linux-kernel - [PATCH] gpu: drm: remove redundant dma_fence_put() when drm_sched_job_add

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Date:   Mon, 25 Apr 2022 16:36:45 +0800
From:   Hangyu Hua <hbh25y@...il.com>
To:     yuq825@...il.com, airlied@...ux.ie, daniel@...ll.ch,
        andrey.grodzovsky@....com
Cc:     dri-devel@...ts.freedesktop.org, lima@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, Hangyu Hua <hbh25y@...il.com>
Subject: [PATCH] gpu: drm: remove redundant dma_fence_put() when drm_sched_job_add_dependency() fails

When drm_sched_job_add_dependency() fails, dma_fence_put() will be called
internally. Calling it again after drm_sched_job_add_dependency() finishes
may result in a dangling pointer.

Fix this by removing redundant dma_fence_put().

Signed-off-by: Hangyu Hua <hbh25y@...il.com>
---
 drivers/gpu/drm/lima/lima_gem.c        | 1 -
 drivers/gpu/drm/scheduler/sched_main.c | 1 -
 2 files changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
index 55bb1ec3c4f7..99c8e7f6bb1c 100644
--- a/drivers/gpu/drm/lima/lima_gem.c
+++ b/drivers/gpu/drm/lima/lima_gem.c
@@ -291,7 +291,6 @@ static int lima_gem_add_deps(struct drm_file *file, struct lima_submit *submit)
 
 		err = drm_sched_job_add_dependency(&submit->task->base, fence);
 		if (err) {
-			dma_fence_put(fence);
 			return err;
 		}
 	}
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index b81fceb0b8a2..ebab9eca37a8 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -708,7 +708,6 @@ int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 		dma_fence_get(fence);
 		ret = drm_sched_job_add_dependency(job, fence);
 		if (ret) {
-			dma_fence_put(fence);
 			return ret;
 		}
 	}
-- 
2.25.1