From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8AB3CCCF9EB for ; Wed, 29 Oct 2025 18:08:46 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4cxZxT0vRkz2yjm; Thu, 30 Oct 2025 05:08:45 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2a03:a000:7:0:5054:ff:fe1c:15ff" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1761761325; cv=none; b=dLUWQVjSVlT3pXsS22/m6ihm9AL/N1kMqIAuF+uEQ/LeCWC6kI9MSMKIzTHoTWCZ5b4K6i28LYTE0/92SgKMa6CwyqntV8YoWBtP0sIugGIl4/hb9u9t65dZ6W9XBt9tC/wST6VCMmZl9/sD3L3rbxA9YLMiPL4Z5CPRuQDJE7obItSTbB2qha3KB05H+Ej/Qx1NZpz8gL1RTwJQsBJeOetWqnuYNokI8wJL4G76m4UnWKFGvFxO9Y4CtUpmQe60Wd+ROZEJm4kDEd1M5/F+E7KKw2IN0+IPeaIc3MvzSzOyW9NwOz8Mrm46C+AbSVNasUwcQRX+bDkZx3GOiPHLVg== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1761761325; c=relaxed/relaxed; bh=IRO5/rJhd7y6qAbtBBfOnyjO73djps2jbwQIhCfiClo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dSFsZ8b4TeYdv8bTIzGzTm6bZlGjLe9niJz2GLJ0dpfunht+6o+Pm8ooxXR7FOd0MHWv14WcJWbXwo9K6lzk5lp42EjpoM48gTHDaWK7/eYYd5TGjBAaIcw7Xo+C4Ktpc8tK+AjOn1my16cmhmlpwNwsrdA6cfVAqfOSuQcBF8mY5S4QrUu4NL55Zjr9XTPKLfRUSFUwRs8N3ILHtBNCcUZTtyd2p+IVX3lNeRYyEdUy645htdfzUyRBelY9EVHEwwHlm/YAOHEFO5siCIrojxzj7GT7y2tkoXAFGb5clAL0h7DZ0c0hD1UdgPekamMUF8ufts05qdIaQWhURUVuuA== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; dkim=pass (2048-bit key; unprotected) header.d=linux.org.uk header.i=@linux.org.uk header.a=rsa-sha256 header.s=zeniv-20220401 header.b=qstw6GBW; dkim-atps=neutral; spf=none (client-ip=2a03:a000:7:0:5054:ff:fe1c:15ff; helo=zeniv.linux.org.uk; envelope-from=viro@ftp.linux.org.uk; receiver=lists.ozlabs.org) smtp.mailfrom=ftp.linux.org.uk Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=linux.org.uk header.i=@linux.org.uk header.a=rsa-sha256 header.s=zeniv-20220401 header.b=qstw6GBW; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=ftp.linux.org.uk (client-ip=2a03:a000:7:0:5054:ff:fe1c:15ff; helo=zeniv.linux.org.uk; envelope-from=viro@ftp.linux.org.uk; receiver=lists.ozlabs.org) Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [IPv6:2a03:a000:7:0:5054:ff:fe1c:15ff]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4cxZxS228Vz2yG3 for ; Thu, 30 Oct 2025 05:08:43 +1100 (AEDT) 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=IRO5/rJhd7y6qAbtBBfOnyjO73djps2jbwQIhCfiClo=; b=qstw6GBW0gz7l6/NIZ98+H0BuC LPcTpqbv6qZwuSaVXzFp5+8p3uItulr9RO1wyw6k1QzQVAfHUp/CtKNeZtDmZSm+sgFarRadUCpBK QZrzf7l+w0/cYrUWCRtQcOPwVpTXfR6WfE4DMsjuxuOQV+z0xqou2NBsCOGqqoMuLcuomyEM5NJXa RJQMFf1J+khB5G8o/qb4hoF8XxOYm1SETmvEkodR0rT9kGWkPtyAGI//REIRqkdUm4sCbPWkkDpIi qeQgTiYS1sVVgCHccSx1/k4oTcfdfgLL7bzYX5FyStzF5GG23KhpEBcGZmGVQXrQATbM/9H02+9/9 Dy4tNtaQ==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vEAb5-0000000DNn5-15k7; Wed, 29 Oct 2025 18:08:35 +0000 Date: Wed, 29 Oct 2025 18:08:35 +0000 From: Al Viro To: Ard Biesheuvel Cc: James Bottomley , linux-fsdevel@vger.kernel.org, torvalds@linux-foundation.org, brauner@kernel.org, jack@suse.cz, raven@themaw.net, miklos@szeredi.hu, neil@brown.name, a.hindborg@kernel.org, linux-mm@kvack.org, linux-efi@vger.kernel.org, ocfs2-devel@lists.linux.dev, kees@kernel.org, rostedt@goodmis.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, paul@paul-moore.com, casey@schaufler-ca.com, linuxppc-dev@lists.ozlabs.org, john.johansen@canonical.com, selinux@vger.kernel.org, borntraeger@linux.ibm.com, bpf@vger.kernel.org Subject: Re: [PATCH v2 22/50] convert efivarfs Message-ID: <20251029180835.GT2441659@ZenIV> References: <20251028004614.393374-1-viro@zeniv.linux.org.uk> <20251028004614.393374-23-viro@zeniv.linux.org.uk> <66300d81c5e127e3bca8c6c4d997da386b142004.camel@HansenPartnership.com> <20251028174540.GN2441659@ZenIV> <20251028210805.GP2441659@ZenIV> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Al Viro On Tue, Oct 28, 2025 at 10:34:51PM +0100, Ard Biesheuvel wrote: > I'll let James respond to the specifics of your suggestion, but I'll > just note that this code has a rather convoluted history, as we used > to have two separate pseudo-filesystem drivers, up until a few years > ago: the sysfs based 'efivars' and this efivarfs driver. Given that > modifications in one needed to be visible in the other, they shared a > linked list that shadowed the state of the underlying variable store. > 'efivars' was removed years ago, but it was only recently that James > replaced the linked list in this driver with the dentry cache as the > shadow mechanism. Hmm... Another question about that code: is efivar_get_variable() safe outside of efivar_lock()?