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 -- 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
