btrfs: cleanup 64bit/32bit divs, compile time constants

Switch to div_u64 if the divisor is a numeric constant or sum of
sizeof()s. We can remove a few instances of do_div that has the hidden
semtantics of changing the 1st argument.

Small power-of-two divisors are converted to bitshifts, large values are
kept intact for clarity.

Signed-off-by: David Sterba <dsterba@suse.cz>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 41b320e235d7..73b152138221 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2277,7 +2277,7 @@ int open_ctree(struct super_block *sb,
         fs_info->free_chunk_space = 0;
         fs_info->tree_mod_log = RB_ROOT;
         fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
-        fs_info->avg_delayed_ref_runtime = div64_u64(NSEC_PER_SEC, 64);
+        fs_info->avg_delayed_ref_runtime = NSEC_PER_SEC >> 6; /* div by 64 */
         /* readahead state */
         INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
         spin_lock_init(&fs_info->reada_lock);