On 2 July 2015 at 15:32, nick <xerofoify@xxxxxxxxx> wrote: > > > On 2015-06-24 03:16 AM, Arnd Bergmann wrote: >> On Tuesday 23 June 2015 17:54:33 Joe Perches wrote: >>> On Tue, 2015-06-23 at 20:44 -0400, nick wrote: >>>> On 2015-06-23 08:40 PM, Joe Perches wrote: >>>>> On Wed, 2015-06-24 at 00:24 +0000, Kuninori Morimoto wrote: >>>>>>>> >>>>>>>> It's far more common (~10:1) in the kernel to cast using >>>>>>>> (<type> *)(unsigned long)<foo> >>>>>>>> than >>>>>>>> (<type> *)(uintptr_t)<foo> >>>>>>>> >>>>>>> Joe, >>>>>>> I agree it's more common in the kernel but one of the maintainers when I sent >>>>>>> this patch a month ago requested I use uintpr_t instead of unsigned long for >>>>>>> the casting. Otherwise I would have done the cast to fix the build warning >>>>>>> with unsigned long instead. >>>>>> >>>>>> This mail >>>>>> http://thread.gmane.org/gmane.linux.kernel.mmc/32304 >>>>> >>>>> uintptr_t was introduced to avoid ptrdiff_t misuse in >>>>> commit 142956af5250 ("fix abuses of ptrdiff_t") by Al Viro. >>>>> >>>>> unsigned long is preponderant, long is used about 1/4 as >>>>> often as unsigned long, uintptr_t is relatively uncommon. >>>>> >>>>> If someone wants to go and convert the 800 or so casts to >>>>> long or unsigned long to uintptr_t so that's the style most >>>>> frequently used, that'd be different. I'm not going to >>>>> submit any patches for that. >>>>> >>>>> >>>> I am not disagreeing it was just easier to listen to the maintainer rather >>>> then get in a technical argument over which type is better for the cast. >>> >>> Laurent has authored a couple patches to that file and he gave >>> you his opinion about using uintptr_t. >>> >>> I'm giving an opinion too, just with a little statistics. >>> >>> I think it's better to use the style that the kernel generally >>> uses. >>> >>> I'll stop replying now. >> >> Instead of debating the type of cast that is used here, it would be nicer >> to do a patch that avoids the cast in the driver entirely, by changing >> the pdata to contain a void* type from the start, and to pass the >> shdma_chan_filter function pointer along with it from platform code. >> >> That would make the sh_mmcif driver independent of the underlying dma >> driver. >> >> Arnd >> > Arnd, > I would have to agree with you but would like the other people in this discussion to agree > before I rewrite this function and pdata structure to do this. Otherwise this patch will > be the current solution for this. > Cheers, > Nick > P.S. Sorry for the late reply been very busy. Let's follow Arnd's suggestion! Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
