[SCSI] zfcp: restore refcount check on port_remove
Upstream commit f3450c7b917201bb49d67032e9f60d5125675d6a
"[SCSI] zfcp: Replace local reference counting with common kref"
accidentally dropped a reference count check before tearing down
zfcp_ports that are potentially in use by zfcp_units.
Even remote ports in use can be removed causing
unreachable garbage objects zfcp_ports with zfcp_units.
Thus units won't come back even after a manual port_rescan.
The kref of zfcp_port->dev.kobj is already used by the driver core.
We cannot re-use it to track the number of zfcp_units.
Re-introduce our own counter for units per port
and check on port_remove.
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@vger.kernel.org> #2.6.33+
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/s390/scsi/zfcp_unit.c b/drivers/s390/scsi/zfcp_unit.c
index 3f2bff0..1cd2b99 100644
--- a/drivers/s390/scsi/zfcp_unit.c
+++ b/drivers/s390/scsi/zfcp_unit.c
@@ -104,7 +104,7 @@
{
struct zfcp_unit *unit = container_of(dev, struct zfcp_unit, dev);
- put_device(&unit->port->dev);
+ atomic_dec(&unit->port->units);
kfree(unit);
}
@@ -119,16 +119,27 @@
int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
{
struct zfcp_unit *unit;
+ int retval = 0;
+
+ mutex_lock(&zfcp_sysfs_port_units_mutex);
+ if (atomic_read(&port->units) == -1) {
+ /* port is already gone */
+ retval = -ENODEV;
+ goto out;
+ }
unit = zfcp_unit_find(port, fcp_lun);
if (unit) {
put_device(&unit->dev);
- return -EEXIST;
+ retval = -EEXIST;
+ goto out;
}
unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
- if (!unit)
- return -ENOMEM;
+ if (!unit) {
+ retval = -ENOMEM;
+ goto out;
+ }
unit->port = port;
unit->fcp_lun = fcp_lun;
@@ -139,28 +150,33 @@
if (dev_set_name(&unit->dev, "0x%016llx",
(unsigned long long) fcp_lun)) {
kfree(unit);
- return -ENOMEM;
+ retval = -ENOMEM;
+ goto out;
}
- get_device(&port->dev);
-
if (device_register(&unit->dev)) {
put_device(&unit->dev);
- return -ENOMEM;
+ retval = -ENOMEM;
+ goto out;
}
if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs)) {
device_unregister(&unit->dev);
- return -EINVAL;
+ retval = -EINVAL;
+ goto out;
}
+ atomic_inc(&port->units); /* under zfcp_sysfs_port_units_mutex ! */
+
write_lock_irq(&port->unit_list_lock);
list_add_tail(&unit->list, &port->unit_list);
write_unlock_irq(&port->unit_list_lock);
zfcp_unit_scsi_scan(unit);
- return 0;
+out:
+ mutex_unlock(&zfcp_sysfs_port_units_mutex);
+ return retval;
}
/**