From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liam Girdwood Subject: Re: [PATCH 2/3] ucm: add a FIXME comment Date: Wed, 11 Feb 2015 16:16:11 +0000 Message-ID: <1423671371.7654.27.camel@loki> References: <1423600954-8751-1-git-send-email-tanu.kaskinen@linux.intel.com> <1423600954-8751-3-git-send-email-tanu.kaskinen@linux.intel.com> <1423655080.2747.3.camel@tkkaskin-mobl3.ger.corp.intel.com> <1423661646.2747.5.camel@tkkaskin-mobl3.ger.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by alsa0.perex.cz (Postfix) with ESMTP id C8D112605DC for ; Wed, 11 Feb 2015 17:16:48 +0100 (CET) In-Reply-To: <1423661646.2747.5.camel@tkkaskin-mobl3.ger.corp.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Tanu Kaskinen Cc: Takashi Iwai , alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On Wed, 2015-02-11 at 15:34 +0200, Tanu Kaskinen wrote: > On Wed, 2015-02-11 at 14:01 +0100, Takashi Iwai wrote: > > At Wed, 11 Feb 2015 13:44:40 +0200, > > Tanu Kaskinen wrote: > > > > > > On Wed, 2015-02-11 at 12:38 +0100, Takashi Iwai wrote: > > > > At Tue, 10 Feb 2015 22:42:33 +0200, > > > > Tanu Kaskinen wrote: > > > > > > > > > > I'm pretty sure the current code will crash with some inputs, but I > > > > > don't know what the original author intended this code to do, so I > > > > > don't know how to fix it. > > > > > --- > > > > > src/ucm/main.c | 8 ++++++++ > > > > > 1 file changed, 8 insertions(+) > > > > > > > > > > diff --git a/src/ucm/main.c b/src/ucm/main.c > > > > > index 3924aee..62bc374 100644 > > > > > --- a/src/ucm/main.c > > > > > +++ b/src/ucm/main.c > > > > > @@ -317,6 +317,14 @@ static int execute_sequence(snd_use_case_mgr_t *uc_mgr, > > > > > uc_error("cdev is not defined!"); > > > > > return err; > > > > > } > > > > > + /* FIXME: If cdev1 is NULL and cdev2 is not, > > > > > + * then set cdev to cdev1... makes no sense! > > > > > + * Also, what if both cdev1 and cdev2 are NULL? > > > > > + * What should happen? Later in this function we > > > > > + * call open_ctl(), which assumes non-NULL cdev, > > > > > + * so leaving cdev to NULL here is not an > > > > > + * option (or at least cdev has to be checked > > > > > + * before calling open_ctl()). */ > > > > > if (cdev1 == NULL || cdev2 == NULL || > > > > > strcmp(cdev1, cdev2) == 0) { > > > > > cdev = (char *)cdev1; > > > > > > > > Ouch, the code is really buggy there. We must fix it instead of > > > > leaving FIXME. > > > > > > > > I see there are multiple bugs (in addition to your patch#1): > > > > > > > > - the error check is wrong, it should be compared with -ENOENT > > > > if (err < 0 && err != ENOENT) > > > > > > > > This leaves cdev1 or cdev2 NULL as non-error. > > > > > > > > - The intention of the code should be (as far as I understand): > > > > - if only one of cdev1 and cdev2 is defined, take it as cdev > > > > - if cdev1 and cdev2 are defined and have the same string, keep > > > > cdev1 and free cdev2 > > > > - in the rest cases, free both cdev1 and cdev2 without changing cdev > > > > > > Regarding that last case, just leaving cdev unchanged is not a good > > > idea. cdev will always be NULL if we don't set it here, and when we call > > > open_ctl(), it must be non-NULL. > > > > Right. I *guess* if cdev1 != cdev2, it should bail out as an error. > > Ok, I'll make a patch that will implement the described behaviour. > It may also be worth adding a comment describing the cdev1/2 usage or maybe even rename them to make it obvious ? Thanks Liam