>>> On 07.07.16 at 12:55, <paul.durr...@citrix.com> wrote: >> -----Original Message----- >> From: netdev-ow...@vger.kernel.org [mailto:netdev- >> ow...@vger.kernel.org] On Behalf Of David Vrabel >> Sent: 07 July 2016 11:45 >> To: Wei Liu; David Vrabel >> Cc: xen-de...@lists.xenproject.org; Jan Beulich; netdev@vger.kernel.org >> Subject: Re: [Xen-devel] [PATCH] xen-netback: correct return value checks >> on xenbus_scanf() >> >> On 07/07/16 11:35, Wei Liu wrote: >> > On Thu, Jul 07, 2016 at 10:58:16AM +0100, David Vrabel wrote: >> >> On 07/07/16 08:57, Jan Beulich wrote: >> >>> Only a positive return value indicates success. >> >> >> >> This is not correct. >> >> >> > >> > Do you mean the commit message is not correct or the code is not >> > correct? If it is the formal, do you have any suggestion to fix it? >> >> This code is correct as-is, thus the commit message is wrong or misleading. > > Is that true? Jan is correct in saying that only >0 is an indicator of > success according to the usual semantics of sccanf().
As was correctly pointed out, xenbus_scanf(), other than scanf(), can't return zero right now (which I think has corner cases where this might be a problem). So if I would get the feeling that a correction (benign or not at this point in time) would be accepted, what about "Only a positive return value is guaranteed to indicates success" as commit description? > Personally I think the > code would be clearer if the checks for failure were < 1 rather than <= 0. I'd be fine with that, albeit if comparing with any non-zero number then I think it would better be == or != instead of < or <=. Jan
