Re: [PATCH 2/2] drm/amdgpu: add the interface of waiting multiple fences (v4)

[Gustavo Padovan <gustavo@padovan.org>]

Hi Alex,

2016-11-04 Alex Deucher <alexdeucher@gmail.com>:

> From: Junwei Zhang <Jerry.Zhang@amd.com>
> 
> v2: agd: rebase and squash in all the previous optimizations and
> changes so everything compiles.
> v3: squash in Slava's 32bit build fix
> v4: rebase on drm-next (fence -> dma_fence),
>     squash in Monk's ioctl update patch
> 
> Signed-off-by: Junwei Zhang <Jerry.Zhang@amd.com>
> Reviewed-by: Monk Liu <monk.liu@amd.com>
> Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h     |   2 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c  | 173 ++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c |   1 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c  |   2 +-
>  include/uapi/drm/amdgpu_drm.h           |  28 ++++++
>  5 files changed, 205 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index dc98ceb..7a94a3c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1212,6 +1212,8 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
>  			struct drm_file *filp);
>  int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp);
>  int amdgpu_cs_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *filp);
> +int amdgpu_cs_wait_fences_ioctl(struct drm_device *dev, void *data,
> +				struct drm_file *filp);
>  
>  int amdgpu_gem_metadata_ioctl(struct drm_device *dev, void *data,
>  				struct drm_file *filp);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index 2728805..2004836 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -1130,6 +1130,179 @@ int amdgpu_cs_wait_ioctl(struct drm_device *dev, void *data,
>  }
>  
>  /**
> + * amdgpu_cs_get_fence - helper to get fence from drm_amdgpu_fence
> + *
> + * @adev: amdgpu device
> + * @filp: file private
> + * @user: drm_amdgpu_fence copied from user space
> + */
> +static struct dma_fence *amdgpu_cs_get_fence(struct amdgpu_device *adev,
> +					     struct drm_file *filp,
> +					     struct drm_amdgpu_fence *user)
> +{
> +	struct amdgpu_ring *ring;
> +	struct amdgpu_ctx *ctx;
> +	struct dma_fence *fence;
> +	int r;
> +
> +	r = amdgpu_cs_get_ring(adev, user->ip_type, user->ip_instance,
> +			       user->ring, &ring);
> +	if (r)
> +		return ERR_PTR(r);
> +
> +	ctx = amdgpu_ctx_get(filp->driver_priv, user->ctx_id);
> +	if (ctx == NULL)
> +		return ERR_PTR(-EINVAL);
> +
> +	fence = amdgpu_ctx_get_fence(ctx, ring, user->seq_no);
> +	amdgpu_ctx_put(ctx);
> +
> +	return fence;
> +}
> +
> +/**
> + * amdgpu_cs_wait_all_fence - wait on all fences to signal
> + *
> + * @adev: amdgpu device
> + * @filp: file private
> + * @wait: wait parameters
> + * @fences: array of drm_amdgpu_fence
> + */
> +static int amdgpu_cs_wait_all_fences(struct amdgpu_device *adev,
> +				     struct drm_file *filp,
> +				     union drm_amdgpu_wait_fences *wait,
> +				     struct drm_amdgpu_fence *fences)
> +{
> +	uint32_t fence_count = wait->in.fence_count;
> +	unsigned i;
> +	long r = 1;
> +
> +	for (i = 0; i < fence_count; i++) {
> +		struct dma_fence *fence;
> +		unsigned long timeout = amdgpu_gem_timeout(wait->in.timeout_ns);
> +
> +		fence = amdgpu_cs_get_fence(adev, filp, &fences[i]);
> +		if (IS_ERR(fence))
> +			return PTR_ERR(fence);
