Messages in this thread | | | Date | Tue, 16 Aug 2022 08:29:09 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v4 2/2] mm/gup.c: Refactor check_and_migrate_movable_pages() |
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On Tue, Aug 16, 2022 at 03:29:20PM +1000, Alistair Popple wrote:
> >> +static long check_and_migrate_movable_pages(unsigned long nr_pages, > >> + struct page **pages) > >> +{ > >> + int ret; > >> + unsigned long collected; > >> + LIST_HEAD(movable_page_list); > >> + > >> + collected = collect_longterm_unpinnable_pages(&movable_page_list, nr_pages, pages); > >> + if (!collected) > >> + return 0; > >> + > >> + ret = migrate_longterm_unpinnable_pages(&movable_page_list, nr_pages, pages); > >> + if (!ret) > >> + return -EAGAIN; > >> + else > >> + return ret; > > > > I would drop the else path and just return zero > > Unless I've misunderstood you I don't think that's correct though. > check_and_migrate_movable_pages() needs to return one of 3 conditions: > > - 0: All pages are in the correct zone and are still pinned (ie. "success"). > - -EAGAIN: Some pages were migrated, all pages need re-pinning. > - errno: Migration failed, pins were dropped and PUP should fail. > > John's suggested comment update spells this out more clearly.
But that is not what it does..
if (!ret) == if (ret != 0) return -EAGAIN thus ret == 0 return ret == return 0
Jason
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