[SCSI] zfcp: Send ELS ADISC from workqueue

Issue ELS ADISC requests from workqueue. This allows the link test
request to be sent when the request queue is full due to I/O load for
other remote ports. It also simplifies request queue locking,
zfcp_fsf_send_fcp_command_task is now the only function that has
interrupts disabled from the caller. This is also a prereq for the FC
passthrough support that issues ELS requests from userspace.

Acked-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, 18 insertions, 10 deletions

diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c
index 67e6b71..0f435ed 100644
--- a/drivers/s390/scsi/zfcp_fc.c
+++ b/drivers/s390/scsi/zfcp_fc.c
@@ -421,19 +421,12 @@ static int zfcp_fc_adisc(struct zfcp_port *port)
 	return zfcp_fsf_send_els(&adisc->els);
 }
 
-/**
- * zfcp_test_link - lightweight link test procedure
- * @port: port to be tested
- *
- * Test status of a link to a remote port using the ELS command ADISC.
- * If there is a problem with the remote port, error recovery steps
- * will be triggered.
- */
-void zfcp_test_link(struct zfcp_port *port)
+void zfcp_fc_link_test_work(struct work_struct *work)
 {
+	struct zfcp_port *port =
+		container_of(work, struct zfcp_port, test_link_work);
 	int retval;
 
-	zfcp_port_get(port);
 	retval = zfcp_fc_adisc(port);
 	if (retval == 0)
 		return;
@@ -444,6 +437,21 @@ void zfcp_test_link(struct zfcp_port *port)
 		zfcp_erp_port_forced_reopen(port, 0, 65, NULL);
 }
 
+/**
+ * zfcp_test_link - lightweight link test procedure
+ * @port: port to be tested
+ *
+ * Test status of a link to a remote port using the ELS command ADISC.
+ * If there is a problem with the remote port, error recovery steps
+ * will be triggered.
+ */
+void zfcp_test_link(struct zfcp_port *port)
+{
+	zfcp_port_get(port);
+	if (!queue_work(zfcp_data.work_queue, &port->test_link_work))
+		zfcp_port_put(port);
+}
+
 static void zfcp_free_sg_env(struct zfcp_gpn_ft *gpn_ft, int buf_num)
 {
 	struct scatterlist *sg = &gpn_ft->sg_req;