From c9c80b317d43a5398501c29fa4734a38c632215e Mon Sep 17 00:00:00 2001
From: Nico Pache <npache@redhat.com>
Date: Thu, 2 Sep 2021 14:58:08 -0700
Subject: [PATCH] mm/page_alloc.c: fix 'zone_id' may be used uninitialized in
 this function warning

References: bsc#1190208 (MM functional and performance backports)
Patch-mainline: v5.15-rc1
Git-commit: b346075fcf5dda7f9e9ae671703aae60e8a94564

When compiling with -Werror, cc1 will warn that 'zone_id' may be used
uninitialized in this function warning.

Initialize the zone_id as 0.

Its safe to assume that if the code reaches this point it has at least one
numa node with memory, so no need for an assertion before
init_unavilable_range.

Link: https://lkml.kernel.org/r/20210716210336.1114114-1-npache@redhat.com
Fixes: 122e093c1734 ("mm/page_alloc: fix memory map initialization for descending nodes")
Signed-off-by: Nico Pache <npache@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 mm/page_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0b0dbb081365..ec8a9d142fcf 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6752,7 +6752,7 @@ static void __init memmap_init(void)
 {
 	unsigned long start_pfn, end_pfn;
 	unsigned long hole_pfn = 0;
-	int i, j, zone_id, nid;
+	int i, j, zone_id = 0, nid;
 
 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
 		struct pglist_data *node = NODE_DATA(nid);