[SCSI] zfcp: Do not wait for SBALs on stopped queue

Trying to read the FC host statistics on an offline adapter results in
a 5 seconds wait. Reading the statistics tries to issue an exchange
port data request which first waits up to 5 seconds for an entry in
the request queue.

Change the strategy for getting a free SBAL to exit when the queue is
stopped. Reading the statistics will then fail without the wait.
Reviewed-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/s390/scsi/zfcp_fsf.c

@@ -719,11 +719,6 @@ static struct zfcp_fsf_req *zfcp_fsf_req_create(struct zfcp_qdio *qdio,
 	zfcp_qdio_req_init(adapter->qdio, &req->qdio_req, req->req_id, sbtype,
 			   req->qtcb, sizeof(struct fsf_qtcb));
 
-	if (!(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)) {
-		zfcp_fsf_req_free(req);
-		return ERR_PTR(-EIO);
-	}
-
 	return req;
 }
 

drivers/s390/scsi/zfcp_qdio.c

@@ -251,7 +251,8 @@ static int zfcp_qdio_sbal_check(struct zfcp_qdio *qdio)
 	struct zfcp_qdio_queue *req_q = &qdio->req_q;
 
 	spin_lock_bh(&qdio->req_q_lock);
-	if (atomic_read(&req_q->count))
+	if (atomic_read(&req_q->count) ||
+	    !(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
 		return 1;
 	spin_unlock_bh(&qdio->req_q_lock);
 	return 0;
@@ -274,8 +275,13 @@ int zfcp_qdio_sbal_get(struct zfcp_qdio *qdio)
 	spin_unlock_bh(&qdio->req_q_lock);
 	ret = wait_event_interruptible_timeout(qdio->req_q_wq,
 			       zfcp_qdio_sbal_check(qdio), 5 * HZ);
+
+	if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
+		return -EIO;
+
 	if (ret > 0)
 		return 0;
+
 	if (!ret) {
 		atomic_inc(&qdio->req_q_full);
 		/* assume hanging outbound queue, try queue recovery */
@@ -375,6 +381,8 @@ void zfcp_qdio_close(struct zfcp_qdio *qdio)
 	atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
 	spin_unlock_bh(&qdio->req_q_lock);
 
+	wake_up(&qdio->req_q_wq);
+
 	qdio_shutdown(qdio->adapter->ccw_device,
 		      QDIO_FLAG_CLEANUP_USING_CLEAR);