Re: [PATCH 06/11] drm/syncobj: add timeline payload query ioctl v4

[zhoucm1 <zhoucm1-5C7GfCeVMHo@public.gmane.org>]

On 2019年02月17日 03:22, Christian König wrote:
> Am 15.02.19 um 20:31 schrieb Lionel Landwerlin via amd-gfx:
>> On 07/12/2018 09:55, Chunming Zhou wrote:
>>> user mode can query timeline payload.
>>> v2: check return value of copy_to_user
>>> v3: handle querying entry by entry
>>> v4: rebase on new chain container, simplify interface
>>>
>>> Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
>>> Cc: Daniel Rakos <Daniel.Rakos@amd.com>
>>> Cc: Jason Ekstrand <jason@jlekstrand.net>
>>> Cc: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
>>> Cc: Dave Airlie <airlied@redhat.com>
>>> Cc: Christian König <christian.koenig@amd.com>
>>> Cc: Chris Wilson <chris@chris-wilson.co.uk>
>>> ---
>>>   drivers/gpu/drm/drm_internal.h |  2 ++
>>>   drivers/gpu/drm/drm_ioctl.c    |  2 ++
>>>   drivers/gpu/drm/drm_syncobj.c  | 43 
>>> ++++++++++++++++++++++++++++++++++
>>>   include/uapi/drm/drm.h         | 10 ++++++++
>>>   4 files changed, 57 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/drm_internal.h 
>>> b/drivers/gpu/drm/drm_internal.h
>>> index 18b41e10195c..dab4d5936441 100644
>>> --- a/drivers/gpu/drm/drm_internal.h
>>> +++ b/drivers/gpu/drm/drm_internal.h
>>> @@ -184,6 +184,8 @@ int drm_syncobj_reset_ioctl(struct drm_device 
>>> *dev, void *data,
>>>                   struct drm_file *file_private);
>>>   int drm_syncobj_signal_ioctl(struct drm_device *dev, void *data,
>>>                    struct drm_file *file_private);
>>> +int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
>>> +                struct drm_file *file_private);
>>>     /* drm_framebuffer.c */
>>>   void drm_framebuffer_print_info(struct drm_printer *p, unsigned 
>>> int indent,
>>> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
>>> index a9a17ed35cc4..7578ef6dc1d1 100644
>>> --- a/drivers/gpu/drm/drm_ioctl.c
>>> +++ b/drivers/gpu/drm/drm_ioctl.c
>>> @@ -681,6 +681,8 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
>>>                 DRM_UNLOCKED|DRM_RENDER_ALLOW),
>>>       DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_SIGNAL, drm_syncobj_signal_ioctl,
>>>                 DRM_UNLOCKED|DRM_RENDER_ALLOW),
>>> +    DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_QUERY, drm_syncobj_query_ioctl,
>>> +              DRM_UNLOCKED|DRM_RENDER_ALLOW),
>>>       DRM_IOCTL_DEF(DRM_IOCTL_CRTC_GET_SEQUENCE, 
>>> drm_crtc_get_sequence_ioctl, DRM_UNLOCKED),
>>>       DRM_IOCTL_DEF(DRM_IOCTL_CRTC_QUEUE_SEQUENCE, 
>>> drm_crtc_queue_sequence_ioctl, DRM_UNLOCKED),
>>>       DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_LEASE, 
>>> drm_mode_create_lease_ioctl, DRM_MASTER|DRM_UNLOCKED),
>>> diff --git a/drivers/gpu/drm/drm_syncobj.c 
>>> b/drivers/gpu/drm/drm_syncobj.c
>>> index 348079bb0965..f97fa00ca1d0 100644
>>> --- a/drivers/gpu/drm/drm_syncobj.c
>>> +++ b/drivers/gpu/drm/drm_syncobj.c
>>> @@ -1061,3 +1061,46 @@ drm_syncobj_signal_ioctl(struct drm_device 
>>> *dev, void *data,
>>>         return ret;
>>>   }
>>> +
>>> +int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
>>> +                struct drm_file *file_private)
>>> +{
>>> +    struct drm_syncobj_timeline_array *args = data;
>>> +    struct drm_syncobj **syncobjs;
>>> +    uint64_t __user *points = u64_to_user_ptr(args->points);
>>> +    uint32_t i;
>>> +    int ret;
>>> +
>>> +    if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
>>> +        return -ENODEV;
>>> +
>>> +    if (args->pad != 0)
>>> +        return -EINVAL;
>>> +
>>> +    if (args->count_handles == 0)
>>> +        return -EINVAL;
>>> +
>>> +    ret = drm_syncobj_array_find(file_private,
>>> +                     u64_to_user_ptr(args->handles),
>>> +                     args->count_handles,
>>> +                     &syncobjs);
>>> +    if (ret < 0)
>>> +        return ret;
>>> +
>>> +    for (i = 0; i < args->count_handles; i++) {
>>> +        struct dma_fence_chain *chain;
>>> +        struct dma_fence *fence;
>>> +        uint64_t point;
>>> +
>>> +        fence = drm_syncobj_fence_get(syncobjs[i]);
>>> +        chain = to_dma_fence_chain(fence);
>>> +        point = chain ? fence->seqno : 0;
>>
>>
>> Sorry, I don' t want to sound annoying, but this looks like this 
>> could report values going backward.
>
> Well please be annoying as much as you can :) But yeah all that stuff 
> has been discussed before as well.
>
>>
>> Anything add a point X to a timeline that has reached value Y with X 
>> < Y would trigger that.
>
> Yes, that can indeed happen.
trigger what? when adding x (x < y), then return 0 when query?
Why would this happen?
No, syncobj->fence should always be there and the last chain node, if it 
is ever added.

