IB/ipoib: Restore MM behavior in case of tx_ring allocation failure

memalloc_noio_save modifies the behavior of MM, we must restore it after
we are done.

Fixes: d83187dd ("IB/IPoIB: Convert IPoIB to memalloc_noio_* calls")
Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/ulp/ipoib/ipoib_cm.c

@@ -1145,6 +1145,7 @@ static int ipoib_cm_tx_init(struct ipoib_cm_tx *p, u32 qpn,
 	noio_flag = memalloc_noio_save();
 	p->tx_ring = vzalloc(ipoib_sendq_size * sizeof(*p->tx_ring));
 	if (!p->tx_ring) {
+		memalloc_noio_restore(noio_flag);
 		ret = -ENOMEM;
 		goto err_tx;
 	}