Re: [PATCH 8/9] drm/syncobj: add timeline signal ioctl for syncobj v3

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

On 2019年03月19日 19:54, Lionel Landwerlin wrote:
> On 15/03/2019 12:09, Chunming Zhou wrote:
>> v2: individually allocate chain array, since chain node is free 
>> independently.
>> v3: all existing points must be already signaled before cpu perform 
>> signal operation,
>>      so add check condition for that.
>>
>> Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
>> ---
>>   drivers/gpu/drm/drm_internal.h |   2 +
>>   drivers/gpu/drm/drm_ioctl.c    |   2 +
>>   drivers/gpu/drm/drm_syncobj.c  | 103 +++++++++++++++++++++++++++++++++
>>   include/uapi/drm/drm.h         |   1 +
>>   4 files changed, 108 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_internal.h 
>> b/drivers/gpu/drm/drm_internal.h
>> index dd11ae5f1eef..d9a483a5fce0 100644
>> --- a/drivers/gpu/drm/drm_internal.h
>> +++ b/drivers/gpu/drm/drm_internal.h
>> @@ -190,6 +190,8 @@ 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_timeline_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);
>>   diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
>> index 92b3b7b2fd81..d337f161909c 100644
>> --- a/drivers/gpu/drm/drm_ioctl.c
>> +++ b/drivers/gpu/drm/drm_ioctl.c
>> @@ -696,6 +696,8 @@ 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_TIMELINE_SIGNAL, 
>> drm_syncobj_timeline_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),
>> diff --git a/drivers/gpu/drm/drm_syncobj.c 
>> b/drivers/gpu/drm/drm_syncobj.c
>> index 306c7b7e2770..eaeb038f97d7 100644
>> --- a/drivers/gpu/drm/drm_syncobj.c
>> +++ b/drivers/gpu/drm/drm_syncobj.c
>> @@ -1183,6 +1183,109 @@ drm_syncobj_signal_ioctl(struct drm_device 
>> *dev, void *data,
>>       return ret;
>>   }
>>   +int
>> +drm_syncobj_timeline_signal_ioctl(struct drm_device *dev, void *data,
>> +                  struct drm_file *file_private)
>> +{
>> +    struct drm_syncobj_timeline_array *args = data;
>> +    struct drm_syncobj **syncobjs;
>> +    struct dma_fence_chain **chains;
>> +    uint64_t *points;
>> +    uint32_t i, j, timeline_count = 0;
>> +    int ret;
>> +
>> +    if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
>> +        return -EOPNOTSUPP;
>> +
>> +    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;
>> +
>> +                fence = drm_syncobj_fence_get(syncobjs[i]);
>> +                chain = to_dma_fence_chain(fence);
>> +                if (chain) {
>> +                        struct dma_fence *iter;
>> +
>> +                        dma_fence_chain_for_each(iter, fence) {
>> +                                if (!iter)
>> +                                        break;
>> +                if (!dma_fence_is_signaled(iter)) {
>> +                    dma_fence_put(iter);
>> +                    DRM_ERROR("Client must guarantee all existing 
>> timeline points signaled before performing host signal operation!");
>> +                    ret = -EPERM;
>> +                    goto out;
>
>
> Sorry if I'm failing to remember whether we discussed this before.
>
>
> Signaling a point from the host should be fine even if the previous 
> points in the timeline are not signaled.
ok, will remove that checking.

>
> After all this can happen on the device side as well (out of order 
> signaling).
>
>
> I thought the thing we didn't want is out of order submission.
>
> Just checking the last chain node seqno against the host signal point 
> should be enough.
>
>
> What about simply returning -EPERM, we can warn the application from 
> userspace?
OK, will add that.

>
>
>> +                }
>> +                        }
>> +                }
>> +        }
>> +
>> +    points = kmalloc_array(args->count_handles, sizeof(*points),
>> +                   GFP_KERNEL);
>> +    if (!points) {
>> +        ret = -ENOMEM;
>> +        goto out;
>> +    }
>> +    if (!u64_to_user_ptr(args->points)) {
>> +        memset(points, 0, args->count_handles * sizeof(uint64_t));
>> +    } else if (copy_from_user(points, u64_to_user_ptr(args->points),
>> +                  sizeof(uint64_t) * args->count_handles)) {
>> +        ret = -EFAULT;
>> +        goto err_points;
>> +    }
>> +
>> +
>> +    for (i = 0; i < args->count_handles; i++) {
>> +        if (points[i])
>> +            timeline_count++;
>> +    }
>> +    chains = kmalloc_array(timeline_count, sizeof(void *), GFP_KERNEL);
>> +    if (!chains) {
>> +        ret = -ENOMEM;
>> +        goto err_points;
>> +    }
>> +    for (i = 0; i < timeline_count; i++) {
>> +        chains[i] = kzalloc(sizeof(struct dma_fence_chain), 
>> GFP_KERNEL);
>> +        if (!chains[i]) {
>> +            for (j = 0; j < i; j++)
>> +                kfree(chains[j]);
>> +            ret = -ENOMEM;
>> +            goto err_chains;
>> +        }
>> +    }
>> +
>> +    for (i = 0, j = 0; i < args->count_handles; i++) {
>> +        if (points[i]) {
>> +            struct dma_fence *fence = dma_fence_get_stub();
>> +
>> +            drm_syncobj_add_point(syncobjs[i], chains[j++],
>
>
> Isn't this breaking with j++ ?, it should be part of the for() loop 
> expression : for (i = 0, j = 0; i < arrags->count_handles; i++, j++)
>
>
> Otherwise j will not increment at the same pace as i.
I think that is intentional, because syncobj array could contain both 
binary and timeline. j is for timelien_count in this context.

-David
>
>
>> +                          fence, points[i]);
>> +            dma_fence_put(fence);
>> +        } else
>> +            drm_syncobj_assign_null_handle(syncobjs[i]);
>> +    }
>> +err_chains:
>> +    kfree(chains);
>> +err_points:
>> +    kfree(points);
>> +out:
>> +    drm_syncobj_array_free(syncobjs, args->count_handles);
>> +
>> +    return ret;
>> +}
>> +
>>   int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
>>                   struct drm_file *file_private)
>>   {
>> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
>> index 4c1e2e6579fa..fe00b74268eb 100644
>> --- a/include/uapi/drm/drm.h
>> +++ b/include/uapi/drm/drm.h
>> @@ -943,6 +943,7 @@ extern "C" {
>>   #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)
>>   #define DRM_IOCTL_SYNCOBJ_TRANSFER    DRM_IOWR(0xCC, struct 
>> drm_syncobj_transfer)
>> +#define DRM_IOCTL_SYNCOBJ_TIMELINE_SIGNAL    DRM_IOWR(0xCD, struct 
>> drm_syncobj_timeline_array)
>>     /**
>>    * Device specific ioctls should only be in their respective headers
>
>

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