[PATCH] drm/msm/vma: Avoid lock in VM_BIND fence signaling path

[Rob Clark]

Use msm_gem_unpin_active(), similar to what is used in the GEM_SUBMIT
path.  This avoids needing to hold the obj lock, and the end result is
the same.  (As with GEM_SUBMIT, we know the fence isn't signaled yet.)

Reported-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxxxx>
Fixes: 2e6a8a1fe2b2 ("drm/msm: Add VM_BIND ioctl")
Signed-off-by: Rob Clark <robin.clark@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/msm_gem.c     | 3 +++
 drivers/gpu/drm/msm/msm_gem_vma.c | 9 ++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index da74f1413f94..74636646d80e 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -507,8 +507,11 @@ void msm_gem_unpin_locked(struct drm_gem_object *obj)
  */
 void msm_gem_unpin_active(struct drm_gem_object *obj)
 {
+	struct msm_drm_private *priv = obj->dev->dev_private;
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 
+	GEM_WARN_ON(!mutex_is_locked(&priv->lru.lock));
+
 	msm_obj->pin_count--;
 	GEM_WARN_ON(msm_obj->pin_count < 0);
 	update_lru_active(obj);
diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c b/drivers/gpu/drm/msm/msm_gem_vma.c
index 3a6c435d5105..1c6b0920c0d8 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -696,6 +696,7 @@ static struct dma_fence *
 msm_vma_job_run(struct drm_sched_job *_job)
 {
 	struct msm_vm_bind_job *job = to_msm_vm_bind_job(_job);
+	struct msm_drm_private *priv = job->vm->drm->dev_private;
 	struct msm_gem_vm *vm = to_msm_vm(job->vm);
 	struct drm_gem_object *obj;
 	int ret = vm->unusable ? -EINVAL : 0;
@@ -738,12 +739,14 @@ msm_vma_job_run(struct drm_sched_job *_job)
 	if (ret)
 		msm_gem_vm_unusable(job->vm);
 
+	mutex_lock(&priv->lru.lock);
+
 	job_foreach_bo (obj, job) {
-		msm_gem_lock(obj);
-		msm_gem_unpin_locked(obj);
-		msm_gem_unlock(obj);
+		msm_gem_unpin_active(obj);
 	}
 
+	mutex_unlock(&priv->lru.lock);
+
 	/* VM_BIND ops are synchronous, so no fence to wait on: */
 	return NULL;
 }
-- 
2.53.0