[SCSI] zfcp: Make queue_depth adjustable
zfcp did always set the queue_depth for SCSI devices to 32, not
allowing to change this. Introduce a kernel parameter zfcp.queue_depth
and the change_queue_depth callback to allow changing the queue_depth
when it is required.
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@HansenPartnership.com>
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index e8fbeae..7d0da23 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -12,6 +12,10 @@
#include "zfcp_ext.h"
#include <asm/atomic.h>
+static unsigned int default_depth = 32;
+module_param_named(queue_depth, default_depth, uint, 0600);
+MODULE_PARM_DESC(queue_depth, "Default queue depth for new SCSI devices");
+
/* Find start of Sense Information in FCP response unit*/
char *zfcp_get_fcp_sns_info_ptr(struct fcp_rsp_iu *fcp_rsp_iu)
{
@@ -24,6 +28,12 @@
return fcp_sns_info_ptr;
}
+static int zfcp_scsi_change_queue_depth(struct scsi_device *sdev, int depth)
+{
+ scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
+ return sdev->queue_depth;
+}
+
static void zfcp_scsi_slave_destroy(struct scsi_device *sdpnt)
{
struct zfcp_unit *unit = (struct zfcp_unit *) sdpnt->hostdata;
@@ -34,7 +44,7 @@
static int zfcp_scsi_slave_configure(struct scsi_device *sdp)
{
if (sdp->tagged_supported)
- scsi_adjust_queue_depth(sdp, MSG_SIMPLE_TAG, 32);
+ scsi_adjust_queue_depth(sdp, MSG_SIMPLE_TAG, default_depth);
else
scsi_adjust_queue_depth(sdp, 0, 1);
return 0;
@@ -647,6 +657,7 @@
.name = "zfcp",
.module = THIS_MODULE,
.proc_name = "zfcp",
+ .change_queue_depth = zfcp_scsi_change_queue_depth,
.slave_alloc = zfcp_scsi_slave_alloc,
.slave_configure = zfcp_scsi_slave_configure,
.slave_destroy = zfcp_scsi_slave_destroy,