linux-kernel - [PATCH v3 10/13] drm/msm: Drop submit bo

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Message-Id: <20210727171143.2549475-11-robdclark@gmail.com>
Date:   Tue, 27 Jul 2021 10:11:26 -0700
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Rob Clark <robdclark@...omium.org>,
        Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        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 10/13] drm/msm: Drop submit bo_list

From: Rob Clark <robdclark@...omium.org>

This was only used to detect userspace including the same bo multiple
times in a submit.  But ww_mutex can already tell us this.

When we drop struct_mutex around the submit ioctl, we'd otherwise need
to lock the bo before adding it to the bo_list.  But since ww_mutex can
already tell us this, it is simpler just to remove the bo_list.

Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 drivers/gpu/drm/msm/msm_gem.c        |  1 -
 drivers/gpu/drm/msm/msm_gem.h        |  8 --------
 drivers/gpu/drm/msm/msm_gem_submit.c | 28 +++++++++++++---------------
 3 files changed, 13 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index a527a6b1d6ba..af199ef53d2f 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -1151,7 +1151,6 @@ static int msm_gem_new_impl(struct drm_device *dev,
 	msm_obj->flags = flags;
 	msm_obj->madv = MSM_MADV_WILLNEED;
 
-	INIT_LIST_HEAD(&msm_obj->submit_entry);
 	INIT_LIST_HEAD(&msm_obj->vmas);
 
 	*obj = &msm_obj->base;
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index a48114058ff9..f9e3ffb2309a 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -88,13 +88,6 @@ struct msm_gem_object {
 	 */
 	struct list_head mm_list;
 
-	/* Transiently in the process of submit ioctl, objects associated
-	 * with the submit are on submit->bo_list.. this only lasts for
-	 * the duration of the ioctl, so one bo can never be on multiple
-	 * submit lists.
-	 */
-	struct list_head submit_entry;
-
 	struct page **pages;
 	struct sg_table *sgt;
 	void *vaddr;
@@ -316,7 +309,6 @@ struct msm_gem_submit {
 	struct msm_gpu *gpu;
 	struct msm_gem_address_space *aspace;
 	struct list_head node;   /* node in ring submit list */
-	struct list_head bo_list;
 	struct ww_acquire_ctx ticket;
 	uint32_t seqno;		/* Sequence number of the submit on the ring */
 
diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index 2b158433a6e5..e11e4bb63695 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -63,7 +63,6 @@ static struct msm_gem_submit *submit_create(struct drm_device *dev,
 	submit->fault_dumped = false;
 
 	INIT_LIST_HEAD(&submit->node);
-	INIT_LIST_HEAD(&submit->bo_list);
 
 	return submit;
 }
@@ -143,7 +142,6 @@ static int submit_lookup_objects(struct msm_gem_submit *submit,
 
 	for (i = 0; i < args->nr_bos; i++) {
 		struct drm_gem_object *obj;
-		struct msm_gem_object *msm_obj;
 
 		/* normally use drm_gem_object_lookup(), but for bulk lookup
 		 * all under single table_lock just hit object_idr directly:
@@ -155,20 +153,9 @@ static int submit_lookup_objects(struct msm_gem_submit *submit,
 			goto out_unlock;
 		}
 
-		msm_obj = to_msm_bo(obj);
-
-		if (!list_empty(&msm_obj->submit_entry)) {
-			DRM_ERROR("handle %u at index %u already on submit list\n",
-					submit->bos[i].handle, i);
-			ret = -EINVAL;
-			goto out_unlock;
-		}
-
 		drm_gem_object_get(obj);
 
-		submit->bos[i].obj = msm_obj;
-
-		list_add_tail(&msm_obj->submit_entry, &submit->bo_list);
+		submit->bos[i].obj = to_msm_bo(obj);
 	}
 
 out_unlock:
@@ -299,6 +286,12 @@ static int submit_lock_objects(struct msm_gem_submit *submit)
 	return 0;
 
 fail:
+	if (ret == -EALREADY) {
+		DRM_ERROR("handle %u at index %u already on submit list\n",
+				submit->bos[i].handle, i);
+		ret = -EINVAL;
+	}
+
 	for (; i >= 0; i--)
 		submit_unlock_unpin_bo(submit, i);
 
@@ -315,6 +308,12 @@ static int submit_lock_objects(struct msm_gem_submit *submit)
 			slow_locked = contended;
 			goto retry;
 		}
+
+		/* Not expecting -EALREADY here, if the bo was already
+		 * locked, we should have gotten -EALREADY already from
+		 * the dma_resv_lock_interruptable() call.
+		 */
+		WARN_ON_ONCE(ret == -EALREADY);
 	}
 
 	return ret;
@@ -508,7 +507,6 @@ static void submit_cleanup(struct msm_gem_submit *submit, bool error)
 	for (i = 0; i < submit->nr_bos; i++) {
 		struct msm_gem_object *msm_obj = submit->bos[i].obj;
 		submit_cleanup_bo(submit, i, cleanup_flags);
-		list_del_init(&msm_obj->submit_entry);
 		if (error)
 			drm_gem_object_put(&msm_obj->base);
 	}
-- 
2.31.1