ext4: consolidate in_range() definitions

There are duplicate macro definitions of in_range() in mballoc.h and
balloc.c.  This consolidates these two definitions into ext4.h, and
changes extents.c to use in_range() as well.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger@sun.com>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 3c0bae1..94c8ee8 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2051,7 +2051,7 @@
 
 	BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
 			cex->ec_type != EXT4_EXT_CACHE_EXTENT);
-	if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
+	if (in_range(block, cex->ec_block, cex->ec_len)) {
 		ex->ee_block = cpu_to_le32(cex->ec_block);
 		ext4_ext_store_pblock(ex, cex->ec_start);
 		ex->ee_len = cpu_to_le16(cex->ec_len);
@@ -3364,7 +3364,7 @@
 		 */
 		ee_len = ext4_ext_get_actual_len(ex);
 		/* if found extent covers block, simply return it */
-		if (iblock >= ee_block && iblock < ee_block + ee_len) {
+		if (in_range(iblock, ee_block, ee_len)) {
 			newblock = iblock - ee_block + ee_start;
 			/* number of remaining blocks in the extent */
 			allocated = ee_len - (iblock - ee_block);