hugetlb: fix wrong use of nr_online_nodes

Patch series "hugetlb: Fix some incorrect behavior", v3.

This series fix three bugs of hugetlb:
1) Invalid use of nr_online_nodes;
2) Inconsistency between 1G hugepage and 2M hugepage;
3) Useless information in dmesg.


This patch (of 4):

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.

For sparse/discontiguous nodes, the current code may treat a valid node
as invalid, and will fail to allocate all hugepages on a valid node that
"nid >= nr_online_nodes".

As David suggested:

	if (tmp >= nr_online_nodes)
		goto invalid;

Just imagine node 0 and node 2 are online, and node 1 is offline. 
Assuming that "node < 2" is valid is wrong.  

Recheck all the places that use nr_online_nodes, and repair them one by
one.

[liupeng256@huawei.com: v4]
  Link: https://lkml.kernel.org/r/20220416103526.3287348-1-liupeng256@huawei.com
Link: https://lkml.kernel.org/r/20220413032915.251254-1-liupeng256@huawei.com
Link: https://lkml.kernel.org/r/20220413032915.251254-2-liupeng256@huawei.com
Fixes: 4178158e ("hugetlbfs: fix issue of preallocation of gigantic pages can't work")
Fixes: b5389086 ("hugetlbfs: extend the definition of hugepages parameter to support node allocation")
Fixes: e79ce983 ("hugetlbfs: fix a truncation issue in hugepages parameter")
Fixes: f9317f77 ("hugetlb: clean up potential spectre issue warnings")
Signed-off-by: NPeng Liu <liupeng256@huawei.com>
Suggested-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: NDavidlohr Bueso <dave@stgolabs.net>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Cc: Zhenguo Yao <yaozhenguo1@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Liu Yuntao <liuyuntao10@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

mm/hugetlb.c

@@ -2984,8 +2984,6 @@ 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),
@@ -3093,7 +3091,7 @@ 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;
@@ -4057,7 +4055,7 @@ 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];
 		}
@@ -4172,9 +4170,9 @@ 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)
@@ -4302,7 +4300,7 @@ 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))