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From: Ilija Hadzic <ihadzic@research.bell-labs.com>
To: Dave Airlie <airlied@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 05/19] drm: move dev_mapping to the minor node
Date: Tue, 15 May 2012 15:48:13 -0500 (CDT)	[thread overview]
Message-ID: <Pine.GSO.4.64.1205151542150.7814@umail> (raw)
In-Reply-To: <CAPM=9twaEpiXSY_Dd7jLcNC6q6v9vBJhFnN-Q4AD2cbMggFaPg@mail.gmail.com>



On Mon, 30 Apr 2012, Dave Airlie wrote:

> On Mon, Apr 30, 2012 at 6:53 PM, Dave Airlie <airlied@gmail.com> wrote:
>>>
>>> Do you have pointers to that discussion (assuming it was on sime mailing
>>> list)? The least I can do, while I am at it, is try to understand it and
>>> see if I can incorporate some ideas from there in the rework of the patch.
>>
>> Nope it was an offhand discussion on irc while we were talking about
>> some other ugly code.
>
> Okay I think it was the code in coda,
>
>       if (coda_inode->i_mapping == &coda_inode->i_data)
>                coda_inode->i_mapping = host_inode->i_mapping;
>
>        /* only allow additional mmaps as long as userspace isn't changing
>         * the container file on us! */
>        else if (coda_inode->i_mapping != host_inode->i_mapping) {
>                spin_unlock(&cii->c_lock);
>                return -EBUSY;
>        }
>
> We could use code like that to change the i_mapping, instead of failing.
>
> Dave.
>

I have just cut (and sent to the list) a patch that, I believe, implements 
this idea. I did it slightly differently from what coda fs does, but it's 
the same concept. I set i_mapping in the open() instead of moving it 
down to mmap(), because there are so many variants of mmap both in drm and 
GPU-specific drivers, that it would get too messy.

I traced the code quite extensively with printks and it looks like it's 
doing the right thing.

If the new patch seems right, then if and when we add render nodes, the 
original dev_mapping patch that started this thread won't be needed any 
more.

-- Ilija

  reply	other threads:[~2012-05-15 20:48 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-12 18:19 [RFC v2] Revive the work on render-nodes branch Ilija Hadzic
2012-04-12 18:19 ` [PATCH 01/19] drm: simplify dereferencing of node type Ilija Hadzic
2012-04-12 18:19 ` [PATCH 02/19] drm: track planes in drm_mode_group structure Ilija Hadzic
2012-04-12 18:19 ` [PATCH 03/19] drm: use drm_mode_group in drm_mode_getplane_res Ilija Hadzic
2012-04-12 18:19 ` [PATCH 04/19] drm: do not push inode down into drm_open_helper Ilija Hadzic
2012-04-12 18:19 ` [PATCH 05/19] drm: move dev_mapping to the minor node Ilija Hadzic
2012-04-20 10:04   ` Dave Airlie
2012-04-30 14:48     ` Ilija Hadzic
2012-04-30 16:39       ` Dave Airlie
2012-04-30 16:52         ` Ilija Hadzic
2012-04-30 17:53           ` Dave Airlie
2012-04-30 18:04             ` Dave Airlie
2012-05-15 20:48               ` Ilija Hadzic [this message]
2012-04-12 18:19 ` [PATCH 06/19] drm: add support for render nodes Ilija Hadzic
2012-04-12 18:19 ` [PATCH 07/19] drm: initial multiple nodes ioctl work Ilija Hadzic
2012-04-20 10:15   ` Dave Airlie
2012-04-12 18:19 ` [PATCH 08/19] drm: separate render node descriptor from minor Ilija Hadzic
2012-04-12 18:19 ` [PATCH 09/19] drm: cleanup render node ioctls Ilija Hadzic
2012-04-12 18:19 ` [PATCH 10/19] drm: only allow render node ioctls through control node Ilija Hadzic
2012-04-12 18:19 ` [PATCH 11/19] drm: do not remove a render node in use Ilija Hadzic
2012-04-12 18:19 ` [PATCH 12/19] drm: allocate correct id_list size for a render node Ilija Hadzic
2012-04-12 18:19 ` [PATCH 13/19] drm: add drm_mode_group_fini function Ilija Hadzic
2012-04-12 18:19 ` [PATCH 14/19] drm: properly free id_list when a render node is removed Ilija Hadzic
2012-04-12 18:19 ` [PATCH 15/19] drm: call drm_mode_group_fini on primary node Ilija Hadzic
2012-04-12 18:19 ` [PATCH 16/19] drm: more elaborate check for resource count Ilija Hadzic
2012-04-12 18:19 ` [PATCH 17/19] drm: validate id list when creating a render node Ilija Hadzic
2012-04-12 18:19 ` [PATCH 18/19] drm: keep track of which node holds which resource Ilija Hadzic
2012-04-12 18:19 ` [PATCH 19/19] drm: hold mutex in critical sections of render-node code Ilija Hadzic
2012-04-12 18:55 ` [RFC v2] Revive the work on render-nodes branch Ville Syrjälä
2012-04-12 19:09   ` Ilija Hadzic
2012-04-20 10:20 ` Dave Airlie
2012-04-20 13:46   ` Daniel Vetter
2012-04-30 15:16   ` Ilija Hadzic
2012-04-30 19:01   ` Kristian Høgsberg

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