linux-kernel - Re: [PATCH 02/12] buffer: grow_dev_page() should use __GFP

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: <20171003122559.GL11879@quack2.suse.cz>
Date:   Tue, 3 Oct 2017 14:25:59 +0200
From:   Jan Kara <jack@...e.cz>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        hannes@...xchg.org, jack@...e.cz, torvalds@...ux-foundation.org
Subject: Re: [PATCH 02/12] buffer: grow_dev_page() should use __GFP_NOFAIL
 for all cases

On Tue 03-10-17 14:10:49, Jan Kara wrote:
> On Wed 27-09-17 14:13:49, Jens Axboe wrote:
> > We currently it it for find_or_create_page(), which means that it
> > cannot fail. Ensure we also pass in 'retry == true' to
> > alloc_page_buffers(), which also ensure that it cannot fail.
> > 
> > After this, there are no failure cases in grow_dev_page() that
> > occur because of a failed memory allocation.
> > 
> > Signed-off-by: Jens Axboe <axboe@...nel.dk>
> 
> Makes sense. You can add:
> 
> Reviewed-by: Jan Kara <jack@...e.cz>

I forgot one question though:

> >  	page = find_or_create_page(inode->i_mapping, index, gfp_mask);
> > -	if (!page)
> > -		return ret;

Are we sure find_or_create_page() cannot fail for other reasons than
ENOMEM? Currently it seems to be the case AFAICT but it isn't obvious to me
that is guaranteed in future as well...

								Honza

-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR