Hi Will, On Thu, Jul 16, 2015 at 11:23:26AM +0100, Will Deacon wrote: > On Thu, Jul 16, 2015 at 09:30:43AM +0100, Joerg Roedel wrote: > > +struct of_phandle_args *of_alloc_phandle_args(int size) > > +{ > > + struct of_phandle_args *args; > > + int e = max(0, size - MAX_PHANDLE_ARGS); > > + > > + args = kzalloc(sizeof(struct of_phandle_args) + e * sizeof(uint32_t), > > + GFP_KERNEL); > > Should you also update args->args_count to reflect the extended array? The args_count member just tells us how many of the array elements are used and not how many there are. So it doesn't need to be updated here. > That said, extending the fixed-size array member like this feels a bit > fragile. Does GCC not complain about out-of-bounds accesses if you > statically address args->args[MAX_PHANDLE_ARGS]? Admittedly, I can't > think *why* this would be break (things like additional padding will be > harmless), but I'm not intimate with the C standard. Yeah, I agree, it is not the best possible solution. But this way I don't need to update all callers, and thus it works better with our development model. But I am open for suggestions on how to solve this problem better. In fact, my main motivation in sending this was to get the discussion about an upstreamable solution started :) Lets see what the device-tree maintainers have to say. > I guess the more worrying possibility is if somebody adds a new member to > the end of of_phandle_args. I should probably add a comment there. Joerg -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html