scsi: libsas: fix memory leak in sas_smp_get_phy_events()

We've got a memory leak with the following producer:

while true;
do cat /sys/class/sas_phy/phy-1:0:12/invalid_dword_count >/dev/null;
done

The buffer req is allocated and not freed after we return. Fix it.

Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver")
Signed-off-by: Jason Yan <yanaijie@huawei.com>
CC: John Garry <john.garry@huawei.com>
CC: chenqilin <chenqilin2@huawei.com>
CC: chenxiang <chenxiang66@hisilicon.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
static int sas_check_eeds(struct domain_device *child,
				 struct ex_phy *parent_phy,
				 struct ex_phy *child_phy)
{
	int res = 0;
	struct domain_device *parent = child->parent;

	if (SAS_ADDR(parent->port->disc.fanout_sas_addr) != 0) {
		res = -ENODEV;
		SAS_DPRINTK("edge ex %016llx phy S:0x%x <--> edge ex %016llx "
			    "phy S:0x%x, while there is a fanout ex %016llx\n",
			    SAS_ADDR(parent->sas_addr),
			    parent_phy->phy_id,
			    SAS_ADDR(child->sas_addr),
			    child_phy->phy_id,
			    SAS_ADDR(parent->port->disc.fanout_sas_addr));
	} else if (SAS_ADDR(parent->port->disc.eeds_a) == 0) {
		memcpy(parent->port->disc.eeds_a, parent->sas_addr,
		       SAS_ADDR_SIZE);
		memcpy(parent->port->disc.eeds_b, child->sas_addr,
		       SAS_ADDR_SIZE);
	} else if (((SAS_ADDR(parent->port->disc.eeds_a) ==
		    SAS_ADDR(parent->sas_addr)) ||
		   (SAS_ADDR(parent->port->disc.eeds_a) ==
		    SAS_ADDR(child->sas_addr)))
		   &&
		   ((SAS_ADDR(parent->port->disc.eeds_b) ==
		     SAS_ADDR(parent->sas_addr)) ||
		    (SAS_ADDR(parent->port->disc.eeds_b) ==
		     SAS_ADDR(child->sas_addr))))
		;
	else {
		res = -ENODEV;
		SAS_DPRINTK("edge ex %016llx phy 0x%x <--> edge ex %016llx "
			    "phy 0x%x link forms a third EEDS!\n",
			    SAS_ADDR(parent->sas_addr),
			    parent_phy->phy_id,
			    SAS_ADDR(child->sas_addr),
			    child_phy->phy_id);
	}

	return res;
}

static int sas_check_eeds(struct domain_device *child,
				 struct ex_phy *parent_phy,
				 struct ex_phy *child_phy)
{
	int res = 0;
	struct domain_device *parent = child->parent;

	if (SAS_ADDR(parent->port->disc.fanout_sas_addr) != 0) {
		res = -ENODEV;
		SAS_DPRINTK("edge ex %016llx phy S:0x%x <--> edge ex %016llx "
			    "phy S:0x%x, while there is a fanout ex %016llx\n",
			    SAS_ADDR(parent->sas_addr),
			    parent_phy->phy_id,
			    SAS_ADDR(child->sas_addr),
			    child_phy->phy_id,
			    SAS_ADDR(parent->port->disc.fanout_sas_addr));
	} else if (SAS_ADDR(parent->port->disc.eeds_a) == 0) {
		memcpy(parent->port->disc.eeds_a, parent->sas_addr,
		       SAS_ADDR_SIZE);
		memcpy(parent->port->disc.eeds_b, child->sas_addr,
		       SAS_ADDR_SIZE);
	} else if (((SAS_ADDR(parent->port->disc.eeds_a) ==
		    SAS_ADDR(parent->sas_addr)) ||
		   (SAS_ADDR(parent->port->disc.eeds_a) ==
		    SAS_ADDR(child->sas_addr)))
		   &&
		   ((SAS_ADDR(parent->port->disc.eeds_b) ==
		     SAS_ADDR(parent->sas_addr)) ||
		    (SAS_ADDR(parent->port->disc.eeds_b) ==
		     SAS_ADDR(child->sas_addr))))
		;
	else {
		res = -ENODEV;
		SAS_DPRINTK("edge ex %016llx phy 0x%x <--> edge ex %016llx "
			    "phy 0x%x link forms a third EEDS!\n",
			    SAS_ADDR(parent->sas_addr),
			    parent_phy->phy_id,
			    SAS_ADDR(child->sas_addr),
			    child_phy->phy_id);
	}

	return res;
}
