From:   Rob Clark <robdclark@gmail.com>
To:     dri-devel@lists.freedesktop.org
Cc:     Daniel Vetter <daniel@ffwll.ch>, linux-arm-msm@vger.kernel.org,
        Rob Clark <robdclark@chromium.org>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        Andrey Grodzovsky <andrey.grodzovsky@amd.com>,
        David Airlie <airlied@linux.ie>,
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] drm/scheduler: fix drm_sched_job_add_implicit_dependencies harder
Date:   Tue, 16 Nov 2021 07:55:45 -0800
Message-Id: <20211116155545.473311-1-robdclark@gmail.com>
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From: Rob Clark <robdclark@chromium.org>

drm_sched_job_add_dependency() could drop the last ref, so we need to do
the dma_fence_get() first.

Cc: Christian König <christian.koenig@amd.com>
Fixes: 9c2ba265352a drm/scheduler: ("use new iterator in drm_sched_job_add_implicit_dependencies v2")
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
Applies on top of "drm/scheduler: fix drm_sched_job_add_implicit_dependencies"
but I don't think that has a stable commit sha yet.

 drivers/gpu/drm/scheduler/sched_main.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 94fe51b3caa2..f91fb31ab7a7 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -704,12 +704,13 @@ int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 	int ret;
 
 	dma_resv_for_each_fence(&cursor, obj->resv, write, fence) {
-		ret = drm_sched_job_add_dependency(job, fence);
-		if (ret)
-			return ret;
-
 		/* Make sure to grab an additional ref on the added fence */
 		dma_fence_get(fence);
+		ret = drm_sched_job_add_dependency(job, fence);
+		if (ret) {
+			dma_fence_put(fence);
+			return ret;
+		}
 	}
 	return 0;
 }
-- 
2.33.1