linux-kernel - Re: [PATCH v4 2/2] mm/gup.c: Refactor check_and_migrate_movable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 17 Aug 2022 19:50:06 -0300
From:   Jason Gunthorpe <jgg@...dia.com>
To:     John Hubbard <jhubbard@...dia.com>
Cc:     Alistair Popple <apopple@...dia.com>, linux-mm@...ck.org,
        akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
        "Sierra Guiza, Alejandro (Alex)" <alex.sierra@....com>,
        Chaitanya Kulkarni <kch@...dia.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Felix Kuehling <Felix.Kuehling@....com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Muchun Song <songmuchun@...edance.com>,
        Ralph Campbell <rcampbell@...dia.com>,
        David Hildenbrand <david@...hat.com>,
        Matthew Wilcox <willy@...radead.org>
Subject: Re: [PATCH v4 2/2] mm/gup.c: Refactor
 check_and_migrate_movable_pages()

On Wed, Aug 17, 2022 at 01:35:12PM -0700, John Hubbard wrote:
> How's this look to you:
> 
> 	collected = collect_longterm_unpinnable_pages(&movable_page_list,
> 						      nr_pages, pages);
> 	if (collected == 0)
> 		return 0;
> 
> 	ret = migrate_longterm_unpinnable_pages(&movable_page_list, nr_pages,
> 						pages);
> 
> 	/* If we got here, we have some unpinnable pages... */
> 
> 	if (ret == 0) {
> 		/*
> 		 * ...and we successfully migrated those pages. Which means that
> 		 * the caller should retry the operation now.
> 		 */
> 		ret = -EAGAIN;

return -EAGAIN

> 	}
> 
> 	return ret;

But why return 0 from the helper function in the first place?

Jason