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>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 41b320e..73b1521 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2277,7 +2277,7 @@
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);