dhugetlb: use mutex lock in update_reserve_pages()

hulk inclusion
category: bugfix
bugzilla: 46904, https://gitee.com/openeuler/kernel/issues/I6KOXL
CVE: NA

--------------------------------

When memory is fragmented, update_reserve_pages() may call migrate_pages()
to collect continuous memory. This function can sleep, so we should use
mutex lock instead of spin lock.

Fixes: 3eb69101b5e6 ("mm: Add two interface for dhugetlb")
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NNanyong Sun <sunnanyong@huawei.com>
Reviewed-by: Ntong tiangen <tongtiangen@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>

include/linux/hugetlb.h

@@ -696,7 +696,7 @@ struct small_page_pool {
 struct dhugetlb_pool {
 	int nid;
 	spinlock_t lock;
-	spinlock_t reserved_lock;
+	struct mutex reserved_lock;
 	atomic_t refcnt;
 
 	struct mem_cgroup *attach_memcg;

mm/hugetlb.c

@@ -3327,7 +3327,7 @@ struct dhugetlb_pool *hpool_alloc(unsigned long nid)
 		return NULL;
 
 	spin_lock_init(&hpool->lock);
-	spin_lock_init(&hpool->reserved_lock);
+	mutex_init(&hpool->reserved_lock);
 	hpool->nid = nid;
 	atomic_set(&hpool->refcnt, 1);
 	INIT_LIST_HEAD(&hpool->dhugetlb_1G_freelists);

mm/memcontrol.c

@@ -4950,9 +4950,9 @@ static int update_reserve_pages(struct kernfs_open_file *of,
 	hpool = get_dhugetlb_pool_from_memcg(memcg);
 	if (!hpool)
 		return -EINVAL;
-	spin_lock(&hpool->reserved_lock);
+	mutex_lock(&hpool->reserved_lock);
 	dhugetlb_reserve_hugepages(hpool, size, gigantic);
-	spin_unlock(&hpool->reserved_lock);
+	mutex_unlock(&hpool->reserved_lock);
 	dhugetlb_pool_put(hpool);
 	return 0;
 }