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
WARNING: multiple messages have this Message-ID (diff)
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 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2018-02-23 14:45 UTC|newest] Thread overview: 165+ 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 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` [PATCH 1/9] drm/xen-front: Introduce Xen para-virtualized frontend driver Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:19 ` Juergen Gross 2018-02-21 8:19 ` Juergen Gross 2018-02-21 8:47 ` Oleksandr Andrushchenko 2018-02-21 8:47 ` Oleksandr Andrushchenko 2018-02-21 8:47 ` Oleksandr Andrushchenko 2018-02-21 9:09 ` Juergen Gross 2018-02-21 9:09 ` Juergen Gross 2018-02-21 9:11 ` Oleksandr Andrushchenko 2018-02-21 9:11 ` Oleksandr Andrushchenko 2018-02-21 9:11 ` Oleksandr Andrushchenko 2018-02-21 9:17 ` [Xen-devel] " Roger Pau Monné 2018-02-21 9:17 ` Roger Pau Monné 2018-02-21 9:42 ` [Xen-devel] " Oleksandr Andrushchenko 2018-02-21 9:42 ` Oleksandr Andrushchenko 2018-02-21 10:19 ` Roger Pau Monné 2018-02-21 10:19 ` Roger Pau Monné 2018-02-21 10:25 ` Oleksandr Andrushchenko 2018-02-21 10:25 ` [Xen-devel] " Oleksandr Andrushchenko 2018-02-21 10:25 ` Oleksandr Andrushchenko 2018-02-21 9:42 ` Oleksandr Andrushchenko 2018-02-22 22:23 ` Boris Ostrovsky 2018-02-22 22:23 ` Boris Ostrovsky 2018-02-23 6:37 ` Oleksandr Andrushchenko 2018-02-23 6:37 ` Oleksandr Andrushchenko 2018-02-23 14:39 ` Boris Ostrovsky 2018-02-23 14:39 ` Boris Ostrovsky 2018-02-23 14:51 ` Oleksandr Andrushchenko 2018-02-23 14:51 ` Oleksandr Andrushchenko 2018-02-23 14:51 ` Oleksandr Andrushchenko 2018-02-23 6:37 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` [PATCH 2/9] drm/xen-front: Implement Xen bus state handling Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:23 ` Juergen Gross 2018-02-21 8:23 ` Juergen Gross 2018-02-21 8:50 ` Oleksandr Andrushchenko 2018-02-21 8:50 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` [PATCH 3/9] drm/xen-front: Read driver configuration from Xen store Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-22 23:20 ` Boris Ostrovsky 2018-02-22 23:20 ` Boris Ostrovsky 2018-02-23 6:46 ` Oleksandr Andrushchenko 2018-02-23 6:46 ` Oleksandr Andrushchenko 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 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-22 23:50 ` Boris Ostrovsky 2018-02-22 23:50 ` Boris Ostrovsky 2018-02-23 7:00 ` Oleksandr Andrushchenko 2018-02-23 7:00 ` Oleksandr Andrushchenko 2018-02-23 7:00 ` Oleksandr Andrushchenko 2018-02-23 14:44 ` Boris Ostrovsky 2018-02-23 14:44 ` Boris Ostrovsky 2018-02-23 14:49 ` Oleksandr Andrushchenko 2018-02-23 14:49 ` Oleksandr Andrushchenko 2018-02-23 14:49 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` [PATCH 5/9] drm/xen-front: Implement handling of shared display buffers Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-23 0:25 ` Boris Ostrovsky 2018-02-23 0:25 ` Boris Ostrovsky 2018-02-23 7:53 ` Oleksandr Andrushchenko 2018-02-23 7:53 ` Oleksandr Andrushchenko 2018-02-23 14:36 ` Boris Ostrovsky 2018-02-23 14:36 ` Boris Ostrovsky 2018-02-23 14:45 ` Oleksandr Andrushchenko 2018-02-23 14:45 ` Oleksandr Andrushchenko [this message] 2018-02-23 14:45 ` Oleksandr Andrushchenko 2018-02-23 7:53 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` [PATCH 6/9] drm/xen-front: Introduce DRM/KMS virtual display driver Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-23 15:12 ` Boris