mm: remove unnecessary condition in remove_inode_hugepages

When the huge page is added to the page cahce (huge_add_to_page_cache),
the page private flag will be cleared.  since this code
(remove_inode_hugepages) will only be called for pages in the page
cahce, PagePrivate(page) will always be false.

The patch remove the code without any functional change.

Link: http://lkml.kernel.org/r/1475113323-29368-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hugetlbfs/inode.c

@@ -416,7 +416,6 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 
 		for (i = 0; i < pagevec_count(&pvec); ++i) {
 			struct page *page = pvec.pages[i];
-			bool rsv_on_error;
 			u32 hash;
 
 			/*
@@ -458,18 +457,17 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 			 * cache (remove_huge_page) BEFORE removing the
 			 * region/reserve map (hugetlb_unreserve_pages).  In
 			 * rare out of memory conditions, removal of the
-			 * region/reserve map could fail.  Before free'ing
-			 * the page, note PagePrivate which is used in case
-			 * of error.
+			 * region/reserve map could fail. Correspondingly,
+			 * the subpool and global reserve usage count can need
+			 * to be adjusted.
 			 */
-			rsv_on_error = !PagePrivate(page);
+			VM_BUG_ON(PagePrivate(page));
 			remove_huge_page(page);
 			freed++;
 			if (!truncate_op) {
 				if (unlikely(hugetlb_unreserve_pages(inode,
 							next, next + 1, 1)))
-					hugetlb_fix_reserve_counts(inode,
-								rsv_on_error);
+					hugetlb_fix_reserve_counts(inode);
 			}
 
 			unlock_page(page);

include/linux/hugetlb.h

@@ -90,7 +90,7 @@ int dequeue_hwpoisoned_huge_page(struct page *page);
 bool isolate_huge_page(struct page *page, struct list_head *list);
 void putback_active_hugepage(struct page *page);
 void free_huge_page(struct page *page);
-void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserve);
+void hugetlb_fix_reserve_counts(struct inode *inode);
 extern struct mutex *hugetlb_fault_mutex_table;
 u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
 				struct vm_area_struct *vma,

mm/hugetlb.c

@@ -567,13 +567,13 @@ static long region_del(struct resv_map *resv, long f, long t)
  * appear as a "reserved" entry instead of simply dangling with incorrect
  * counts.
  */
-void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserve)
+void hugetlb_fix_reserve_counts(struct inode *inode)
 {
 	struct hugepage_subpool *spool = subpool_inode(inode);
 	long rsv_adjust;
 
 	rsv_adjust = hugepage_subpool_get_pages(spool, 1);
-	if (restore_reserve && rsv_adjust) {
+	if (rsv_adjust) {
 		struct hstate *h = hstate_inode(inode);
 
 		hugetlb_acct_memory(h, 1);