cifs: Use kmemdup rather than duplicating its implementation in smb311_posix_mkdir()

Use kmemdup rather than duplicating its implementation
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2pdu.c

@@ -2474,13 +2474,13 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 		goto ioctl_exit;
 	}
 
-	*out_data = kmalloc(*plen, GFP_KERNEL);
+	*out_data = kmemdup((char *)rsp + le32_to_cpu(rsp->OutputOffset),
+			    *plen, GFP_KERNEL);
 	if (*out_data == NULL) {
 		rc = -ENOMEM;
 		goto ioctl_exit;
 	}
 
-	memcpy(*out_data, (char *)rsp + le32_to_cpu(rsp->OutputOffset), *plen);
 ioctl_exit:
 	free_rsp_buf(resp_buftype, rsp);
 	return rc;