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[106.69.171.132]) by smtp.gmail.com with ESMTPSA id r4sm3968706pjf.4.2020.09.27.05.39.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 27 Sep 2020 05:39:37 -0700 (PDT) Date: Sun, 27 Sep 2020 20:39:32 +0800 From: Kent Gibson To: Andy Shevchenko Cc: Linux Kernel Mailing List , "open list:GPIO SUBSYSTEM" , Bartosz Golaszewski , Linus Walleij , Arnd Bergmann Subject: Re: [PATCH v9 07/20] gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL Message-ID: <20200927123932.GA20442@sol> References: <20200922023151.387447-1-warthog618@gmail.com> <20200922023151.387447-8-warthog618@gmail.com> <20200924080921.GE17562@sol> <20200926091631.GA89482@sol> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Sun, Sep 27, 2020 at 12:00:04PM +0300, Andy Shevchenko wrote: > On Sat, Sep 26, 2020 at 12:16 PM Kent Gibson wrote: > > On Fri, Sep 25, 2020 at 01:06:02PM +0300, Andy Shevchenko wrote: > > ... > > > Hmmm, there is more to it than I thought - gpiod_request_commit(), > > which this code eventually calls, interprets a null label (not an > > empty string) as indicating that the user has not set the label, in > > which case it will set the desc label to "?". So userspace cannot > > force the desc label to be empty. > > > > We need to keep that label as null in that case to maintain that > > behaviour. > > > > I will add a comment there though. > > > > Hmmm, having said that, does this form work for you: > > > > if (ulr.consumer[0] != '\0') { > > /* label is only initialized if consumer is set */ > > lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, GFP_KERNEL); > > ... > > > > It actually compiles slightly larger, I guess due to the extra parameter > > in the kstrndup() call, but may be slightly more readable?? > > I really don't want to delay this series, choose what you think is > better and we may amend it later. > OK, as this code is common with v1 I'll leave it as is - we can always change it for all cases in a later patch. I think that is everything outstanding for v9, so should have a v10 out shortly. Cheers, Kent.