[SCSI] zfcp: Hold queue lock when checking port/unit handle for FCP command

We need to hold the queue-lock when checking whether we still have a valid
unit/port handle for the FCP command, i.e whether we can issue this request for
this unit/port. If the error recovery is about to close this unit/port, then it
competes for the queue-lock. If the close request issued by the error recovery
wins, then it is guaranteed that this unit/port has been blocked for other
requests.

Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Martin Peschke <mp3@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

2 files changed, 10 insertions, 5 deletions

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 908e8b2107c1..17c251cb10aa 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -3593,6 +3593,12 @@ zfcp_fsf_send_fcp_command_task(struct zfcp_adapter *adapter,
                 goto failed_req_create;
         }
 
+        if (unlikely(!atomic_test_mask(ZFCP_STATUS_COMMON_UNBLOCKED,
+                        &unit->status))) {
+                retval = -EBUSY;
+                goto unit_blocked;
+        }
+
         zfcp_unit_get(unit);
         fsf_req->unit = unit;
 
@@ -3733,6 +3739,7 @@ zfcp_fsf_send_fcp_command_task(struct zfcp_adapter *adapter,
  send_failed:
  no_fit:
  failed_scsi_cmnd:
+ unit_blocked:
         zfcp_unit_put(unit);
         zfcp_fsf_req_free(fsf_req);
         fsf_req = NULL;
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 3298fd35000c..b9daf5c05862 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -258,8 +258,9 @@ zfcp_scsi_command_async(struct zfcp_adapter *adapter, struct zfcp_unit *unit,
                 goto out;
         }
 
-        if (unlikely(
-             !atomic_test_mask(ZFCP_STATUS_COMMON_UNBLOCKED, &unit->status))) {
+        tmp = zfcp_fsf_send_fcp_command_task(adapter, unit, scpnt, use_timer,
+                                             ZFCP_REQ_AUTO_CLEANUP);
+        if (unlikely(tmp == -EBUSY)) {
                 ZFCP_LOG_DEBUG("adapter %s not ready or unit 0x%016Lx "
                                "on port 0x%016Lx in recovery\n",
                                zfcp_get_busid_by_unit(unit),
@@ -268,9 +269,6 @@ zfcp_scsi_command_async(struct zfcp_adapter *adapter, struct zfcp_unit *unit,
                 goto out;
         }
 
-        tmp = zfcp_fsf_send_fcp_command_task(adapter, unit, scpnt, use_timer,
-                                             ZFCP_REQ_AUTO_CLEANUP);
-
         if (unlikely(tmp < 0)) {
                 ZFCP_LOG_DEBUG("error: initiation of Send FCP Cmnd failed\n");
                 retval = SCSI_MLQUEUE_HOST_BUSY;