[SCSI] zfcp: receiving an unsolicted status can lead to I/O stall

Processing of an unsolicted status request can lead to a locking race
of the request_queue's queue_lock during the recreation of the
used up status read request while still in interrupt context
of the response handler.

Detaching the 'refill' of the long running status read requests from
the handler to a scheduled work is solving this issue.

In addition, each refill-run is trying to re-establish the full amount
of status read requests, which might have failed in earlier runs.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 2 insertions, 17 deletions

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index 805484658dd..55a4fdc4262 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -2139,25 +2139,10 @@ static int
 zfcp_erp_adapter_strategy_open_fsf_statusread(struct zfcp_erp_action
                                               *erp_action)
 {
-        int retval = ZFCP_ERP_SUCCEEDED;
-        int temp_ret;
         struct zfcp_adapter *adapter = erp_action->adapter;
-        int i;
 
-        adapter->status_read_failed = 0;
-        for (i = 0; i < ZFCP_STATUS_READS_RECOM; i++) {
-                temp_ret = zfcp_fsf_status_read(adapter, ZFCP_WAIT_FOR_SBAL);
-                if (temp_ret < 0) {
-                        ZFCP_LOG_INFO("error: set-up of unsolicited status "
-                                      "notification failed on adapter %s\n",
-                                      zfcp_get_busid_by_adapter(adapter));
-                        retval = ZFCP_ERP_FAILED;
-                        i--;
-                        break;
-                }
-        }
-
-        return retval;
+        atomic_set(&adapter->stat_miss, 16);
+        return zfcp_status_read_refill(adapter);
 }
 
 /*