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dkim=pass header.d=Nvidia.com header.s=selector2 header.b=cvS7GVZn; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf11.hostedemail.com: domain of jgg@nvidia.com designates 40.107.94.88 as permitted sender) smtp.mailfrom=jgg@nvidia.com X-Stat-Signature: 1dud1umkmheisj6fz3iuw1prmw7o7mf4 X-HE-Tag: 1660649353-255203 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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