What is the religious ruling regarding a person donating to build a mosque and then dedicating a part of it for a kindergarten from which the donor benefits?

If you donate a plot of land as a mosque, and then add to it, the entire additional area becomes part of the mosque, and nothing may be taken from it for purposes other than the mosque's benefit. The fact that the registered area with the Awqaf (Endowments) Ministry is less does not affect this; once a mosque is built and permission is given for prayer in it, it becomes an endowment, liberated from anyone having ownership over it.