drm/amdgpu: Drop eviction lock when allocating PT BO

Re-take the eviction lock immediately again after the allocation is
completed, to fix circular locking warning with drm_buddy allocator.

Move amdgpu_vm_eviction_lock/unlock/trylock to amdgpu_vm.h as they are
called from multiple files.

Signed-off-by: Philip Yang <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: PhilipYangA

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -143,32 +143,6 @@ int amdgpu_vm_set_pasid(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 	return 0;
 }
 
-/*
- * vm eviction_lock can be taken in MMU notifiers. Make sure no reclaim-FS
- * happens while holding this lock anywhere to prevent deadlocks when
- * an MMU notifier runs in reclaim-FS context.
- */
-static inline void amdgpu_vm_eviction_lock(struct amdgpu_vm *vm)
-{
-	mutex_lock(&vm->eviction_lock);
-	vm->saved_flags = memalloc_noreclaim_save();
-}
-
-static inline int amdgpu_vm_eviction_trylock(struct amdgpu_vm *vm)
-{
-	if (mutex_trylock(&vm->eviction_lock)) {
-		vm->saved_flags = memalloc_noreclaim_save();
-		return 1;
-	}
-	return 0;
-}
-
-static inline void amdgpu_vm_eviction_unlock(struct amdgpu_vm *vm)
-{
-	memalloc_noreclaim_restore(vm->saved_flags);
-	mutex_unlock(&vm->eviction_lock);
-}
-
 /**
  * amdgpu_vm_bo_evicted - vm_bo is evicted
  *

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h

@@ -510,4 +510,30 @@ static inline uint64_t amdgpu_vm_tlb_seq(struct amdgpu_vm *vm)
 	return atomic64_read(&vm->tlb_seq);
 }
 
+/*
+ * vm eviction_lock can be taken in MMU notifiers. Make sure no reclaim-FS
+ * happens while holding this lock anywhere to prevent deadlocks when
+ * an MMU notifier runs in reclaim-FS context.
+ */
+static inline void amdgpu_vm_eviction_lock(struct amdgpu_vm *vm)
+{
+	mutex_lock(&vm->eviction_lock);
+	vm->saved_flags = memalloc_noreclaim_save();
+}
+
+static inline bool amdgpu_vm_eviction_trylock(struct amdgpu_vm *vm)
+{
+	if (mutex_trylock(&vm->eviction_lock)) {
+		vm->saved_flags = memalloc_noreclaim_save();
+		return true;
+	}
+	return false;
+}
+
+static inline void amdgpu_vm_eviction_unlock(struct amdgpu_vm *vm)
+{
+	memalloc_noreclaim_restore(vm->saved_flags);
+	mutex_unlock(&vm->eviction_lock);
+}
+
 #endif

drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c

@@ -597,7 +597,9 @@ static int amdgpu_vm_pt_alloc(struct amdgpu_device *adev,
 	if (entry->bo)
 		return 0;
 
+	amdgpu_vm_eviction_unlock(vm);
 	r = amdgpu_vm_pt_create(adev, vm, cursor->level, immediate, &pt);
+	amdgpu_vm_eviction_lock(vm);
 	if (r)
 		return r;