NTFS: Use MAX_BUF_PER_PAGE instead of variable sized array allocation for

      better code generation and one less sparse warning in fs/ntfs/aops.c.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

2 files changed, 10 insertions, 6 deletions

diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index 788e3bd2528b..7f7eec58fee2 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -113,6 +113,8 @@ ToDo/Notes:
         - Update attribute definition handling.
         - Add NTFS_MAX_CLUSTER_SIZE and NTFS_MAX_PAGES_PER_CLUSTER constants.
         - Use NTFS_MAX_CLUSTER_SIZE in super.c instead of hard coding 0x10000.
+        - Use MAX_BUF_PER_PAGE instead of variable sized array allocation for
+          better code generation and one less sparse warning in fs/ntfs/aops.c.
 
 2.1.22 - Many bug and race fixes and error handling improvements.
 
diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
index 6241c4cfbe28..24c46c200337 100644
--- a/fs/ntfs/aops.c
+++ b/fs/ntfs/aops.c
@@ -825,17 +825,15 @@ static int ntfs_write_mst_block(struct page *page,
         ntfs_inode *ni = NTFS_I(vi);
         ntfs_volume *vol = ni->vol;
         u8 *kaddr;
-        unsigned char bh_size_bits = vi->i_blkbits;
-        unsigned int bh_size = 1 << bh_size_bits;
         unsigned int rec_size = ni->itype.index.block_size;
         ntfs_inode *locked_nis[PAGE_CACHE_SIZE / rec_size];
         struct buffer_head *bh, *head, *tbh, *rec_start_bh;
-        int max_bhs = PAGE_CACHE_SIZE / bh_size;
-        struct buffer_head *bhs[max_bhs];
+        struct buffer_head *bhs[MAX_BUF_PER_PAGE];
         runlist_element *rl;
-        int i, nr_locked_nis, nr_recs, nr_bhs, bhs_per_rec, err, err2;
-        unsigned rec_size_bits;
+        int i, nr_locked_nis, nr_recs, nr_bhs, max_bhs, bhs_per_rec, err, err2;
+        unsigned bh_size, rec_size_bits;
         BOOL sync, is_mft, page_is_dirty, rec_is_dirty;
+        unsigned char bh_size_bits;
 
         ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
                         "0x%lx.", vi->i_ino, ni->type, page->index);
@@ -850,7 +848,11 @@ static int ntfs_write_mst_block(struct page *page,
          */
         BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
                         (NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
+        bh_size_bits = vi->i_blkbits;
+        bh_size = 1 << bh_size_bits;
+        max_bhs = PAGE_CACHE_SIZE / bh_size;
         BUG_ON(!max_bhs);
+        BUG_ON(max_bhs > MAX_BUF_PER_PAGE);
 
         /* Were we called for sync purposes? */
         sync = (wbc->sync_mode == WB_SYNC_ALL);