drm/amdgpu/userq: use drm_exec in amdgpu_userq_fence_read_wptr

To access the bo from vm mapping first lock the root bo and
then the object bo of the mapping to make sure both locks
are taken safely.

Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 3aab50410653fe7eb35eb6f9c2b27e3549ab09e6)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
index 53a8944bab05acd55b9741b79a0b7e3e234bee5e..a41fb72dba9403fbc8aa148fba06ce33a8b00a7e 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
@@ -370,51 +370,48 @@ static int amdgpu_userq_fence_read_wptr(struct amdgpu_device *adev,
 {
        struct amdgpu_bo_va_mapping *mapping;
        struct amdgpu_bo *bo;
+       struct drm_exec exec;
        u64 addr, *ptr;
-       int r;
-
-       r = amdgpu_bo_reserve(queue->vm->root.bo, false);
-       if (r)
-               return r;
+       int ret;
 
        addr = queue->userq_prop->wptr_gpu_addr;
        addr &= AMDGPU_GMC_HOLE_MASK;
 
-       mapping = amdgpu_vm_bo_lookup_mapping(queue->vm, addr >> PAGE_SHIFT);
-       if (!mapping) {
-               amdgpu_bo_unreserve(queue->vm->root.bo);
-               DRM_ERROR("Failed to lookup amdgpu_bo_va_mapping\n");
-               return -EINVAL;
-       }
+       drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 2);
+       drm_exec_until_all_locked(&exec) {
+               ret = amdgpu_vm_lock_pd(queue->vm, &exec, 1);
+               drm_exec_retry_on_contention(&exec);
+               if (unlikely(ret))
+                       goto lock_error;
 
-       bo = amdgpu_bo_ref(mapping->bo_va->base.bo);
-       amdgpu_bo_unreserve(queue->vm->root.bo);
-       r = amdgpu_bo_reserve(bo, true);
-       if (r) {
-               amdgpu_bo_unref(&bo);
-               DRM_ERROR("Failed to reserve userqueue wptr bo");
-               return r;
+               mapping = amdgpu_vm_bo_lookup_mapping(queue->vm, addr >> PAGE_SHIFT);
+               if (!mapping) {
+                       ret = -EINVAL;
+                       goto lock_error;
+               }
+
+               ret = drm_exec_lock_obj(&exec, &mapping->bo_va->base.bo->tbo.base);
+               drm_exec_retry_on_contention(&exec);
+               if (unlikely(ret))
+                       goto lock_error;
        }
 
-       r = amdgpu_bo_kmap(bo, (void **)&ptr);
-       if (r) {
+       bo = mapping->bo_va->base.bo;
+       ret = amdgpu_bo_kmap(bo, (void **)&ptr);
+       if (ret) {
                DRM_ERROR("Failed mapping the userqueue wptr bo");
-               goto map_error;
+               goto lock_error;
        }
 
        *wptr = le64_to_cpu(*ptr);
 
        amdgpu_bo_kunmap(bo);
-       amdgpu_bo_unreserve(bo);
-       amdgpu_bo_unref(&bo);
-
+       drm_exec_fini(&exec);
        return 0;
 
-map_error:
-       amdgpu_bo_unreserve(bo);
-       amdgpu_bo_unref(&bo);
-
-       return r;
+lock_error:
+       drm_exec_fini(&exec);
+       return ret;
 }
 
 static void