mm/hugetlb: create hugetlb cgroup file in hugetlb_init

Build kernel with CONFIG_HUGETLBFS=y,CONFIG_HUGETLB_PAGE=y and
CONFIG_CGROUP_HUGETLB=y, then specify hugepagesz=xx boot option, system
will fail to boot.

This failure is caused by following code path:

  setup_hugepagesz
    hugetlb_add_hstate
      hugetlb_cgroup_file_init
        cgroup_add_cftypes
          kzalloc <--slab is *not available* yet

For this path, slab is not available yet, so memory allocated will be
failed, and cause WARN_ON() in hugetlb_cgroup_file_init().

So I move hugetlb_cgroup_file_init() into hugetlb_init().

[akpm@linux-foundation.org: tweak coding-style, remove pointless __init on inlined function]
[akpm@linux-foundation.org: fix warning]
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 18 insertions, 12 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e5318c7793ae..4f3ea0b1e57c 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1906,14 +1906,12 @@ static int __init hugetlb_init(void)
                 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
 
         hugetlb_init_hstates();
-
         gather_bootmem_prealloc();
-
         report_hugepages();
 
         hugetlb_sysfs_init();
-
         hugetlb_register_all_nodes();
+        hugetlb_cgroup_file_init();
 
         return 0;
 }
@@ -1943,13 +1941,6 @@ void __init hugetlb_add_hstate(unsigned order)
         h->next_nid_to_free = first_node(node_states[N_MEMORY]);
         snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
                                         huge_page_size(h)/1024);
-        /*
-         * Add cgroup control files only if the huge page consists
-         * of more than two normal pages. This is because we use
-         * page[2].lru.next for storing cgoup details.
-         */
-        if (order >= HUGETLB_CGROUP_MIN_ORDER)
-                hugetlb_cgroup_file_init(hugetlb_max_hstate - 1);
 
         parsed_hstate = h;
 }
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index b5bde7a5c017..9cea7de22ffb 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -333,7 +333,7 @@ static char *mem_fmt(char *buf, int size, unsigned long hsize)
         return buf;
 }
 
-int __init hugetlb_cgroup_file_init(int idx)
+static void __init __hugetlb_cgroup_file_init(int idx)
 {
         char buf[32];
         struct cftype *cft;
@@ -375,7 +375,22 @@ int __init hugetlb_cgroup_file_init(int idx)
 
         WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files));
 
-        return 0;
+        return;
+}
+
+void __init hugetlb_cgroup_file_init(void)
+{
+        struct hstate *h;
+
+        for_each_hstate(h) {
+                /*
+                 * Add cgroup control files only if the huge page consists
+                 * of more than two normal pages. This is because we use
+                 * page[2].lru.next for storing cgroup details.
+                 */
+                if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
+                        __hugetlb_cgroup_file_init(hstate_index(h));
+        }
 }
 
 /*