[PATCH 14/16 v4] ibmvscsi: driver enablement for CMO

=46rom: Robert Jennings [off-list ref]

Enable the driver to function in a Cooperative Memory Overcommitment (CMO)
environment.

The following changes are made to enable the driver for CMO:
 * DMA mapping errors will not result in error messages if entitlement has
   been exceeded and resources were not available.
 * The driver has a get_desired_dma function defined to function
   in a CMO environment. It will indicate how much IO memory it would like
   to function.

Signed-off-by: Robert Jennings <redacted>
Acked by: Brian King [off-list ref]

---
We would like to take this patch through linuxppc-dev with the full
change set for this feature.  We are copying linux-scsi for review and ack.

---
 drivers/scsi/ibmvscsi/ibmvscsi.c |   45 +++++++++++++++++++++++++++++++++-=
-----
 drivers/scsi/ibmvscsi/ibmvscsi.h |    2 ++
 2 files changed, 40 insertions(+), 7 deletions(-)

Index: b/drivers/scsi/ibmvscsi/ibmvscsi.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c

@@ -72,6 +72,7 @@
 #include <linux/delay.h>
 #include <asm/firmware.h>
 #include <asm/vio.h>
+#include <asm/firmware.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_host.h>

@@ -426,8 +427,10 @@ static int map_sg_data(struct scsi_cmnd=20
 					   SG_ALL * sizeof(struct srp_direct_buf),
 					   &evt_struct->ext_list_token, 0);
 		if (!evt_struct->ext_list) {
-			sdev_printk(KERN_ERR, cmd->device,
-				    "Can't allocate memory for indirect table\n");
+			if (!firmware_has_feature(FW_FEATURE_CMO))
+				sdev_printk(KERN_ERR, cmd->device,
+				            "Can't allocate memory "
+				            "for indirect table\n");
 			return 0;
 		}
 	}

@@ -743,7 +746,9 @@ static int ibmvscsi_queuecommand(struct=20
 	srp_cmd->lun =3D ((u64) lun) << 48;

=20
 	if (!map_data_for_srp_cmd(cmnd, evt_struct, srp_cmd, hostdata->dev)) {
-		sdev_printk(KERN_ERR, cmnd->device, "couldn't convert cmd to srp_cmd\n");
+		if (!firmware_has_feature(FW_FEATURE_CMO))
+			sdev_printk(KERN_ERR, cmnd->device,
+			            "couldn't convert cmd to srp_cmd\n");
 		free_event_struct(&hostdata->pool, evt_struct);
 		return SCSI_MLQUEUE_HOST_BUSY;
 	}

@@ -855,7 +860,10 @@ static void send_mad_adapter_info(struct
 					    DMA_BIDIRECTIONAL);

=20
 	if (dma_mapping_error(req->buffer)) {
-		dev_err(hostdata->dev, "Unable to map request_buffer for adapter_info!\n=
");
+		if (!firmware_has_feature(FW_FEATURE_CMO))
+			dev_err(hostdata->dev,
+			        "Unable to map request_buffer for "
+			        "adapter_info!\n");
 		free_event_struct(&hostdata->pool, evt_struct);
 		return;
 	}

@@ -1400,7 +1408,9 @@ static int ibmvscsi_do_host_config(struc
 						    DMA_BIDIRECTIONAL);

=20
 	if (dma_mapping_error(host_config->buffer)) {
-		dev_err(hostdata->dev, "dma_mapping error getting host config\n");
+		if (!firmware_has_feature(FW_FEATURE_CMO))
+			dev_err(hostdata->dev,
+			        "dma_mapping error getting host config\n");
 		free_event_struct(&hostdata->pool, evt_struct);
 		return -1;
 	}

@@ -1604,7 +1614,7 @@ static struct scsi_host_template driver_
 	.eh_host_reset_handler =3D ibmvscsi_eh_host_reset_handler,
 	.slave_configure =3D ibmvscsi_slave_configure,
 	.change_queue_depth =3D ibmvscsi_change_queue_depth,
-	.cmd_per_lun =3D 16,
+	.cmd_per_lun =3D IBMVSCSI_CMDS_PER_LUN_DEFAULT,
 	.can_queue =3D IBMVSCSI_MAX_REQUESTS_DEFAULT,
 	.this_id =3D -1,
 	.sg_tablesize =3D SG_ALL,

@@ -1613,6 +1623,26 @@ static struct scsi_host_template driver_
 };

=20
 /**
+ * ibmvscsi_get_desired_dma - Calculate IO memory desired by the driver
+ *
+ * @vdev: struct vio_dev for the device whose desired IO mem is to be retu=
rned
+ *
+ * Return value:
+ *	Number of bytes of IO data the driver will need to perform well.
+ */
+static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
+{
+	/* iu_storage data allocated in initialize_event_pool */
+	unsigned long desired_io =3D max_requests * sizeof(union viosrp_iu);
+
+	/* add io space for sg data */
+	desired_io +=3D (IBMVSCSI_MAX_SECTORS_DEFAULT *
+	                     IBMVSCSI_CMDS_PER_LUN_DEFAULT);
+
+	return desired_io;
+}
+
+/**
  * Called by bus code for each adapter
  */
 static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id=
 *id)

@@ -1641,7 +1671,7 @@ static int ibmvscsi_probe(struct vio_dev
 	hostdata->host =3D host;
 	hostdata->dev =3D dev;
 	atomic_set(&hostdata->request_limit, -1);
-	hostdata->host->max_sectors =3D 32 * 8; /* default max I/O 32 pages */
+	hostdata->host->max_sectors =3D IBMVSCSI_MAX_SECTORS_DEFAULT;

=20
 	rc =3D ibmvscsi_ops->init_crq_queue(&hostdata->queue, hostdata, max_reque=
sts);
 	if (rc !=3D 0 && rc !=3D H_RESOURCE) {

@@ -1735,6 +1765,7 @@ static struct vio_driver ibmvscsi_driver
 	.id_table =3D ibmvscsi_device_table,
 	.probe =3D ibmvscsi_probe,
 	.remove =3D ibmvscsi_remove,
+	.get_desired_dma =3D ibmvscsi_get_desired_dma,
 	.driver =3D {
 		.name =3D "ibmvscsi",
 		.owner =3D THIS_MODULE,

Index: b/drivers/scsi/ibmvscsi/ibmvscsi.h
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

--- a/drivers/scsi/ibmvscsi/ibmvscsi.h
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.h

@@ -45,6 +45,8 @@ struct Scsi_Host;
 #define MAX_INDIRECT_BUFS 10

=20
 #define IBMVSCSI_MAX_REQUESTS_DEFAULT 100
+#define IBMVSCSI_CMDS_PER_LUN_DEFAULT 16
+#define IBMVSCSI_MAX_SECTORS_DEFAULT 256 /* 32 * 8 =3D default max I/O 32 =
pages */
 #define IBMVSCSI_MAX_CMDS_PER_LUN 64
=20
 /* ------------------------------------------------------------