From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout.efficios.com (smtpout.efficios.com [167.114.26.122]) (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 9EB5D608ED; Tue, 13 Feb 2024 20:07:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=167.114.26.122 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707854861; cv=none; b=lTY4Gw7KjiFJG8rgZzo+Gyt/iwVslu3dzYIrOGISg69yXc2l59NA3+JzfGILIHAT6yB0qkFpO05W+nYwDaW2Fo9jzo3FEmCOA8A0t4d06UAUf9PSuOuO8RHA32efdRYCNAN1nVgI6yn120uzkfrJOjGXYin4Vsec+3zuIEWX9XY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707854861; c=relaxed/simple; bh=alxn2JLgjr0DojlbSs97ulyVsMi+u/5tolBs0g7cDYY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=X3/6AJRHdP89cAjyKJomQMTquNNK7lmrPxuzZ8/ANsQ3BjMPEB94sA+WKdaSyCKPd/O7TJPIAmihhfTXrQQJ1ZWargmAYSofDXH/TZBfhB3i+dZX7ge2crOW5UfImS8+HlFB784oylC51YeczlVnLvZS9PK3fATgrRUoXjiZwfk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=ePAd/JKT; arc=none smtp.client-ip=167.114.26.122 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="ePAd/JKT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=efficios.com; s=smtpout1; t=1707854858; bh=alxn2JLgjr0DojlbSs97ulyVsMi+u/5tolBs0g7cDYY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ePAd/JKT5l1npVFtLSV92syRc0qQPEbJ6J160gC0b8WCC4dfDbW3EG1UGk0O5grua 7gWfpMGssKwTjxMg4GUq/aFmu26AMPY3qL5JMZGZ0MHU7n6tPThIRg4j5C77qVIgYj KB5T4c5VUB5nPWPR2oV+Wc19YFld74wNPWRE8yeG4s5GHgkHCm9B9O2XnpcDEnb8BJ FUycIX80oLfkPuXd8okFwOzXpUCcq/BBbcrkxe7atQaJsFX+gMXFJFaC0gPfoRc/oN IakJ/XDGnn2jCaia1G87Xxyc0CAgNn0GXEwkZpH+KCD4H+sd7BKYfjF38aPyzNQkLL FAFRufc1+XJww== Received: from [172.16.0.134] (192-222-143-198.qc.cable.ebox.net [192.222.143.198]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4TZC6f27bSzYsQ; Tue, 13 Feb 2024 15:07:38 -0500 (EST) Message-ID: <457bde90-5ce7-4c60-9268-e5980ddf6cc0@efficios.com> Date: Tue, 13 Feb 2024 15:07:38 -0500 Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 1/8] dax: alloc_dax() return ERR_PTR(-EOPNOTSUPP) for CONFIG_DAX=n Content-Language: en-US To: Dan Williams , Lukas Wunner Cc: Arnd Bergmann , Dave Chinner , linux-kernel@vger.kernel.org, Andrew Morton , Linus Torvalds , Vishal Verma , Dave Jiang , Matthew Wilcox , Russell King , linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-xfs@vger.kernel.org, dm-devel@lists.linux.dev, nvdimm@lists.linux.dev, linux-s390@vger.kernel.org References: <20240212163101.19614-1-mathieu.desnoyers@efficios.com> <20240212163101.19614-2-mathieu.desnoyers@efficios.com> <20240213063226.GA4740@wunner.de> <65cbbdfe19172_29b129476@dwillia2-mobl3.amr.corp.intel.com.notmuch> From: Mathieu Desnoyers In-Reply-To: <65cbbdfe19172_29b129476@dwillia2-mobl3.amr.corp.intel.com.notmuch> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024-02-13 14:07, Dan Williams wrote: > Lukas Wunner wrote: >> On Mon, Feb 12, 2024 at 11:30:54AM -0500, Mathieu Desnoyers wrote: >>> Change the return value from NULL to PTR_ERR(-EOPNOTSUPP) for >>> CONFIG_DAX=n to be consistent with the fact that CONFIG_DAX=y >>> never returns NULL. >> >> All the callers of alloc_dax() only check for IS_ERR(). >> >> Doesn't this result in a change of behavior in all the callers? >> Previously they'd ignore the NULL return value and continue, >> now they'll error out. >> >> Given that, seems dangerous to add a Fixes tag with a v4.0 commit >> and thus risk regressing all stable kernels. > > Oh, good catch, yes that Fixes tag should be: > > 4e4ced93794a dax: Move mandatory ->zero_page_range() check in alloc_dax() > > ...as that was the one that updated the alloc_dax() calling convention > without fixing up the CONFIG_DAX=n case. > > This is a pre-requisite for restoring DAX operation on ARM32. I'll change the Fixes tag in this commit to: Fixes: 4e4ced93794a ("dax: Move mandatory ->zero_page_range() check in alloc_dax()") for v6. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com