linux-kernel - Re: [PATCH v20 29/32] block: Replace BIO_NO_PAGE_REF with BIO_PAGE

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]

Message-ID: <ZGhI/V573cMDhII5@moria.home.lan>
Date:   Sat, 20 May 2023 00:13:49 -0400
From:   Kent Overstreet <kent.overstreet@...ux.dev>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     David Howells <dhowells@...hat.com>, Jens Axboe <axboe@...nel.dk>,
        Al Viro <viro@...iv.linux.org.uk>,
        Matthew Wilcox <willy@...radead.org>, Jan Kara <jack@...e.cz>,
        Jeff Layton <jlayton@...nel.org>,
        David Hildenbrand <david@...hat.com>,
        Jason Gunthorpe <jgg@...dia.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Hillf Danton <hdanton@...a.com>,
        Christian Brauner <brauner@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Christoph Hellwig <hch@....de>,
        John Hubbard <jhubbard@...dia.com>
Subject: Re: [PATCH v20 29/32] block: Replace BIO_NO_PAGE_REF with
 BIO_PAGE_REFFED with inverted logic

On Fri, May 19, 2023 at 08:56:56PM -0700, Christoph Hellwig wrote:
> On Fri, May 19, 2023 at 09:26:07PM -0400, Kent Overstreet wrote:
> > On Fri, May 19, 2023 at 08:40:44AM +0100, David Howells wrote:
> > > From: Christoph Hellwig <hch@....de>
> > > 
> > > Replace BIO_NO_PAGE_REF with a BIO_PAGE_REFFED flag that has the inverted
> > > meaning is only set when a page reference has been acquired that needs to
> > > be released by bio_release_pages().
> > 
> > What was the motivation for this patch?
> 
> So that is only is set when we need to release a page, instead telling
> code to not release it when it otherwise would, where otherwise would
> is implicit and undocumented and changes in this series.

I suppose this way setting it can be done in bio_iov_iter_get_pages() -
ok yeah, that makes sense.

But it seems like it should be set in bio_iov_iter_get_pages() though,
and I'm not seeing that?