From: Oleksandr Andrushchenko <andr2000@gmail.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org, airlied@linux.ie,
daniel.vetter@intel.com, seanpaul@chromium.org,
gustavo@padovan.org, jgross@suse.com, konrad.wilk@oracle.com
Cc: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Subject: Re: [PATCH 5/9] drm/xen-front: Implement handling of shared display buffers
Date: Fri, 23 Feb 2018 16:45:23 +0200 [thread overview]
Message-ID: <bc441999-ec06-794e-99cb-20091c87ede2@gmail.com> (raw)
In-Reply-To: <36003bb4-6fc9-f8f9-2817-103bf0f543e9@oracle.com>
On 02/23/2018 04:36 PM, Boris Ostrovsky wrote:
> On 02/23/2018 02:53 AM, Oleksandr Andrushchenko wrote:
>> On 02/23/2018 02:25 AM, Boris Ostrovsky wrote:
>>> On 02/21/2018 03:03 AM, Oleksandr Andrushchenko wrote:
>>>> static int __init xen_drv_init(void)
>>>> {
>>>> + /* At the moment we only support case with XEN_PAGE_SIZE ==
>>>> PAGE_SIZE */
>>>> + BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
>>> Why BUILD_BUG_ON? This should simply not load if page sizes are
>>> different.
>>>
>>>
>> This is a compile time check, so if kernel/Xen is configured
>> to use page size combination which is not supported by the
>> driver it will fail during compilation. This seems correct to me,
>> because you shouldn't even try to load the driver which
>> cannot handle different page sizes to not make any harm.
>
> This will prevent whole kernel from building. So, for example,
> randconfig builds will fail.
>
makes a lot of sense, thank you
will rework so I reject to load if the requirement is not met
>>>
>>>
>>>> + ret = gnttab_map_refs(map_ops, NULL, buf->pages, buf->num_pages);
>>>> + BUG_ON(ret);
>>> We should try not to BUG*(). There are a few in this patch (and possibly
>>> others) that I think can be avoided.
>>>
>> I will rework BUG_* for map/unmap code to handle errors,
>> but will still leave
>> /* either pages or sgt, not both */
>> BUG_ON(cfg->pages && cfg->sgt);
>> which is a real driver bug and must not happen
> Why not return an error?
>
> In fact, AFAICS you only call it in patch 9 where both of these can be
> tested, in which case something like -EINVAL would look reasonable.
ok, will remove BUG_ON as well
> -boris
next prev parent reply other threads:[~2018-02-23 14:45 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-21 8:03 [PATCH 0/9] drm/xen-front: Add support for Xen PV display frontend Oleksandr Andrushchenko
2018-02-21 8:03 ` [PATCH 1/9] drm/xen-front: Introduce Xen para-virtualized frontend driver Oleksandr Andrushchenko
2018-02-21 8:19 ` Juergen Gross
2018-02-21 8:47 ` Oleksandr Andrushchenko
2018-02-21 9:09 ` Juergen Gross
2018-02-21 9:11 ` Oleksandr Andrushchenko
2018-02-21 9:17 ` [Xen-devel] " Roger Pau Monné
2018-02-21 9:42 ` Oleksandr Andrushchenko
2018-02-21 10:19 ` Roger Pau Monné
2018-02-21 10:25 ` Oleksandr Andrushchenko
2018-02-22 22:23 ` Boris Ostrovsky
2018-02-23 6:37 ` Oleksandr Andrushchenko
2018-02-23 14:39 ` Boris Ostrovsky
2018-02-23 14:51 ` Oleksandr Andrushchenko
2018-02-21 8:03 ` [PATCH 2/9] drm/xen-front: Implement Xen bus state handling Oleksandr Andrushchenko
2018-02-21 8:23 ` Juergen Gross
2018-02-21 8:50 ` Oleksandr Andrushchenko
2018-02-21 8:03 ` [PATCH 3/9] drm/xen-front: Read driver configuration from Xen store Oleksandr Andrushchenko
2018-02-22 23:20 ` Boris Ostrovsky
2018-02-23 6:46 ` Oleksandr Andrushchenko
2018-02-21 8:03 ` [PATCH 4/9] drm/xen-front: Implement Xen event channel handling Oleksandr Andrushchenko
2018-02-22 23:50 ` Boris Ostrovsky
2018-02-23 7:00 ` Oleksandr Andrushchenko
2018-02-23 14:44 ` Boris Ostrovsky
2018-02-23 14:49 ` Oleksandr Andrushchenko
2018-02-21 8:03 ` [PATCH 5/9] drm/xen-front: Implement handling of shared display buffers Oleksandr Andrushchenko
2018-02-23 0:25 ` Boris Ostrovsky
2018-02-23 7:53 ` Oleksandr Andrushchenko
2018-02-23 14:36 ` Boris Ostrovsky
2018-02-23 14:45 ` Oleksandr Andrushchenko [this message]
2018-02-21 8:03 ` [PATCH 6/9] drm/xen-front: Introduce DRM/KMS virtual display driver Oleksandr Andrushchenko
2018-02-23 15:12 ` Boris Ostrovsky
2018-02-23 15:19 ` Oleksandr Andrushchenko
2018-03-05 9:13 ` Daniel Vetter
2018-03-05 9:19 ` Oleksandr Andrushchenko
2018-02-21 8:03 ` [PATCH 7/9] drm/xen-front: Implement KMS/connector handling Oleksandr Andrushchenko
2018-03-05 9:23 ` Daniel Vetter
2018-03-05 12:59 ` Oleksandr Andrushchenko
2018-03-06 7:22 ` Daniel Vetter
2018-03-06 7:29 ` Oleksandr Andrushchenko
2018-02-21 8:03 ` [PATCH 8/9] drm/xen-front: Implement GEM operations Oleksandr Andrushchenko
2018-02-23 15:26 ` Boris Ostrovsky
2018-02-23 15:35 ` Oleksandr Andrushchenko
2018-02-26 23:47 ` Boris Ostrovsky
2018-02-27 6:52 ` Oleksandr Andrushchenko
2018-02-28 19:46 ` Boris Ostrovsky
2018-02-28 19:52 ` Oleksandr Andrushchenko
2018-03-05 9:32 ` Daniel Vetter
2018-03-05 13:46 ` Oleksandr Andrushchenko
2018-03-06 7:26 ` Daniel Vetter
2018-03-06 7:43 ` Oleksandr Andrushchenko
2018-02-21 8:03 ` [PATCH 9/9] drm/xen-front: Implement communication with backend Oleksandr Andrushchenko
2018-03-05 9:25 ` Daniel Vetter
2018-03-05 9:30 ` Oleksandr Andrushchenko
2018-03-06 9:26 ` Daniel Vetter
2018-03-06 9:45 ` Oleksandr Andrushchenko
2018-02-26 8:21 ` [PATCH 0/9] drm/xen-front: Add support for Xen PV display frontend Oleksandr Andrushchenko
2018-02-27 12:40 ` Oleksandr Andrushchenko
2018-02-28 14:08 ` [Xen-devel] " Julien Grall
2018-03-01 1:42 ` Stefano Stabellini
2018-03-01 8:26 ` Gerd Hoffmann
2018-03-01 8:49 ` Oleksandr Andrushchenko
2018-03-01 1:14 ` Stefano Stabellini
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