-David
> But adding a timeline point X which is before the already added point 
> Y is illegal in the first place :)
>
> So when the application does something stupid and breaks it can just 
> keep the pieces.
>
> In the kernel we still do the most defensive thing and sync to 
> everything in this case.
>
> I'm just not sure if we should print an error into syslog or just 
> continue silently.
>
> Regards,
> Christian.
>
>>
>> Either through the submission or userspace signaling or importing 
>> another syncpoint's fence.
>>
>>
>> -Lionel
>>
>>
>>> +        ret = copy_to_user(&points[i], &point, sizeof(uint64_t));
>>> +        ret = ret ? -EFAULT : 0;
>>> +        if (ret)
>>> +            break;
>>> +    }
>>> +    drm_syncobj_array_free(syncobjs, args->count_handles);
>>> +
>>> +    return ret;
>>> +}
>>> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
>>> index 0092111d002c..b2c36f2b2599 100644
>>> --- a/include/uapi/drm/drm.h
>>> +++ b/include/uapi/drm/drm.h
>>> @@ -767,6 +767,14 @@ struct drm_syncobj_array {
>>>       __u32 pad;
>>>   };
>>>   +struct drm_syncobj_timeline_array {
>>> +    __u64 handles;
>>> +    __u64 points;
>>> +    __u32 count_handles;
>>> +    __u32 pad;
>>> +};
>>> +
>>> +
>>>   /* Query current scanout sequence number */
>>>   struct drm_crtc_get_sequence {
>>>       __u32 crtc_id;        /* requested crtc_id */
>>> @@ -924,6 +932,8 @@ extern "C" {
>>>   #define DRM_IOCTL_MODE_REVOKE_LEASE    DRM_IOWR(0xC9, struct 
>>> drm_mode_revoke_lease)
>>>     #define DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT    DRM_IOWR(0xCA, struct 
>>> drm_syncobj_timeline_wait)
>>> +#define DRM_IOCTL_SYNCOBJ_QUERY        DRM_IOWR(0xCB, struct 
>>> drm_syncobj_timeline_array)
>>> +
>>>   /**
>>>    * Device specific ioctls should only be in their respective headers
>>>    * The device specific ioctl range is from 0x40 to 0x9f.
>>
>>
>> _______________________________________________
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>> amd-gfx@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>

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