[PATCH v2] powerpc/numa: Limit possible nodes to within num_possible_nodes

[Srikar Dronamraju]

MAX_NUMNODES is a theoretical maximum number of nodes thats is supported
by the kernel. Device tree properties exposes the number of possible
nodes on the current platform. The kernel would detected this and would
use it for most of its resource allocations.  If the platform now
increases the nodes to over what was already exposed, then it may lead
to inconsistencies. Hence limit it to the already exposed nodes.

Suggested-by: Nathan Lynch <nathanl at linux.ibm.com>
Cc: linuxppc-dev <linuxppc-dev at lists.ozlabs.org>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Nicholas Piggin <npiggin at gmail.com>
Cc: Anton Blanchard <anton at ozlabs.org>
Cc: Nathan Lynch <nathanl at linux.ibm.com>
Cc: Tyrel Datwyler <tyreld at linux.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar at linux.vnet.ibm.com>

Changelog v1 -> v2:
v1: https://lore.kernel.org/linuxppc-dev/20200715120534.3673-1-srikar@linux.vnet.ibm.com/t/#u
	Use nr_node_ids instead of num_possible_nodes() When nodes are
	sparse like in PowerNV, nr_node_ids gets the right value unlike
	num_possible_nodes()

Signed-off-by: Srikar Dronamraju <srikar at linux.vnet.ibm.com>
---
 arch/powerpc/mm/numa.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index e437a9ac4956..383359272270 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -221,7 +221,7 @@ static void initialize_distance_lookup_table(int nid,
 	}
 }
 
-/* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
+/* Returns nid in the range [0..nr_node_ids], or -1 if no useful numa
  * info is found.
  */
 static int associativity_to_nid(const __be32 *associativity)
@@ -235,7 +235,7 @@ static int associativity_to_nid(const __be32 *associativity)
 		nid = of_read_number(&associativity[min_common_depth], 1);
 
 	/* POWER4 LPAR uses 0xffff as invalid node */
-	if (nid == 0xffff || nid >= MAX_NUMNODES)
+	if (nid == 0xffff || nid >= nr_node_ids)
 		nid = NUMA_NO_NODE;
 
 	if (nid > 0 &&
@@ -448,7 +448,7 @@ static int of_drconf_to_nid_single(struct drmem_lmb *lmb)
 		index = lmb->aa_index * aa.array_sz + min_common_depth - 1;
 		nid = of_read_number(&aa.arrays[index], 1);
 
-		if (nid == 0xffff || nid >= MAX_NUMNODES)
+		if (nid == 0xffff || nid >= nr_node_ids)
 			nid = default_nid;
 
 		if (nid > 0) {
-- 
2.17.1