[SCSI] zfcp: fix race conditions when accessing erp_action lists

o always use locking when changing erp_action lists,
o avoid escalation to ERP_ACTION_REOPEN_PORT_FORCED if erp_action is
  still in use for ERP_ACTION_REOPEN_PORT

Signed-off-by: Andreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 17 insertions, 7 deletions

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index cb4f612550ba..376cb0f6cb74 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -886,7 +886,7 @@ static int
 zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *erp_action)
 {
         int retval = 0;
-        struct zfcp_fsf_req *fsf_req;
+        struct zfcp_fsf_req *fsf_req = NULL;
         struct zfcp_adapter *adapter = erp_action->adapter;
 
         if (erp_action->fsf_req) {
@@ -896,7 +896,7 @@ zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *erp_action)
                 list_for_each_entry(fsf_req, &adapter->fsf_req_list_head, list)
                     if (fsf_req == erp_action->fsf_req)
                         break;
-                if (fsf_req == erp_action->fsf_req) {
+                if (fsf_req && (fsf_req->erp_action == erp_action)) {
                         /* fsf_req still exists */
                         debug_text_event(adapter->erp_dbf, 3, "a_ca_req");
                         debug_event(adapter->erp_dbf, 3, &fsf_req,
@@ -2291,7 +2291,9 @@ zfcp_erp_adapter_strategy_open_fsf_xconfig(struct zfcp_erp_action *erp_action)
                 atomic_clear_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
                                   &adapter->status);
                 ZFCP_LOG_DEBUG("Doing exchange config data\n");
+                write_lock(&adapter->erp_lock);
                 zfcp_erp_action_to_running(erp_action);
+                write_unlock(&adapter->erp_lock);
                 zfcp_erp_timeout_init(erp_action);
                 if (zfcp_fsf_exchange_config_data(erp_action)) {
                         retval = ZFCP_ERP_FAILED;
@@ -3194,11 +3196,19 @@ zfcp_erp_action_enqueue(int action,
                 /* fall through !!! */
 
         case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
-                if (atomic_test_mask
-                    (ZFCP_STATUS_COMMON_ERP_INUSE, &port->status)
-                    && port->erp_action.action ==
-                    ZFCP_ERP_ACTION_REOPEN_PORT_FORCED) {
-                        debug_text_event(adapter->erp_dbf, 4, "pf_actenq_drp");
+                if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_INUSE,
+                                     &port->status)) {
+                        if (port->erp_action.action !=
+                            ZFCP_ERP_ACTION_REOPEN_PORT_FORCED) {
+                                ZFCP_LOG_INFO("dropped erp action %i (port "
+                                              "0x%016Lx, action in use: %i)\n",
+                                              action, port->wwpn,
+                                              port->erp_action.action);
+                                debug_text_event(adapter->erp_dbf, 4,
+                                                 "pf_actenq_drp");
+                        } else 
+                                debug_text_event(adapter->erp_dbf, 4,
+                                                 "pf_actenq_drpcp");
                         debug_event(adapter->erp_dbf, 4, &port->wwpn,
                                     sizeof (wwn_t));
                         goto out;