ibmvscsi: driver enablement for CMO

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 <rcj@linux.vnet.ibm.com>
Acked by: Brian King <brking@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 40 insertions, 7 deletions

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 5d23368a1bce..20000ec79b04 100644
--- 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 *cmd,
                                            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 scsi_cmnd *cmnd,
         srp_cmd->lun = ((u64) lun) << 48;
 
         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 ibmvscsi_host_data *hostdata)
                                             DMA_BIDIRECTIONAL);
 
         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(struct ibmvscsi_host_data *hostdata,
                                                     DMA_BIDIRECTIONAL);
 
         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_template = {
         .eh_host_reset_handler = ibmvscsi_eh_host_reset_handler,
         .slave_configure = ibmvscsi_slave_configure,
         .change_queue_depth = ibmvscsi_change_queue_depth,
-        .cmd_per_lun = 16,
+        .cmd_per_lun = IBMVSCSI_CMDS_PER_LUN_DEFAULT,
         .can_queue = IBMVSCSI_MAX_REQUESTS_DEFAULT,
         .this_id = -1,
         .sg_tablesize = SG_ALL,
@@ -1613,6 +1623,26 @@ static struct scsi_host_template driver_template = {
 };
 
 /**
+ * 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 returned
+ *
+ * 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 = max_requests * sizeof(union viosrp_iu);
+
+        /* add io space for sg data */
+        desired_io += (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 *vdev, const struct vio_device_id *id)
         hostdata->host = host;
         hostdata->dev = dev;
         atomic_set(&hostdata->request_limit, -1);
-        hostdata->host->max_sectors = 32 * 8; /* default max I/O 32 pages */
+        hostdata->host->max_sectors = IBMVSCSI_MAX_SECTORS_DEFAULT;
 
         rc = ibmvscsi_ops->init_crq_queue(&hostdata->queue, hostdata, max_requests);
         if (rc != 0 && rc != H_RESOURCE) {
@@ -1735,6 +1765,7 @@ static struct vio_driver ibmvscsi_driver = {
         .id_table = ibmvscsi_device_table,
         .probe = ibmvscsi_probe,
         .remove = ibmvscsi_remove,
+        .get_desired_dma = ibmvscsi_get_desired_dma,
         .driver = {
                 .name = "ibmvscsi",
                 .owner = THIS_MODULE,
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.h b/drivers/scsi/ibmvscsi/ibmvscsi.h
index 46e850e302c7..2d4339d5e16e 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.h
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.h
@@ -45,6 +45,8 @@ struct Scsi_Host;
 #define MAX_INDIRECT_BUFS 10
 
 #define IBMVSCSI_MAX_REQUESTS_DEFAULT 100
+#define IBMVSCSI_CMDS_PER_LUN_DEFAULT 16
+#define IBMVSCSI_MAX_SECTORS_DEFAULT 256 /* 32 * 8 = default max I/O 32 pages */
 #define IBMVSCSI_MAX_CMDS_PER_LUN 64
 
 /* ------------------------------------------------------------