Ostrovsky 2018-02-23 15:12 ` Boris Ostrovsky 2018-02-23 15:19 ` Oleksandr Andrushchenko 2018-02-23 15:19 ` Oleksandr Andrushchenko 2018-02-23 15:19 ` Oleksandr Andrushchenko 2018-03-05 9:13 ` Daniel Vetter 2018-03-05 9:13 ` Daniel Vetter 2018-03-05 9:19 ` Oleksandr Andrushchenko 2018-03-05 9:19 ` Oleksandr Andrushchenko 2018-03-05 9:19 ` Oleksandr Andrushchenko 2018-03-05 9:13 ` Daniel Vetter 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` [PATCH 7/9] drm/xen-front: Implement KMS/connector handling Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-03-05 9:23 ` Daniel Vetter 2018-03-05 9:23 ` Daniel Vetter 2018-03-05 12:59 ` Oleksandr Andrushchenko 2018-03-05 12:59 ` Oleksandr Andrushchenko 2018-03-06 7:22 ` Daniel Vetter 2018-03-06 7:22 ` Daniel Vetter 2018-03-06 7:22 ` Daniel Vetter 2018-03-06 7:29 ` Oleksandr Andrushchenko 2018-03-06 7:29 ` Oleksandr Andrushchenko 2018-03-06 7:29 ` Oleksandr Andrushchenko 2018-03-05 12:59 ` Oleksandr Andrushchenko 2018-03-05 9:23 ` Daniel Vetter 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` [PATCH 8/9] drm/xen-front: Implement GEM operations Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-23 15:26 ` Boris Ostrovsky 2018-02-23 15:26 ` Boris Ostrovsky 2018-02-23 15:35 ` Oleksandr Andrushchenko 2018-02-23 15:35 ` Oleksandr Andrushchenko 2018-02-26 23:47 ` Boris Ostrovsky 2018-02-27 6:52 ` Oleksandr Andrushchenko 2018-02-27 6:52 ` Oleksandr Andrushchenko 2018-02-27 6:52 ` Oleksandr Andrushchenko 2018-02-28 19:46 ` Boris Ostrovsky 2018-02-28 19:46 ` Boris Ostrovsky 2018-02-28 19:52 ` Oleksandr Andrushchenko 2018-02-28 19:52 ` Oleksandr Andrushchenko 2018-02-28 19:52 ` Oleksandr Andrushchenko 2018-02-26 23:47 ` Boris Ostrovsky 2018-03-05 9:32 ` Daniel Vetter 2018-03-05 9:32 ` Daniel Vetter 2018-03-05 9:32 ` Daniel Vetter 2018-03-05 13:46 ` Oleksandr Andrushchenko 2018-03-05 13:46 ` Oleksandr Andrushchenko 2018-03-05 13:46 ` Oleksandr Andrushchenko 2018-03-06 7:26 ` Daniel Vetter 2018-03-06 7:43 ` Oleksandr Andrushchenko 2018-03-06 7:43 ` Oleksandr Andrushchenko 2018-03-06 7:26 ` Daniel Vetter 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-21 8:03 ` [PATCH 9/9] drm/xen-front: Implement communication with backend Oleksandr Andrushchenko 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-03-05 9:25 ` Daniel Vetter 2018-03-05 9:25 ` Daniel Vetter 2018-03-05 9:25 ` Daniel Vetter 2018-03-05 9:30 ` Oleksandr Andrushchenko 2018-03-05 9:30 ` Oleksandr Andrushchenko 2018-03-06 9:26 ` Daniel Vetter 2018-03-06 9:26 ` Daniel Vetter 2018-03-06 9:45 ` Oleksandr Andrushchenko 2018-03-06 9:45 ` Oleksandr Andrushchenko 2018-03-06 9:26 ` Daniel Vetter 2018-02-21 8:03 ` Oleksandr Andrushchenko 2018-02-26 8:21 ` [PATCH 0/9] drm/xen-front: Add support for Xen PV display frontend Oleksandr Andrushchenko 2018-02-26 8:21 ` Oleksandr Andrushchenko 2018-02-27 12:40 ` Oleksandr Andrushchenko 2018-02-27 12:40 ` 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 1:42 ` [Xen-devel] " Stefano Stabellini 2018-03-01 1:42 ` Stefano Stabellini 2018-02-28 14:08 ` Julien Grall 2018-03-01 8:26 ` Gerd Hoffmann 2018-03-01 8:26 ` Gerd Hoffmann 2018-03-01 8:26 ` Gerd Hoffmann 2018-03-01 8:49 ` Oleksandr Andrushchenko 2018-03-01 8:49 ` Oleksandr Andrushchenko 2018-03-01 8:49 ` Oleksandr Andrushchenko 2018-02-26 8:21 ` Oleksandr Andrushchenko 2018-03-01 1:14 ` Stefano Stabellini 2018-03-01 1:14 ` Stefano Stabellini 2018-03-01 1:14 ` Stefano Stabellini
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