Messages in this thread | | | Date | Fri, 21 Nov 2014 16:46:17 +0100 | From | David Sterba <> | Subject | Re: [PATCH v2] Btrfs: qgroup: add BUILD_BUG to report pointer cast breakage |
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On Thu, Nov 13, 2014 at 12:54:39AM +0900, Daniel Dressler wrote: > Our ulist data structure stores at max 64bit > values. qgroup has used this structure to store > pointers. In the future when we upgrade to 128bit > this casting of pointers to uint64_t will break.
What are we going to upgrade to 128 bits?
> This patch adds a BUILD_BUG ensuring that this > code will not be left untouched in the upgrade. > > It also marks this issue on the TODO list so it > may be addressed before such an upgrade. > > + (BUILD_BUG_ON_ZERO(sizeof(uintptr_t) > sizeof(u64)) + \
So it's pointers, this is similar to the 32bit -> 64bit transition, a change that will affect everything, one BUILD_BUG on does not make any difference.
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