[PATCH v2 1/2] drm/amd/amdgpu: lock reservation object while creating shadow bo

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

ttm_bo_init checks that the reservation object is locked. This is
the caller's responsibility when resv != NULL. Otherwise, the inline
reservation object of the newly allocated buffer is used and must
explicitly be locked.

Uninterruptible w/w locks without an acquire context are always
successful.

v2: use ww_mutex_lock

Signed-off-by: Nicolai Hähnle <nicolai.haehnle at amd.com>
Reviewed-by: Edward O'Callaghan <funfunctor at folklore1984.net> (v1)
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 11c12c4d..4b2a5a9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -465,21 +465,30 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
 	amdgpu_ttm_placement_init(adev, &placement,
 				  placements, domain, flags);
 
 	r = amdgpu_bo_create_restricted(adev, size, byte_align, kernel,
 					domain, flags, sg, &placement,
 					resv, bo_ptr);
 	if (r)
 		return r;
 
 	if (amdgpu_need_backup(adev) && (flags & AMDGPU_GEM_CREATE_SHADOW)) {
+		if (!resv) {
+			r = ww_mutex_lock(&(*bo_ptr)->tbo.resv->lock, NULL);
+			WARN_ON(r != 0);
+		}
+
 		r = amdgpu_bo_create_shadow(adev, size, byte_align, (*bo_ptr));
+
+		if (!resv)
+			ww_mutex_unlock(&(*bo_ptr)->tbo.resv->lock);
+
 		if (r)
 			amdgpu_bo_unref(bo_ptr);
 	}
 
 	return r;
 }
 
 int amdgpu_bo_backup_to_shadow(struct amdgpu_device *adev,
 			       struct amdgpu_ring *ring,
 			       struct amdgpu_bo *bo,
-- 
2.7.4