[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_def.h b/drivers/s390/scsi/zfcp_def.h
index 5bc4afba..1305955 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -205,6 +205,7 @@
struct zfcp_adapter *adapter; /* adapter used to access port */
struct list_head unit_list; /* head of logical unit list */
rwlock_t unit_list_lock; /* unit list lock */
+ atomic_t units; /* zfcp_unit count */
atomic_t status; /* status of this remote port */
u64 wwnn; /* WWNN if known */
u64 wwpn; /* WWPN */