From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752685AbdCPOH4 (ORCPT ); Thu, 16 Mar 2017 10:07:56 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56302 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751478AbdCPOHy (ORCPT ); Thu, 16 Mar 2017 10:07:54 -0400 Date: Thu, 16 Mar 2017 23:07:39 +0900 From: Greg KH To: Michal Sojka Cc: linux-kernel@vger.kernel.org, lisovy@gmail.com Subject: Re: [PATCH 1/3] uio: Allow handling of non page-aligned memory regions Message-ID: <20170316140739.GC30080@kroah.com> References: <20170307140948.30099-1-sojkam1@fel.cvut.cz> <20170316082012.GA23493@kroah.com> <87k27pqtj5.fsf@steelpick.2x.cz> <20170316132548.GB10184@kroah.com> <87h92tqrbu.fsf@steelpick.2x.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87h92tqrbu.fsf@steelpick.2x.cz> User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 16, 2017 at 02:33:25PM +0100, Michal Sojka wrote: > On Thu, Mar 16 2017, Greg KH wrote: > > On Thu, Mar 16, 2017 at 01:45:50PM +0100, Michal Sojka wrote: > >> On Thu, Mar 16 2017, Greg KH wrote: > >> > On Tue, Mar 07, 2017 at 03:09:46PM +0100, Michal Sojka wrote: > >> >> Since commit b65502879556 ("uio: we cannot mmap unaligned page > >> >> contents") addresses and sizes of UIO memory regions must be > >> >> page-aligned. If the address in the BAR register is not page-aligned, > >> >> the mentioned commit forces the UIO driver to round the address down > >> >> to the page size. Then, there is no easy way for user-space to learn > >> >> the offset of the actual memory region within the page, because the > >> >> offset seen in the sysfs is calculated from the rounded address and > >> >> thus it is always zero. > >> >> > >> >> Fix that problem by including the offset in struct uio_mem. UIO > >> >> drivers can set this field and its value is reported via sysfs. > >> > > >> > It is, where? > >> > >> /sys/class/uio/uio0/maps/map0/offset > > > > Did you change the Documentation/ABI entry for it? > > No, because it seems that UIO is not documented there. Wow, it really isn't, that sucks, I messed up :( But, the uio-howto.rst file should probably be updated, right? thanks, greg k-h