[PATCH 5.15 179/279] powerpc/pseries: Fix numa FORM2 parsing fallback code

[Greg Kroah-Hartman]

From: Nicholas Piggin <npiggin@xxxxxxxxx>

[ Upstream commit 302039466f6a3b9421ecb9a6a2c528801dc24a86 ]

In case the FORM2 distance table from firmware is not the expected size,
there is fallback code that just populates the lookup table as local vs
remote.

However it then continues on to use the distance table. Fix.

Fixes: 1c6b5a7e7405 ("powerpc/pseries: Add support for FORM2 associativity")
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211109064900.2041386-2-npiggin@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/powerpc/mm/numa.c | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 53e9901409163..59d3cfcd78879 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -407,30 +407,26 @@ static void initialize_form2_numa_distance_lookup_table(void)
 
 	if (form2_distances_length != max_numa_index * max_numa_index) {
 		WARN(1, "Wrong NUMA distance information\n");
-		/* consider everybody else just remote. */
-		for (i = 0;  i < max_numa_index; i++) {
-			for (j = 0; j < max_numa_index; j++) {
-				int nodeA = numa_id_index_table[i];
-				int nodeB = numa_id_index_table[j];
-
-				if (nodeA == nodeB)
-					numa_distance_table[nodeA][nodeB] = LOCAL_DISTANCE;
-				else
-					numa_distance_table[nodeA][nodeB] = REMOTE_DISTANCE;
-			}
-		}
+		form2_distances = NULL; // don't use it
 	}
-
 	distance_index = 0;
 	for (i = 0;  i < max_numa_index; i++) {
 		for (j = 0; j < max_numa_index; j++) {
 			int nodeA = numa_id_index_table[i];
 			int nodeB = numa_id_index_table[j];
-
-			numa_distance_table[nodeA][nodeB] = form2_distances[distance_index++];
-			pr_debug("dist[%d][%d]=%d ", nodeA, nodeB, numa_distance_table[nodeA][nodeB]);
+			int dist;
+
+			if (form2_distances)
+				dist = form2_distances[distance_index++];
+			else if (nodeA == nodeB)
+				dist = LOCAL_DISTANCE;
+			else
+				dist = REMOTE_DISTANCE;
+			numa_distance_table[nodeA][nodeB] = dist;
+			pr_debug("dist[%d][%d]=%d ", nodeA, nodeB, dist);
 		}
 	}
+
 	of_node_put(root);
 }
 
-- 
2.33.0