Re: [PATCH] drm/i915/gvt: Make use of idr_find and idr_for_each_entry in dmabuf

[Zhenyu Wang]

On 2023.03.02 19:53:18 +0800, Cai Huoqing wrote:
> This patch uses the already existing IDR mechanism to simplify
> and improve the dmabuf code.
> 
> Using 'vgpu.object_idr' directly instead of 'dmabuf_obj_list_head'
> or 'dmabuf.list', because the dmabuf_obj can be found by 'idr_find'
> or 'idr_for_each_entry'.
> 
> Signed-off-by: Cai Huoqing <cai.huoqing@xxxxxxxxx>
> ---
>  drivers/gpu/drm/i915/gvt/dmabuf.c | 69 +++++++------------------------
>  drivers/gpu/drm/i915/gvt/dmabuf.h |  1 -
>  drivers/gpu/drm/i915/gvt/gvt.h    |  1 -
>  drivers/gpu/drm/i915/gvt/vgpu.c   |  1 -
>  4 files changed, 16 insertions(+), 56 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.c b/drivers/gpu/drm/i915/gvt/dmabuf.c
> index 6834f9fe40cf..7933bd843ae8 100644
> --- a/drivers/gpu/drm/i915/gvt/dmabuf.c
> +++ b/drivers/gpu/drm/i915/gvt/dmabuf.c
> @@ -133,21 +133,15 @@ static void dmabuf_gem_object_free(struct kref *kref)
>  	struct intel_vgpu_dmabuf_obj *obj =
>  		container_of(kref, struct intel_vgpu_dmabuf_obj, kref);
>  	struct intel_vgpu *vgpu = obj->vgpu;
> -	struct list_head *pos;
>  	struct intel_vgpu_dmabuf_obj *dmabuf_obj;
> +	int id;
>  
> -	if (vgpu && test_bit(INTEL_VGPU_STATUS_ACTIVE, vgpu->status) &&
> -	    !list_empty(&vgpu->dmabuf_obj_list_head)) {
> -		list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
> -			dmabuf_obj = list_entry(pos, struct intel_vgpu_dmabuf_obj, list);
> -			if (dmabuf_obj == obj) {
> -				list_del(pos);
> -				idr_remove(&vgpu->object_idr,
> -					   dmabuf_obj->dmabuf_id);
> -				kfree(dmabuf_obj->info);
> -				kfree(dmabuf_obj);
> -				break;
> -			}
> +	if (vgpu && test_bit(INTEL_VGPU_STATUS_ACTIVE, vgpu->status)) {
> +		idr_for_each_entry(&vgpu->object_idr, dmabuf_obj, id) {
> +			idr_remove(&vgpu->object_idr, id);
> +			kfree(dmabuf_obj->info);
> +			kfree(dmabuf_obj);

This is wrong, it is not to free all dmabuf objects, but just for target one.

> +			break;
>  		}
>  	} else {
>  		/* Free the orphan dmabuf_objs here */
> @@ -340,13 +334,11 @@ static struct intel_vgpu_dmabuf_obj *
>  pick_dmabuf_by_info(struct intel_vgpu *vgpu,
>  		    struct intel_vgpu_fb_info *latest_info)
>  {
> -	struct list_head *pos;
>  	struct intel_vgpu_fb_info *fb_info;
>  	struct intel_vgpu_dmabuf_obj *dmabuf_obj = NULL;
> -	struct intel_vgpu_dmabuf_obj *ret = NULL;
> +	int id;
>  
> -	list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
> -		dmabuf_obj = list_entry(pos, struct intel_vgpu_dmabuf_obj, list);
> +	idr_for_each_entry(&vgpu->object_idr, dmabuf_obj, id) {
>  		if (!dmabuf_obj->info)
>  			continue;
>  
> @@ -357,31 +349,11 @@ pick_dmabuf_by_info(struct intel_vgpu *vgpu,
>  		    (fb_info->drm_format_mod == latest_info->drm_format_mod) &&
>  		    (fb_info->drm_format == latest_info->drm_format) &&
>  		    (fb_info->width == latest_info->width) &&
> -		    (fb_info->height == latest_info->height)) {
> -			ret = dmabuf_obj;
> -			break;
> -		}

Maybe just keep original code's use of extra ret to not include this cumbersome diff?

