net/mlx4_core: Limit count field to 24 bits in qp_alloc_res

commit 2d5c57d7 upstream.

Some VF drivers use the upper byte of "param1" (the qp count field)
in mlx4_qp_reserve_range() to pass flags which are used to optimize
the range allocation.

Under the current code, if any of these flags are set, the 32-bit
count field yields a count greater than 2^24, which is out of range,
and this VF fails.

As these flags represent a "best-effort" allocation hint anyway, they may
safely be ignored. Therefore, the PF driver may simply mask out the bits.

Fixes: c82e9aa0 "mlx4_core: resource tracking for HCA resources used by guests"
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c

@@ -1532,7 +1532,7 @@ static int qp_alloc_res(struct mlx4_dev *dev, int slave, int op, int cmd,
 
 	switch (op) {
 	case RES_OP_RESERVE:
-		count = get_param_l(&in_param);
+		count = get_param_l(&in_param) & 0xffffff;
 		align = get_param_h(&in_param);
 		err = mlx4_grant_resource(dev, slave, RES_QP, count, 0);
 		if (err)