From patchwork Thu Feb 15 20:06:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 13559120 X-Patchwork-Delegate: snitzer@redhat.com 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 0728113A274; Thu, 15 Feb 2024 20:06:13 +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=1708027574; cv=none; b=qKrADJAHZdQvdwwsBro0VIGzVkYJQNhyw5dJAM8j/DsS9WM+l9sSpDRqWAEJkPvgZU3tjPTV+BcpOYntW1J5xXyiiqLLHlYvbbFw0lb1CMpJIRFrrnnLyAP3qFyXUV76umvIJNgvk5mv4Ci4FZEkYCw+2m9X0gzzAFRNSJ9V5P8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708027574; c=relaxed/simple; bh=wqT4aymXjlZf5+V0ppfRJC5QBB6CkcAiMPoc++byL8g=; h=Date:To:From:Subject:Message-Id; b=hugPxN50TEKxs9aSeImbF7fLNmScR6z4vNElahRV+v/MnTNvX1PdW7ohFzD1T01UB3dqmgcmqBkkowT1UekA41tMY2dUz1aL+R1RFXl3y+U8QnlIARtn2p63nnroaBPQCFUvpmMAhX7vSJ5jPMC7fTJDju5tde/8c0Rf371J/58= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=e+fR6QKU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="e+fR6QKU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD900C433C7; Thu, 15 Feb 2024 20:06:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1708027573; bh=wqT4aymXjlZf5+V0ppfRJC5QBB6CkcAiMPoc++byL8g=; h=Date:To:From:Subject:From; b=e+fR6QKUW0sMufS+D+vfBlp8NATuT8Kj9V94cEB2AG8smcB6/THOnfrMaHY7XdALM wa3S5POIQ01MSw/StbDgWPh2wxZZD6XYHYCg9QB6w2H15g/Qd6x6/HIBQaJXQ/OSGg Mv4oMzolCHFXC+kvMva8NnpIYI/ksBMSYWEh6v2w= Date: Thu, 15 Feb 2024 12:06:13 -0800 To: mm-commits@vger.kernel.org,willy@infradead.org,vishal.l.verma@intel.com,snitzer@kernel.org,mpatocka@redhat.com,lkp@intel.com,linux@armlinux.org.uk,hch@lst.de,hca@linux.ibm.com,dm-devel@lists.linux.dev,david@fromorbit.com,dave.jiang@intel.com,dan.j.williams@intel.com,arnd@arndb.de,agk@redhat.com,mathieu.desnoyers@efficios.com,akpm@linux-foundation.org From: Andrew Morton Subject: + dax-check-for-data-cache-aliasing-at-runtime.patch added to mm-unstable branch Message-Id: <20240215200613.BD900C433C7@smtp.kernel.org> Precedence: bulk X-Mailing-List: dm-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: dax: Check for data cache aliasing at runtime has been added to the -mm mm-unstable branch. Its filename is dax-check-for-data-cache-aliasing-at-runtime.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/dax-check-for-data-cache-aliasing-at-runtime.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Mathieu Desnoyers Subject: dax: Check for data cache aliasing at runtime Date: Thu, 15 Feb 2024 09:46:31 -0500 Replace the following fs/Kconfig:FS_DAX dependency: depends on !(ARM || MIPS || SPARC) By a runtime check within alloc_dax(). This runtime check returns ERR_PTR(-EOPNOTSUPP) if the @ops parameter is non-NULL (which means the kernel is using an aliased mapping) on an architecture which has data cache aliasing. Change the return value from NULL to PTR_ERR(-EOPNOTSUPP) for CONFIG_DAX=n for consistency. This is done in preparation for using cpu_dcache_is_aliasing() in a following change which will properly support architectures which detect data cache aliasing at runtime. Link: https://lkml.kernel.org/r/20240215144633.96437-8-mathieu.desnoyers@efficios.com Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches") Signed-off-by: Mathieu Desnoyers Reviewed-by: Dan Williams Cc: Dan Williams Cc: Vishal Verma Cc: Dave Jiang Cc: Matthew Wilcox Cc: Arnd Bergmann Cc: Russell King Cc: Alasdair Kergon Cc: Christoph Hellwig Cc: Dave Chinner Cc: Heiko Carstens Cc: kernel test robot Cc: Michael Sclafani Cc: Mike Snitzer Cc: Mikulas Patocka Signed-off-by: Andrew Morton --- drivers/dax/super.c | 10 ++++++++++ fs/Kconfig | 1 - 2 files changed, 10 insertions(+), 1 deletion(-) --- a/drivers/dax/super.c~dax-check-for-data-cache-aliasing-at-runtime +++ a/drivers/dax/super.c @@ -451,6 +451,16 @@ struct dax_device *alloc_dax(void *priva dev_t devt; int minor; + /* + * Unavailable on architectures with virtually aliased data caches, + * except for device-dax (NULL operations pointer), which does + * not use aliased mappings from the kernel. + */ + if (ops && (IS_ENABLED(CONFIG_ARM) || + IS_ENABLED(CONFIG_MIPS) || + IS_ENABLED(CONFIG_SPARC))) + return ERR_PTR(-EOPNOTSUPP); + if (WARN_ON_ONCE(ops && !ops->zero_page_range)) return ERR_PTR(-EINVAL); --- a/fs/Kconfig~dax-check-for-data-cache-aliasing-at-runtime +++ a/fs/Kconfig @@ -60,7 +60,6 @@ endif # BLOCK config FS_DAX bool "File system based Direct Access (DAX) support" depends on MMU - depends on !(ARM || MIPS || SPARC) depends on ZONE_DEVICE || FS_DAX_LIMITED select FS_IOMAP select DAX