Ext3: use unlikely to improve the efficiency of the kernel

Because the function 'sb_getblk' seldomly fails to return
NULL value,it will be better to use unlikely to check it.

Signed-off-by: Wang Shilong <[e-mail]>
Signed-off-by: Jan Kara <[e-mail]>

fs/ext3/inode.c

···
 	if (!err && buffer_mapped(&dummy)) {
 		struct buffer_head *bh;
 		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
-		if (!bh) {
+		if (unlikely(!bh)) {
 			*errp = -EIO;
 			goto err;
 		}
···
 		return -EIO;
 
 	bh = sb_getblk(inode->i_sb, block);
-	if (!bh) {
+	if (unlikely(!bh)) {
 		ext3_error (inode->i_sb, "ext3_get_inode_loc",
 				"unable to read inode block - "
 				"inode=%lu, block="E3FSBLK,
···
 
 			bitmap_bh = sb_getblk(inode->i_sb,
 					le32_to_cpu(desc->bg_inode_bitmap));
-			if (!bitmap_bh)
+			if (unlikely(!bitmap_bh))
 				goto make_io;
 
 			/*

fs/ext3/resize.c

···
 	int err;
 
 	bh = sb_getblk(sb, blk);
-	if (!bh)
+	if (unlikely(!bh))
 		return ERR_PTR(-EIO);
 	if ((err = ext3_journal_get_write_access(handle, bh))) {
 		brelse(bh);
···
 			goto exit_bh;
 
 		gdb = sb_getblk(sb, block);
-		if (!gdb) {
+		if (unlikely(!gdb)) {
 			err = -EIO;
 			goto exit_bh;
 		}
···
 			break;
 
 		bh = sb_getblk(sb, group * bpg + blk_off);
-		if (!bh) {
+		if (unlikely(!bh)) {
 			err = -EIO;
 			break;
 		}

fs/ext3/xattr.c

···
 			ea_idebug(inode, "creating block %d", block);
 
 			new_bh = sb_getblk(sb, block);
-			if (!new_bh) {
+			if (unlikely(!new_bh)) {
 getblk_failed:
 				ext3_free_blocks(handle, inode, block, 1);
 				error = -EIO;