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>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 033f04b..2287545 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1481,9 +1481,8 @@
bool force_page_uptodate = false;
bool need_unlock;
- nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
- PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
- (sizeof(struct page *)));
+ nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_CACHE_SIZE),
+ PAGE_CACHE_SIZE / (sizeof(struct page *)));
nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
nrptrs = max(nrptrs, 8);
pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
@@ -1497,8 +1496,8 @@
size_t write_bytes = min(iov_iter_count(i),
nrptrs * (size_t)PAGE_CACHE_SIZE -
offset);
- size_t num_pages = (write_bytes + offset +
- PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ size_t num_pages = DIV_ROUND_UP(write_bytes + offset,
+ PAGE_CACHE_SIZE);
size_t reserve_bytes;
size_t dirty_pages;
size_t copied;
@@ -1526,9 +1525,8 @@
* our prealloc extent may be smaller than
* write_bytes, so scale down.
*/
- num_pages = (write_bytes + offset +
- PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
+ num_pages = DIV_ROUND_UP(write_bytes + offset,
+ PAGE_CACHE_SIZE);
reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
ret = 0;
} else {
@@ -1590,9 +1588,8 @@
dirty_pages = 0;
} else {
force_page_uptodate = false;
- dirty_pages = (copied + offset +
- PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
+ dirty_pages = DIV_ROUND_UP(copied + offset,
+ PAGE_CACHE_SIZE);
}
/*