> -	}
> -
> -	return ret;
> -}
> -
> -static struct intel_vgpu_dmabuf_obj *
> -pick_dmabuf_by_num(struct intel_vgpu *vgpu, u32 id)
> -{
> -	struct list_head *pos;
> -	struct intel_vgpu_dmabuf_obj *dmabuf_obj = NULL;
> -	struct intel_vgpu_dmabuf_obj *ret = NULL;
> -
> -	list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
> -		dmabuf_obj = list_entry(pos, struct intel_vgpu_dmabuf_obj, list);
> -		if (dmabuf_obj->dmabuf_id == id) {
> -			ret = dmabuf_obj;
> -			break;
> -		}
> +		    (fb_info->height == latest_info->height))
> +			return dmabuf_obj;
>  	}
>  
> -	return ret;
> +	return dmabuf_obj;
>  }
>  
>  static void update_fb_info(struct vfio_device_gfx_plane_info *gvt_dmabuf,
> @@ -477,11 +449,6 @@ int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args)
>  
>  	update_fb_info(gfx_plane_info, &fb_info);
>  
> -	INIT_LIST_HEAD(&dmabuf_obj->list);
> -	mutex_lock(&vgpu->dmabuf_lock);
> -	list_add_tail(&dmabuf_obj->list, &vgpu->dmabuf_obj_list_head);
> -	mutex_unlock(&vgpu->dmabuf_lock);
> -
>  	gvt_dbg_dpy("vgpu%d: %s new dmabuf_obj ref %d, id %d\n", vgpu->id,
>  		    __func__, kref_read(&dmabuf_obj->kref), ret);
>  
> @@ -508,7 +475,7 @@ int intel_vgpu_get_dmabuf(struct intel_vgpu *vgpu, unsigned int dmabuf_id)
>  
>  	mutex_lock(&vgpu->dmabuf_lock);
>  
> -	dmabuf_obj = pick_dmabuf_by_num(vgpu, dmabuf_id);
> +	dmabuf_obj = idr_find(&vgpu->object_idr, dmabuf_id);
>  	if (dmabuf_obj == NULL) {
>  		gvt_vgpu_err("invalid dmabuf id:%d\n", dmabuf_id);
>  		ret = -EINVAL;
> @@ -570,23 +537,19 @@ int intel_vgpu_get_dmabuf(struct intel_vgpu *vgpu, unsigned int dmabuf_id)
>  
>  void intel_vgpu_dmabuf_cleanup(struct intel_vgpu *vgpu)
>  {
> -	struct list_head *pos, *n;
>  	struct intel_vgpu_dmabuf_obj *dmabuf_obj;
> +	int id;
>  
>  	mutex_lock(&vgpu->dmabuf_lock);
> -	list_for_each_safe(pos, n, &vgpu->dmabuf_obj_list_head) {
> -		dmabuf_obj = list_entry(pos, struct intel_vgpu_dmabuf_obj, list);
> +	idr_for_each_entry(&vgpu->object_idr, dmabuf_obj, id) {
>  		dmabuf_obj->vgpu = NULL;
>  
> -		idr_remove(&vgpu->object_idr, dmabuf_obj->dmabuf_id);
> -		list_del(pos);
> -
> +		idr_remove(&vgpu->object_idr, id);
>  		/* dmabuf_obj might be freed in dmabuf_obj_put */
>  		if (dmabuf_obj->initref) {
>  			dmabuf_obj->initref = false;
>  			dmabuf_obj_put(dmabuf_obj);
>  		}
> -
>  	}
>  	mutex_unlock(&vgpu->dmabuf_lock);
>  }
> diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.h b/drivers/gpu/drm/i915/gvt/dmabuf.h
> index 3dcdb6570eda..93c0e00bdab9 100644
> --- a/drivers/gpu/drm/i915/gvt/dmabuf.h
> +++ b/drivers/gpu/drm/i915/gvt/dmabuf.h
> @@ -57,7 +57,6 @@ struct intel_vgpu_dmabuf_obj {
>  	__u32 dmabuf_id;
>  	struct kref kref;
>  	bool initref;
> -	struct list_head list;
>  };
>  
>  int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args);
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> index 2d65800d8e93..1100c789f207 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -211,7 +211,6 @@ struct intel_vgpu {
>  
>  	struct dentry *debugfs;
>  
> -	struct list_head dmabuf_obj_list_head;
>  	struct mutex dmabuf_lock;
>  	struct idr object_idr;
>  	struct intel_vgpu_vblank_timer vblank_timer;
> diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
> index 08ad1bd651f1..0a511cfef067 100644
> --- a/drivers/gpu/drm/i915/gvt/vgpu.c
> +++ b/drivers/gpu/drm/i915/gvt/vgpu.c
> @@ -329,7 +329,6 @@ int intel_gvt_create_vgpu(struct intel_vgpu *vgpu,
>  	vgpu->sched_ctl.weight = conf->weight;
>  	mutex_init(&vgpu->vgpu_lock);
>  	mutex_init(&vgpu->dmabuf_lock);
> -	INIT_LIST_HEAD(&vgpu->dmabuf_obj_list_head);
>  	INIT_RADIX_TREE(&vgpu->page_track_tree, GFP_KERNEL);
>  	idr_init_base(&vgpu->object_idr, 1);
>  	intel_vgpu_init_cfg_space(vgpu, 1);
> -- 
> 2.34.1
>

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