linux-kernel - [PATCH v3 17/23] drm/msm: Remove obj->gpu

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Date:   Mon, 19 Oct 2020 13:46:18 -0700
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Daniel Vetter <daniel@...ll.ch>,
        Rob Clark <robdclark@...omium.org>,
        Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...ux.ie>,
        linux-arm-msm@...r.kernel.org (open list:DRM DRIVER FOR MSM ADRENO GPU),
        freedreno@...ts.freedesktop.org (open list:DRM DRIVER FOR MSM ADRENO
        GPU), linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v3 17/23] drm/msm: Remove obj->gpu

From: Rob Clark <robdclark@...omium.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)

Signed-off-by: Rob Clark <robdclark@...omium.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 092ed152999e..e4876498be47 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -775,7 +775,6 @@ 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);
@@ -791,7 +790,6 @@ 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 2f289c436ddd..f4e73c6f07bf 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 bcd9b4fa98b2..d0f625112a97 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -810,11 +810,6 @@ 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_locked(&msm_obj->base, submit->aspace, &iova);
-- 
2.26.2