> +		else if (!fence)
> +			continue;
> +
> +		r = dma_fence_wait_timeout(fence, true, timeout);
> +		if (r < 0)
> +			return r;
> +
> +		if (r == 0)
> +			break;
> +	}
> +
> +	memset(wait, 0, sizeof(*wait));
> +	wait->out.status = (r > 0);
> +
> +	return 0;
> +}
> +
> +/**
> + * amdgpu_cs_wait_any_fence - wait on any fence to signal
> + *
> + * @adev: amdgpu device
> + * @filp: file private
> + * @wait: wait parameters
> + * @fences: array of drm_amdgpu_fence
> + */
> +static int amdgpu_cs_wait_any_fence(struct amdgpu_device *adev,
> +				    struct drm_file *filp,
> +				    union drm_amdgpu_wait_fences *wait,
> +				    struct drm_amdgpu_fence *fences)
> +{
> +	unsigned long timeout = amdgpu_gem_timeout(wait->in.timeout_ns);
> +	uint32_t fence_count = wait->in.fence_count;
> +	uint32_t first = ~0;
> +	struct dma_fence **array;
> +	unsigned i;
> +	long r;
> +
> +	/* Prepare the fence array */
> +	array = (struct dma_fence **)kcalloc(fence_count, sizeof(struct dma_fence *),
> +			GFP_KERNEL);
> +	if (array == NULL)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < fence_count; i++) {
> +		struct dma_fence *fence;
> +
> +		fence = amdgpu_cs_get_fence(adev, filp, &fences[i]);
> +		if (IS_ERR(fence)) {
> +			r = PTR_ERR(fence);
> +			goto err_free_fence_array;
> +		} else if (fence) {
> +			array[i] = fence;
> +		} else { /* NULL, the fence has been already signaled */
> +			r = 1;
> +			goto out;
> +		}
> +	}
> +
> +	r = dma_fence_wait_any_timeout(array, fence_count, true, timeout, &first);
> +	if (r < 0)
> +		goto err_free_fence_array;
> +
> +out:
> +	memset(wait, 0, sizeof(*wait));
> +	wait->out.status = (r > 0);
> +	wait->out.first_signaled = first;
> +	/* set return value 0 to indicate success */
> +	r = 0;
> +
> +err_free_fence_array:
> +	for (i = 0; i < fence_count; i++)
> +		dma_fence_put(array[i]);
> +	kfree(array);
> +
> +	return r;
> +}
> +
> +/**
> + * amdgpu_cs_wait_fences_ioctl - wait for multiple command submissions to finish
> + *
> + * @dev: drm device
> + * @data: data from userspace
> + * @filp: file private
> + */
> +int amdgpu_cs_wait_fences_ioctl(struct drm_device *dev, void *data,
> +				struct drm_file *filp)
> +{
> +	struct amdgpu_device *adev = dev->dev_private;
> +	union drm_amdgpu_wait_fences *wait = data;
> +	uint32_t fence_count = wait->in.fence_count;
> +	struct drm_amdgpu_fence *fences_user;
> +	struct drm_amdgpu_fence *fences;
> +	int r;
> +
> +	/* Get the fences from userspace */
> +	fences = kmalloc_array(fence_count, sizeof(struct drm_amdgpu_fence),
> +			GFP_KERNEL);
> +	if (fences == NULL)
> +		return -ENOMEM;
> +
> +	fences_user = (void __user *)(unsigned long)(wait->in.fences);
> +	if (copy_from_user(fences, fences_user,
> +		sizeof(struct drm_amdgpu_fence) * fence_count)) {
> +		r = -EFAULT;
> +		goto err_free_fences;
> +	}
> +
> +	if (wait->in.wait_all)
> +		r = amdgpu_cs_wait_all_fences(adev, filp, wait, fences);
> +	else
> +		r = amdgpu_cs_wait_any_fence(adev, filp, wait, fences);

I wonder if it wouldn't be better if we use fence_array here and
register callbacks to get notfied of the first signaled fence the "any" case.
It seems to me that we could simplify this code by using a fence_array.

Gustavo

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