[PATCH 03/21] drm/amdgpu: add amdgpu_pasid_free_delayed

[Chunming Zhou]

On 2018年01月10日 20:54, Christian König wrote:
> Free up a pasid after all fences signaled.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c | 73 +++++++++++++++++++++++++++++++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ids.h |  2 +
>   2 files changed, 75 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c
> index 5248a3232aff..63c9fb0361c0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c
> @@ -40,6 +40,12 @@
>    */
>   static DEFINE_IDA(amdgpu_pasid_ida);
>   
> +/* Helper to free pasid from a fence callback */
> +struct amdgpu_pasid_cb {
> +	struct dma_fence_cb cb;
> +	unsigned int pasid;
> +};
> +
>   /**
>    * amdgpu_pasid_alloc - Allocate a PASID
>    * @bits: Maximum width of the PASID in bits, must be at least 1
> @@ -75,6 +81,73 @@ void amdgpu_pasid_free(unsigned int pasid)
>   	ida_simple_remove(&amdgpu_pasid_ida, pasid);
>   }
>   
> +static void amdgpu_pasid_free_cb(struct dma_fence *fence,
> +				 struct dma_fence_cb *_cb)
> +{
> +	struct amdgpu_pasid_cb *cb =
> +		container_of(_cb, struct amdgpu_pasid_cb, cb);
> +
> +	amdgpu_pasid_free(cb->pasid);
> +	dma_fence_put(fence);
> +	kfree(cb);
> +}
> +
> +/**
> + * amdgpu_pasid_free_delayed - free pasid when fences signal
> + *
> + * @resv: reservation object with the fences to wait for
> + * @pasid: pasid to free
> + *
> + * Free the pasid only after all the fences in resv are signaled.
> + */
> +void amdgpu_pasid_free_delayed(struct reservation_object *resv,
> +			       unsigned int pasid)
> +{
> +	struct dma_fence *fence, **fences;
> +	struct amdgpu_pasid_cb *cb;
> +	unsigned count;
> +	int r;
> +
> +	r = reservation_object_get_fences_rcu(resv, NULL, &count, &fences);
> +	if (r) {
> +		/* Not enough memory to grab the fence list, as last resort
> +		 * block for all the fences to complete.
> +		 */
> +		reservation_object_wait_timeout_rcu(resv, true, false,
> +						    MAX_SCHEDULE_TIMEOUT);
> +		amdgpu_pasid_free(pasid);
> +		return;
> +	}
> +
> +	if (count == 0) {
> +		amdgpu_pasid_free(pasid);
> +		return;
> +	}
> +
> +	if (count == 1) {
> +		fence = fences[0];
> +		kfree(fences);
> +	} else {
> +		uint64_t context = dma_fence_context_alloc(1);
> +
> +		fence = &dma_fence_array_create(count, fences, context,
> +						1, false)->base;
Here needs to check if fence is NULL.

Regards,
David Zhou
> +	}
> +
> +	cb = kmalloc(sizeof(*cb), GFP_KERNEL);
> +	if (!cb) {
> +		/* Last resort when we are OOM */
> +		dma_fence_wait(fence, false);
> +		dma_fence_put(fence);
> +		amdgpu_pasid_free(pasid);
> +	} else {
> +		cb->pasid = pasid;
> +		if (dma_fence_add_callback(fence, &cb->cb,
> +					   amdgpu_pasid_free_cb))
> +			amdgpu_pasid_free_cb(fence, &cb->cb);
> +	}
> +}
> +
>   /*
>    * VMID manager
>    *
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.h
> index ad931fa570b3..38f37c16fc5e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.h
> @@ -69,6 +69,8 @@ struct amdgpu_vmid_mgr {
>   
>   int amdgpu_pasid_alloc(unsigned int bits);
>   void amdgpu_pasid_free(unsigned int pasid);
> +void amdgpu_pasid_free_delayed(struct reservation_object *resv,
> +			       unsigned int pasid);
>   
>   bool amdgpu_vmid_had_gpu_reset(struct amdgpu_device *adev,
>   			       struct amdgpu_vmid *id);