mm/dynamic_hugetlb: replace spin_lock with mutex_lock and fix kabi broken

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6MH03
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. Use KABI_EXTEND to fix kabi broken.

Fixes: 0c06a1c0 ("mm/dynamic_hugetlb: add interface to configure the count of hugepages")
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>

include/linux/dynamic_hugetlb.h

@@ -66,7 +66,7 @@ enum huge_pages_pool_type {
 struct dhugetlb_pool {
 	int nid;
 	spinlock_t lock;
-	spinlock_t reserved_lock;
+	KABI_DEPRECATE(spinlock_t, reserved_lock)
 	atomic_t refcnt;
 	unsigned long normal_pages_disabled;
 
@@ -74,6 +74,18 @@ struct dhugetlb_pool {
 
 	unsigned long total_huge_pages;
 	struct huge_pages_pool hpages_pool[HUGE_PAGES_POOL_MAX];
+
+	/* The dhugetlb_pool structures is only used by core kernel, it is
+	 * also accessed only the memory cgroup and hugetlb core code and
+	 * so changes made to dhugetlb_pool structure should not affect
+	 * third-party kernel modules.
+	 */
+	KABI_EXTEND(struct mutex reserved_lock)
+
+	/*
+	 * The percpu_pool[] should only be used by dynamic hugetlb core.
+	 * External kernel modules should not used it.
+	 */
 	struct percpu_pages_pool percpu_pool[0];
 };
 

mm/dynamic_hugetlb.c

@@ -887,7 +887,7 @@ static int hugetlb_pool_create(struct mem_cgroup *memcg, unsigned long nid)
 		return -ENOMEM;
 
 	spin_lock_init(&hpool->lock);
-	spin_lock_init(&hpool->reserved_lock);
+	mutex_init(&hpool->reserved_lock);
 	hpool->nid = nid;
 	atomic_set(&hpool->refcnt, 1);
 
@@ -1000,7 +1000,7 @@ static ssize_t update_reserved_pages(struct mem_cgroup *memcg, char *buf, int hp
 	if (!get_hpool_unless_zero(hpool))
 		return -EINVAL;
 
-	spin_lock(&hpool->reserved_lock);
+	mutex_lock(&hpool->reserved_lock);
 	spin_lock(&hpool->lock);
 	hpages_pool = &hpool->hpages_pool[hpages_pool_idx];
 	if (nr_pages > hpages_pool->nr_huge_pages) {
@@ -1036,7 +1036,7 @@ static ssize_t update_reserved_pages(struct mem_cgroup *memcg, char *buf, int hp
 		hpages_pool->free_normal_pages += delta;
 	}
 	spin_unlock(&hpool->lock);
-	spin_unlock(&hpool->reserved_lock);
+	mutex_unlock(&hpool->reserved_lock);
 	put_hpool(hpool);
 	return 0;
 }