From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from www381.your-server.de ([78.46.137.84]:50215 "EHLO www381.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752505AbcEaODf (ORCPT ); Tue, 31 May 2016 10:03:35 -0400 Subject: Re: [RFC 6/7] iio: Refuse to register triggers with duplicate names To: Crestez Dan Leonard , Jonathan Cameron , linux-iio@vger.kernel.org References: <643ac0601a74fadc842ccb83c8f3741293ef7299.1464027859.git.leonard.crestez@intel.com> <08913c84-b83f-8163-c766-5935a202b3c2@kernel.org> <96cbaba0-29bb-7282-3e30-b4ebdd859b99@intel.com> Cc: linux-kernel@vger.kernel.org, Hartmut Knaack , Peter Meerwald-Stadler , Daniel Baluta From: Lars-Peter Clausen Message-ID: <574D99B0.6000105@metafoo.de> Date: Tue, 31 May 2016 16:03:28 +0200 MIME-Version: 1.0 In-Reply-To: <96cbaba0-29bb-7282-3e30-b4ebdd859b99@intel.com> Content-Type: text/plain; charset=windows-1252 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 05/30/2016 02:49 PM, Crestez Dan Leonard wrote: > On 05/29/2016 10:48 PM, Jonathan Cameron wrote: >> On 23/05/16 19:40, Crestez Dan Leonard wrote: >>> The trigger name is documented as unique but drivers are currently >>> allowed to register triggers with duplicate names. This should be >>> considered a bug since it makes the 'current_trigger' interface >>> unusable. >>> >>> Signed-off-by: Crestez Dan Leonard >> This feels like the right approach to my mind (and should have been there >> all along - oops). >> >> However, we do need to avoid breaking userspace. It's ugly but for those 3 drivers >> can we assume that using more than one on a board was impossible before this series >> and as such play a slight game in which we don't change the trigger name they >> are exporting, unless that name is already in use? >> >> It's ugly but it gets us the nicest solution for all drivers for a bit of ugly in >> 3 of them... > > How would that look like? I guess I could handle -EEXIST from > iio_trigger_register and try again with another name? Unfortunately the > name is initialized at alloc time while uniqueness can only be checked > at register time. This would require some refactoring in drivers for > devices I don't have. > > An alternative would be to just submit patches 4/5 and only give a > warning when non-unique trigger names are used. After all, iio device > names are not unique, the easy way would be to give up on this guarantee > for trigger names as well. > I'd say apply this patch keep things as they are in the drivers and if somebody creates a board with more than one of those devices let them come up with a fix.