amdgpu: a NULL ->mm does not mean a thread is a kthread

Use the proper API instead.

Fixes: 70539bd ("drm/amd: Update MEC HQD loading code for KFD")
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Jens Axboe <[email protected]>
Reviewed-by: Felix Kuehling <[email protected]>
Reviewed-by: Jens Axboe <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Zhenyu Wang <[email protected]>
Cc: Zhi Wang <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

Author: Christoph Hellwig

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

@@ -196,7 +196,7 @@ uint8_t amdgpu_amdkfd_get_xgmi_hops_count(struct kgd_dev *dst, struct kgd_dev *s
 			pagefault_disable();				\
 			if ((mmptr) == current->mm) {			\
 				valid = !get_user((dst), (wptr));	\
-			} else if (current->mm == NULL) {		\
+			} else if (current->flags & PF_KTHREAD) {	\
 				kthread_use_mm(mmptr);			\
 				valid = !get_user((dst), (wptr));	\
 				kthread_unuse_mm(mmptr);		\