDo3QsLxRQg8s4T3hjx429o/gUi4LTpReg1RErM8UqDhOzindQBGcYEmnaU8iFSXBq5J1uhPr7HweELA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=RodaoD32; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="RodaoD32" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=W2KYp9Ckcfqj597p33Lwk5ZySswdeUnAtCa067zilzc=; b=RodaoD32I1/AtcsipP0yTMLiah ogbQDVtg5U7sqAsoe0D62Rqa2nRFaSioDLt+xkSSboPWWiTGy0cLyhmt6x5XQBZmPV1anSuEoBT9f EwdgUfta4h2nSGeIKJEo5iNOb7QuSTtW72v+bMQQX9usToa+LLzn7YWFian57NirX7fI1lOxH2k8K 0G0Rai4qBNAY3j209LF1mlmeBoP0wijRoCb7dcCZ3fHLl2Zo/2hYwv1Hjr/Lk/BPsUfpuifHpCeos afcpGPh+qn/JGKNndSv3apzjeOl6aKpA1kuyQvKi6WWqRpD2UK2E0J0J4VZjhsHlyi062TqsdGErW rx2KL1PA==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uosXP-00000003zKx-1MlO; Wed, 20 Aug 2025 23:48:15 +0000 Date: Thu, 21 Aug 2025 00:48:15 +0100 From: Al Viro To: Linus Torvalds Cc: David Laight , Thomas Gleixner , LKML , Mathieu Desnoyers , Peter Zijlstra , Darren Hart , Davidlohr Bueso , =?iso-8859-1?Q?Andr=E9?= Almeida , x86@kernel.org, Christian Brauner , Jan Kara , linux-fsdevel@vger.kernel.org Subject: Re: [patch 0/4] uaccess: Provide and use helpers for user masked access Message-ID: <20250820234815.GA656679@ZenIV> References: <20250813150610.521355442@linutronix.de> <20250817144943.76b9ee62@pumpkin> <20250818222106.714629ee@pumpkin> <20250818222111.GE222315@ZenIV> <20250819003908.GF222315@ZenIV> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20250819003908.GF222315@ZenIV> Sender: Al Viro On Tue, Aug 19, 2025 at 01:39:09AM +0100, Al Viro wrote: > I'm still trying to come up with something edible for lock_mount() - > the best approximation I've got so far is > > CLASS(lock_mount, mp)(path); > if (IS_ERR(mp.mp)) > bugger off ... and that does not work, since DEFINE_CLASS() has constructor return a value that gets copied into the local variable in question. Which is unusable for situations when a part of what constructor is doing is insertion of that local variable into a list. __cleanup() per se is still usable, but... no DEFINE_CLASS for that kind of data structures ;-/