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, 4 insertions, 4 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 96611fed552f..cb84923561e4 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1537,7 +1537,7 @@ static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
         else
                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
-                        div64_u64(size, 1024 * 1024 * 1024);
+                        div_u64(size, 1024 * 1024 * 1024);
 
         /*
          * we want to account for 1 more bitmap than what we have so we can make
@@ -1552,14 +1552,14 @@ static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
         }
 
         /*
-         * we want the extent entry threshold to always be at most 1/2 the maxw
+         * we want the extent entry threshold to always be at most 1/2 the max
          * bytes we can have, or whatever is less than that.
          */
         extent_bytes = max_bytes - bitmap_bytes;
-        extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
+        extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
 
         ctl->extents_thresh =
-                div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
+                div_u64(extent_bytes, sizeof(struct btrfs_free_space));
 }
 
 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,