Date:   Fri, 3 Mar 2023 21:18:12 +0800
From:   Cai Huoqing <cai.huoqing@linux.dev>
To:     Zhenyu Wang <zhenyuw@linux.intel.com>
Cc:     Zhi Wang <zhi.a.wang@intel.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        intel-gvt-dev@lists.freedesktop.org,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/i915/gvt: Make use of idr_find and
 idr_for_each_entry in dmabuf
Message-ID: <ZAHzlML6iAm/bgB2@chq-MS-7D45>
References: <20230302115318.79487-1-cai.huoqing@linux.dev>
 <ZAGd0CeJ1OF6yCfg@debian-scheme>
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On 03 3月 23 15:12:16, Zhenyu Wang wrote:
> 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@linux.dev>
> > ---
> >  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.
Indeed, I will use idr_find for the target.

> 
> > +			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?
Ok, will revert 'ret' related.

Thanks,
Cai-
> 
> > -	}
> > -
> > -	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
> >