mm, hugetlb: clean-up alloc_huge_page()

Unify successful allocation paths to make the code more readable.  There
are no functional changes.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

@@ -1166,12 +1166,7 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
 	}
 	spin_lock(&hugetlb_lock);
 	page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
-	if (page) {
-		/* update page cgroup details */
-		hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h),
-					     h_cg, page);
-		spin_unlock(&hugetlb_lock);
-	} else {
+	if (!page) {
 		spin_unlock(&hugetlb_lock);
 		page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
 		if (!page) {
@@ -1182,11 +1177,11 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
 			return ERR_PTR(-ENOSPC);
 		}
 		spin_lock(&hugetlb_lock);
-		hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h),
-					     h_cg, page);
 		list_move(&page->lru, &h->hugepage_activelist);
-		spin_unlock(&hugetlb_lock);
+		/* Fall through */
 	}
+	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
+	spin_unlock(&hugetlb_lock);
 
 	set_page_private(page, (unsigned long)spool);