On Thu, Aug 21, 2014 at 11:49:12PM -0700, Andrew Morton wrote: > > > > > > But it's a bit hacky. Can anyone think of anything smarter? > > > > Looks good to me and not that hacky actually. > > Hacky :( I guess it's pretty safe because this is a userspace-visible > structure so we'll never be changing it.
Well, I saw something similar in netfilter code a long ago :) > > Or will we? What happens if we later decide that some additional field > needs to be added? Do we version the interface? Add a new prctl() > mode? Let's cook up a plan for that and at least add to changelog? I don't expect to change it anytime soon but we still have an option -- if we decide to extend or shrink it we always can use sizeof/offsetof helpers to check which exactly version userspace asks us to use. As far as I understand the mm_struct is not the structure which changes that frequently, right? > > Should I update on top for -mm tree? > > Spose so. Let's see what the code savings are when the other two sites > are similarly changed? > > To save a bit more space offsets[] could be an array of uchar, I guess. > A BUILD_BUG_ON(sizeof(struct prctl_map) >= 256) would keep that sane. Sure, thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
