drm/amdkfd: flag added to handle errors from svm validate and map

If a return error is raised during validation and mapping of a
prange, this flag is set. It is a rare occurrence, but it could happen
when `amdgpu_hmm_range_get_pages_done` returns true. In such cases,
the caller should retry. However, it is important to ensure that the
prange is updated correctly during the retry.

Signed-off-by: Alex Sierra <[email protected]>
Reviewed-by: Felix Kuehling <[email protected]>

Author: alexsierrag

drivers/gpu/drm/amd/amdkfd/kfd_svm.c

@@ -821,7 +821,7 @@ svm_range_is_same_attrs(struct kfd_process *p, struct svm_range *prange,
 		}
 	}
 
-	return true;
+	return !prange->is_error_flag;
 }
 
 /**
@@ -1655,6 +1655,7 @@ static int svm_range_validate_and_map(struct mm_struct *mm,
 unreserve_out:
 	svm_range_unreserve_bos(&ctx);
 
+	prange->is_error_flag = !!r;
 	if (!r)
 		prange->validate_timestamp = ktime_get_boottime();
 

drivers/gpu/drm/amd/amdkfd/kfd_svm.h

@@ -133,6 +133,7 @@ struct svm_range {
 	DECLARE_BITMAP(bitmap_aip, MAX_GPU_INSTANCE);
 	bool				validated_once;
 	bool				mapped_to_gpu;
+	bool				is_error_flag;
 };
 
 static inline void svm_range_lock(struct svm_range *prange)