drm/amdgpu: create fence slab once when amdgpu module init.

This avoids problems with multiple GPUs.  For example,
if the first GPU failed before amdgpu_fence_init() was
called, amdgpu_fence_slab_ref is still 0 and it will
get decremented in amdgpu_fence_driver_fini().  This
will lead to a crash during init of the second GPU since
amdgpu_fence_slab_ref is not 0.

v2: add functions for init/exit instead of
    moving the variables into the driver.

Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 14 insertions, 11 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
index ba9c04283d01..7eb2fca871e8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -55,8 +55,21 @@ struct amdgpu_fence {
 };
 
 static struct kmem_cache *amdgpu_fence_slab;
-static atomic_t amdgpu_fence_slab_ref = ATOMIC_INIT(0);
 
+int amdgpu_fence_slab_init(void)
+{
+        amdgpu_fence_slab = kmem_cache_create(
+                "amdgpu_fence", sizeof(struct amdgpu_fence), 0,
+                SLAB_HWCACHE_ALIGN, NULL);
+        if (!amdgpu_fence_slab)
+                return -ENOMEM;
+        return 0;
+}
+
+void amdgpu_fence_slab_fini(void)
+{
+        kmem_cache_destroy(amdgpu_fence_slab);
+}
 /*
  * Cast helper
  */
@@ -396,13 +409,6 @@ int amdgpu_fence_driver_init_ring(struct amdgpu_ring *ring,
  */
 int amdgpu_fence_driver_init(struct amdgpu_device *adev)
 {
-        if (atomic_inc_return(&amdgpu_fence_slab_ref) == 1) {
-                amdgpu_fence_slab = kmem_cache_create(
-                        "amdgpu_fence", sizeof(struct amdgpu_fence), 0,
-                        SLAB_HWCACHE_ALIGN, NULL);
-                if (!amdgpu_fence_slab)
-                        return -ENOMEM;
-        }
         if (amdgpu_debugfs_fence_init(adev))
                 dev_err(adev->dev, "fence debugfs file creation failed\n");
 
@@ -441,9 +447,6 @@ void amdgpu_fence_driver_fini(struct amdgpu_device *adev)
                 kfree(ring->fence_drv.fences);
                 ring->fence_drv.initialized = false;
         }
-
-        if (atomic_dec_and_test(&amdgpu_fence_slab_ref))
-                kmem_cache_destroy(amdgpu_fence_slab);
 }
 
 /**