drm/amdgpu: add a spinlock to wb allocation

As we use wb slots more dynamically, we need to lock
access to avoid racing on allocation or free.

Reviewed-by: Shaoyun.liu <shaoyunl@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index cac0ca64367b..f87d53e183c3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -502,6 +502,7 @@ struct amdgpu_wb {
 	uint64_t		gpu_addr;
 	u32			num_wb;	/* Number of wb slots actually reserved for amdgpu. */
 	unsigned long		used[DIV_ROUND_UP(AMDGPU_MAX_WB, BITS_PER_LONG)];
+	spinlock_t		lock;
 };
 
 int amdgpu_device_wb_get(struct amdgpu_device *adev, u32 *wb);