[PATCH v4] hugetlb: Fix wrong use of nr_online_nodes

[Peng Liu <liupeng256@huawei.com>]

Certain systems are designed to have sparse/discontiguous nodes. In
this case, nr_online_nodes can not be used to walk through numa node.
Also, a valid node may be greater than nr_online_nodes.

However, in hugetlb, it is assumed that nodes are contiguous. Recheck
all the places that use nr_online_nodes, and repair them one by one.

Suggested-by: David Hildenbrand <david@redhat.com>
Fixes: 4178158ef8ca ("hugetlbfs: fix issue of preallocation of gigantic pages can't work")
Fixes: b5389086ad7b ("hugetlbfs: extend the definition of hugepages parameter to support node allocation")
Fixes: e79ce9832316 ("hugetlbfs: fix a truncation issue in hugepages parameter")
Fixes: f9317f77a6e0 ("hugetlb: clean up potential spectre issue warnings")
Signed-off-by: Peng Liu <liupeng256@huawei.com>
---
v3->v4:
 Make sure nid is valid before use node_online, and __alloc_bootmem_huge_page
 is no need to check node_online, which is suggested by Kefeng.

 mm/hugetlb.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b34f50156f7e..a386c5f94932 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2979,8 +2979,6 @@ int __alloc_bootmem_huge_page(struct hstate *h, int nid)
 	struct huge_bootmem_page *m = NULL; /* initialize for clang */
 	int nr_nodes, node;
 
-	if (nid != NUMA_NO_NODE && nid >= nr_online_nodes)
-		return 0;
 	/* do node specific alloc */
 	if (nid != NUMA_NO_NODE) {
 		m = memblock_alloc_try_nid_raw(huge_page_size(h), huge_page_size(h),
@@ -3088,7 +3086,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
 	}
 
 	/* do node specific alloc */
-	for (i = 0; i < nr_online_nodes; i++) {
+	for_each_online_node(i) {
 		if (h->max_huge_pages_node[i] > 0) {
 			hugetlb_hstate_alloc_pages_onenode(h, i);
 			node_specific_alloc = true;
@@ -4049,7 +4047,7 @@ static int __init hugetlb_init(void)
 			default_hstate.max_huge_pages =
 				default_hstate_max_huge_pages;
 
-			for (i = 0; i < nr_online_nodes; i++)
+			for_each_online_node(i)
 				default_hstate.max_huge_pages_node[i] =
 					default_hugepages_in_node[i];
 		}
@@ -4164,9 +4162,9 @@ static int __init hugepages_setup(char *s)
 				pr_warn("HugeTLB: architecture can't support node specific alloc, ignoring!\n");
 				return 0;
 			}
-			if (tmp >= nr_online_nodes)
+			if (tmp >= MAX_NUMNODES || !node_online(tmp))
 				goto invalid;
-			node = array_index_nospec(tmp, nr_online_nodes);
+			node = array_index_nospec(tmp, MAX_NUMNODES);
 			p += count + 1;
 			/* Parse hugepages */
 			if (sscanf(p, "%lu%n", &tmp, &count) != 1)
@@ -4294,7 +4292,7 @@ static int __init default_hugepagesz_setup(char *s)
 	 */
 	if (default_hstate_max_huge_pages) {
 		default_hstate.max_huge_pages = default_hstate_max_huge_pages;
-		for (i = 0; i < nr_online_nodes; i++)
+		for_each_online_node(i)
 			default_hstate.max_huge_pages_node[i] =
 				default_hugepages_in_node[i];
 		if (hstate_is_gigantic(&default_hstate))
-- 
2.25.1