[PATCH v2] drm/amdgpu: fix the memleak caused by fence not released

[Le Ma <le.ma@amd.com>]

On systems with CONFIG_SLUB_DEBUG enabled, the memleak like below
will show up explicitly during driver unloading if created bo without
drm_timeline object before.

    BUG drm_sched_fence (Tainted: G           OE     ): Objects remaining in drm_sched_fence on __kmem_cache_shutdown()
    -----------------------------------------------------------------------------
    Call Trace:
    <TASK>
    dump_stack_lvl+0x4c/0x70
    dump_stack+0x14/0x20
    slab_err+0xb0/0xf0
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? flush_work+0x12/0x20
    ? srso_alias_return_thunk+0x5/0xfbef5
    __kmem_cache_shutdown+0x163/0x2e0
    kmem_cache_destroy+0x61/0x170
    drm_sched_fence_slab_fini+0x19/0x900

Thus call dma_fence_put properly to avoid the memleak.

v2: call dma_fence_put in amdgpu_gem_va_update_vm

Signed-off-by: Le Ma <le.ma@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 8b67aae6c2fe..00f1f34705c0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -759,7 +759,8 @@ static struct dma_fence *
 amdgpu_gem_va_update_vm(struct amdgpu_device *adev,
 			struct amdgpu_vm *vm,
 			struct amdgpu_bo_va *bo_va,
-			uint32_t operation)
+			uint32_t operation,
+			uint32_t syncobj_handle)
 {
 	struct dma_fence *fence = dma_fence_get_stub();
 	int r;
@@ -771,6 +772,9 @@ amdgpu_gem_va_update_vm(struct amdgpu_device *adev,
 	if (r)
 		goto error;
 
+	if (!syncobj_handle)
+		dma_fence_put(fence);
+
 	if (operation == AMDGPU_VA_OP_MAP ||
 	    operation == AMDGPU_VA_OP_REPLACE) {
 		r = amdgpu_vm_bo_update(adev, bo_va, false);
@@ -965,7 +969,8 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void *data,
 						    &timeline_chain);
 
 		fence = amdgpu_gem_va_update_vm(adev, &fpriv->vm, bo_va,
-						args->operation);
+						args->operation,
+						args->vm_timeline_syncobj_out);
 
 		if (!r)
 			amdgpu_gem_update_bo_mapping(filp, bo_va,
-- 
2.43.2