Hi Kevin, Thanks for looking to this. > Hmm. I hadn't noticed that the other drivers are returning a static > structure. In that case, it seems that report_fixup itself is broken > from a memory perspective, in that it returns pointers to > inconsistent storage types depending on the driver. The driver can either modify the existing buffer, of return a pointer to a buffer managed by the driver. The former requires a kmemdup before, the latter a kmemdup after. > 1. Ugly workaround: make a temporary copy of the dev_rdesc, give it > to report_fixup, make a copy of the return, store that copy in > rdesc, free the temporary copy. Though ugly, this would at least > involve the smallest diff. Yes, it is correct and ugly, in no particular order. > 2. Standardize the behavior of the drivers' report_fixup > implementations. Given that some of them need to change the size of > the descriptor, modifying the passed structure is not an option. > Probably all of them should return a newly allocated structure, > either a modified copy of the input or a copy of their static, that > can then be stored directly in rdesc. Especially since report_fixup > is only ever called right before a copy is going to be taken anyway. Relying on the returned pointer to be properly alloc'd is not a good idea, in particular since it changes semantics rather drastically. Since the current function performs two different things, perhaps there should be two different functions instead. > (Adding constness to a parameter isn't considered a severe ABI > break, is it?) Inside the kernel there is no ABI. Go wild. Thanks, Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
