Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> I'm not seeing where we skip the unpin of the zero page, as commented
> in patch 1 (but maybe I'm not reviewing carefully enough as I'm at a
> conference right now).
It's done by unpin_user_page{,s}(), hidden away in gup.c. See the commit
message for patch 1:
Make pin_user_pages*() leave a ZERO_PAGE unpinned if it extracts a
pointer to it from the page tables and make unpin_user_page*()
correspondingly ignore a ZERO_PAGE when unpinning.
David
