jfs: Fix do_div precision in commit b40c2e66

In a hasty fix to replace a 64-bit division with do_div, I
unintentionally assigned the divisor to a 32-bit variable.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: Tino Reichardt <milky-kernel@mcmilk.de>

1 files changed, 4 insertions, 3 deletions

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 174feb6a73c1..9a55f53be5ff 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -1641,14 +1641,15 @@ s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
 
         /* max blkno / nblocks pairs to trim */
         int count = 0, range_cnt;
+        u64 max_ranges;
 
         /* prevent others from writing new stuff here, while trimming */
         IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
 
         nblocks = bmp->db_agfree[agno];
-        range_cnt = nblocks;
-        do_div(range_cnt, (int)minlen);
-        range_cnt = min(range_cnt + 1, 32 * 1024);
+        max_ranges = nblocks;
+        do_div(max_ranges, minlen);
+        range_cnt = min_t(u64, max_ranges + 1, 32 * 1024);
         totrim = kmalloc(sizeof(struct range2trim) * range_cnt, GFP_NOFS);
         if (totrim == NULL) {
                 jfs_error(bmp->db_ipbmap->i_sb,