commit ed6078f70335f158ca79790a0d0708ce558a6e9a
author David Sterba <dsterba@suse.cz> Thu Jun 05 01:59:57 2014 +0200
committer Chris Mason <clm@fb.com> Wed Sep 17 13:37:17 2014 -0700
tree 636322e2a1e25f7db9f5982204a8fa4bc1bf9cbf
parent 4e54b17ad67a2d0d59bda6edcf725dc5b281c253

btrfs: use DIV_ROUND_UP instead of open-coded variants

The form

  (value + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT

is equivalent to

  (value + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE

The rest is a simple subsitution, no difference in the generated
assembly code.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

fs/btrfs/compression.c

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 1daea0b..eeee138 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -91,8 +91,7 @@
 	u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
 
 	return sizeof(struct compressed_bio) +
-		((disk_size + root->sectorsize - 1) / root->sectorsize) *
-		csum_size;
+		(DIV_ROUND_UP(disk_size, root->sectorsize)) * csum_size;
 }
 
 static struct bio *compressed_bio_alloc(struct block_device *bdev,
@@ -615,8 +614,7 @@
 	cb->compress_type = extent_compress_type(bio_flags);
 	cb->orig_bio = bio;
 
-	nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) /
-				 PAGE_CACHE_SIZE;
+	nr_pages = DIV_ROUND_UP(compressed_len, PAGE_CACHE_SIZE);
 	cb->compressed_pages = kzalloc(sizeof(struct page *) * nr_pages,
 				       GFP_NOFS);
 	if (!cb->compressed_pages)
@@ -686,8 +684,8 @@
 							comp_bio, sums);
 				BUG_ON(ret); /* -ENOMEM */
 			}
-			sums += (comp_bio->bi_iter.bi_size +
-				 root->sectorsize - 1) / root->sectorsize;
+			sums += DIV_ROUND_UP(comp_bio->bi_iter.bi_size,
+					     root->sectorsize);
 
 			ret = btrfs_map_bio(root, READ, comp_bio,
 					    mirror_num, 0);