Re: [Freedreno] [PATCH 08/14] drm/msm: Remove obj->gpu

From: Jordan Crouse <jcrouse@codeaurora.org>
To: Rob Clark <robdclark@gmail.com>
Cc: dri-devel@lists.freedesktop.org,
	Rob Clark <robdclark@chromium.org>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU" 
	<freedreno@lists.freedesktop.org>,
	David Airlie <airlied@linux.ie>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU" 
	<linux-arm-msm@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	Daniel Vetter <daniel@ffwll.ch>, Sean Paul <sean@poorly.run>
Subject: Re: [Freedreno] [PATCH 08/14] drm/msm: Remove obj->gpu
Date: Mon, 5 Oct 2020 08:28:58 -0600	[thread overview]
Message-ID: <20201005142858.GG4204@jcrouse1-lnx.qualcomm.com> (raw)
In-Reply-To: <20201004192152.3298573-9-robdclark@gmail.com>

On Sun, Oct 04, 2020 at 12:21:40PM -0700, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
> 
> It cannot be atomically updated with obj->active_count, and the only
> purpose is a useless WARN_ON() (which becomes a buggy WARN_ON() once
> retire_submits() is not serialized with incoming submits via
> struct_mutex)

Somebody will prove me wrong but the longer we go without 2D the less likely it
is that we'll ever see it.

Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>

> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>  drivers/gpu/drm/msm/msm_gem.c | 2 --
>  drivers/gpu/drm/msm/msm_gem.h | 1 -
>  drivers/gpu/drm/msm/msm_gpu.c | 5 -----
>  3 files changed, 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index b04ed8b52f9d..c52a3969e60b 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -753,7 +753,6 @@ void msm_gem_active_get(struct drm_gem_object *obj, struct msm_gpu *gpu)
>  
>  	if (!atomic_fetch_inc(&msm_obj->active_count)) {
>  		mutex_lock(&priv->mm_lock);
> -		msm_obj->gpu = gpu;
>  		list_del_init(&msm_obj->mm_list);
>  		list_add_tail(&msm_obj->mm_list, &gpu->active_list);
>  		mutex_unlock(&priv->mm_lock);
> @@ -769,7 +768,6 @@ void msm_gem_active_put(struct drm_gem_object *obj)
>  
>  	if (!atomic_dec_return(&msm_obj->active_count)) {
>  		mutex_lock(&priv->mm_lock);
> -		msm_obj->gpu = NULL;
>  		list_del_init(&msm_obj->mm_list);
>  		list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
>  		mutex_unlock(&priv->mm_lock);
> diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
> index e05b1530aca6..61147bd96b06 100644
> --- a/drivers/gpu/drm/msm/msm_gem.h
> +++ b/drivers/gpu/drm/msm/msm_gem.h
> @@ -64,7 +64,6 @@ struct msm_gem_object {
>  	 *
>  	 */
>  	struct list_head mm_list;
> -	struct msm_gpu *gpu;     /* non-null if active */
>  
>  	/* Transiently in the process of submit ioctl, objects associated
>  	 * with the submit are on submit->bo_list.. this only lasts for
> diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
> index fd3fc6f36ab1..c9ff19a75169 100644
> --- a/drivers/gpu/drm/msm/msm_gpu.c
> +++ b/drivers/gpu/drm/msm/msm_gpu.c
> @@ -800,11 +800,6 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
>  		struct drm_gem_object *drm_obj = &msm_obj->base;
>  		uint64_t iova;
>  
> -		/* can't happen yet.. but when we add 2d support we'll have
> -		 * to deal w/ cross-ring synchronization:
> -		 */
> -		WARN_ON(is_active(msm_obj) && (msm_obj->gpu != gpu));
> -
>  		/* submit takes a reference to the bo and iova until retired: */
>  		drm_gem_object_get(&msm_obj->base);
>  		msm_gem_get_and_pin_iova(&msm_obj->base, submit->aspace, &iova);
> -- 
> 2.26.2
> 
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> Freedreno@lists.freedesktop.org
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