fs: add i_blocksize()

commit 93407472a21b82f39c955ea7787e5bc7da100642 upstream.

Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs
branch.

This patch also fixes multiple checkpatch warnings: WARNING: Prefer
'unsigned int' to bare use of 'unsigned'

Thanks to Andrew Morton for suggesting more appropriate function instead
of macro.

[geliangtang@gmail.com: truncate: use i_blocksize()]
  Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com
Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/truncate.c b/mm/truncate.c
index 8d8c62d..9c809e7 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -753,7 +753,7 @@ EXPORT_SYMBOL(truncate_setsize);
  */
 void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
 {
-	int bsize = 1 << inode->i_blkbits;
+	int bsize = i_blocksize(inode);
 	loff_t rounded_from;
 	struct page *page;
 	pgoff_t index;