hugetlbfs: New huge_add_to_page_cache helper routine

Currently, there is only a single place where hugetlbfs pages are added
to the page cache.  The new fallocate code be adding a second one, so
break the functionality out into its own helper.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 9 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 114ad6ce7030..d45eacc5653e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3375,6 +3375,23 @@ static bool hugetlbfs_pagecache_present(struct hstate *h,
         return page != NULL;
 }
 
+int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
+                           pgoff_t idx)
+{
+        struct inode *inode = mapping->host;
+        struct hstate *h = hstate_inode(inode);
+        int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
+
+        if (err)
+                return err;
+        ClearPagePrivate(page);
+
+        spin_lock(&inode->i_lock);
+        inode->i_blocks += blocks_per_huge_page(h);
+        spin_unlock(&inode->i_lock);
+        return 0;
+}
+
 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
                            struct address_space *mapping, pgoff_t idx,
                            unsigned long address, pte_t *ptep, unsigned int flags)
@@ -3422,21 +3439,13 @@ retry:
                 set_page_huge_active(page);
 
                 if (vma->vm_flags & VM_MAYSHARE) {
-                        int err;
-                        struct inode *inode = mapping->host;
-
-                        err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
+                        int err = huge_add_to_page_cache(page, mapping, idx);
                         if (err) {
                                 put_page(page);
                                 if (err == -EEXIST)
                                         goto retry;
                                 goto out;
                         }
-                        ClearPagePrivate(page);
-
-                        spin_lock(&inode->i_lock);
-                        inode->i_blocks += blocks_per_huge_page(h);
-                        spin_unlock(&inode->i_lock);
                 } else {
                         lock_page(page);
                         if (unlikely(anon_vma_prepare(vma))) {