hugetlb: add lockdep_assert_held() calls for hugetlb_lock

After making hugetlb lock irq safe and separating some functionality
done under the lock, add some lockdep_assert_held to help verify
locking.

Link: https://lkml.kernel.org/r/20210409205254.242291-9-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@nec.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

@@ -1069,6 +1069,8 @@ static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
 static void enqueue_huge_page(struct hstate *h, struct page *page)
 {
 	int nid = page_to_nid(page);
+
+	lockdep_assert_held(&hugetlb_lock);
 	list_move(&page->lru, &h->hugepage_freelists[nid]);
 	h->free_huge_pages++;
 	h->free_huge_pages_node[nid]++;
@@ -1080,6 +1082,7 @@ static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
 	struct page *page;
 	bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);
 
+	lockdep_assert_held(&hugetlb_lock);
 	list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
 		if (nocma && is_migrate_cma_page(page))
 			continue;
@@ -1351,6 +1354,7 @@ static void remove_hugetlb_page(struct hstate *h, struct page *page,
 	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
 	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
 
+	lockdep_assert_held(&hugetlb_lock);
 	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
 		return;
 
@@ -1701,6 +1705,7 @@ static struct page *remove_pool_huge_page(struct hstate *h,
 	int nr_nodes, node;
 	struct page *page = NULL;
 
+	lockdep_assert_held(&hugetlb_lock);
 	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
 		/*
 		 * If we're returning unused surplus pages, only examine
@@ -1950,6 +1955,7 @@ static int gather_surplus_pages(struct hstate *h, long delta)
 	long needed, allocated;
 	bool alloc_ok = true;
 
+	lockdep_assert_held(&hugetlb_lock);
 	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
 	if (needed <= 0) {
 		h->resv_huge_pages += delta;
@@ -2043,6 +2049,7 @@ static void return_unused_surplus_pages(struct hstate *h,
 	struct page *page;
 	LIST_HEAD(page_list);
 
+	lockdep_assert_held(&hugetlb_lock);
 	/* Uncommit the reservation */
 	h->resv_huge_pages -= unused_resv_pages;
 
@@ -2530,6 +2537,7 @@ static void try_to_free_low(struct hstate *h, unsigned long count,
 	int i;
 	LIST_HEAD(page_list);
 
+	lockdep_assert_held(&hugetlb_lock);
 	if (hstate_is_gigantic(h))
 		return;
 
@@ -2571,6 +2579,7 @@ static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
 {
 	int nr_nodes, node;
 
+	lockdep_assert_held(&hugetlb_lock);
 	VM_BUG_ON(delta != -1 && delta != 1);
 
 	if (delta < 0) {