linux-kernel - Re: [PATCH 3/6] drm/i915: use vmap in shmem_pin

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: <20200922143906.GB26664@lst.de>
Date:   Tue, 22 Sep 2020 16:39:06 +0200
From:   Christoph Hellwig <hch@....de>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     Christoph Hellwig <hch@....de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Minchan Kim <minchan@...nel.org>,
        Nitin Gupta <ngupta@...are.org>, x86@...nel.org,
        xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-mm@...ck.org
Subject: Re: [PATCH 3/6] drm/i915: use vmap in shmem_pin_map

On Tue, Sep 22, 2020 at 12:21:44PM +0100, Matthew Wilcox wrote:
> Actually, vfree() will work today; I cc'd you on a documentation update
> to make it clear that this is permitted.

vfree calls __free_pages, the i915 and a lot of other code calls
put_page.  They are mostly the same, but not quite and everytime I
look into that mess I'm more confused than before.

Can someone in the know write sensible documentation on when to use
__free_page(s) vs put_page?