mm/page_alloc.c: fix 'zone_id' may be used uninitialized in this function warning

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: 71bd2e49c8c7 ("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>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 71ad97c96075cdd105d3f9bb23bb4084c8db9c5b..04021e37120e63f9fac05978821b69202a14a8d7 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6715,7 +6715,7 @@ 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);