[SCSI] zfcp: Increase ref counter for port open requests

In rare cases, open port request might timeout, erp calls
zfcp_port_put, port gets dequeued. Now, the late returning (or
dismissed) fsf-port-open calls the fsf_port_open_handler that tries to
reference the port data structure leading to a kernel oops.

Signed-off-by: Martin Petermann <martin.petermann@de.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index b550c249389d9b7e40f84fcbec3ec0c70a2dbd7a..6fae2688fede8af422f9e2accd39d2c0aae2f0d1 100644 (file)
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -1402,7 +1402,7 @@ static void zfcp_fsf_open_port_handler(struct zfcp_fsf_req *req)
        struct fsf_plogi *plogi;
 
        if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
-               return;
+               goto out;
 
        switch (header->fsf_status) {
        case FSF_PORT_ALREADY_OPEN:
@@ -1464,6 +1464,9 @@ static void zfcp_fsf_open_port_handler(struct zfcp_fsf_req *req)
                req->status |= ZFCP_STATUS_FSFREQ_ERROR;
                break;
        }
+
+out:
+       zfcp_port_put(port);
 }
 
 /**
@@ -1476,6 +1479,7 @@ int zfcp_fsf_open_port(struct zfcp_erp_action *erp_action)
        struct qdio_buffer_element *sbale;
        struct zfcp_adapter *adapter = erp_action->adapter;
        struct zfcp_fsf_req *req;
+       struct zfcp_port *port = erp_action->port;
        int retval = -EIO;
 
        spin_lock_bh(&adapter->req_q_lock);
@@ -1496,16 +1500,18 @@ int zfcp_fsf_open_port(struct zfcp_erp_action *erp_action)
         sbale[1].flags |= SBAL_FLAGS_LAST_ENTRY;
 
        req->handler = zfcp_fsf_open_port_handler;
-       req->qtcb->bottom.support.d_id = erp_action->port->d_id;
-       req->data = erp_action->port;
+       req->qtcb->bottom.support.d_id = port->d_id;
+       req->data = port;
        req->erp_action = erp_action;
        erp_action->fsf_req = req;
+       zfcp_port_get(port);
 
        zfcp_fsf_start_erp_timer(req);
        retval = zfcp_fsf_req_send(req);
        if (retval) {
                zfcp_fsf_req_free(req);
                erp_action->fsf_req = NULL;
+               zfcp_port_put(port);
        }
 out:
        spin_unlock_bh(&adapter->req_q_lock);