[SCSI] zfcp: Introduce experimental support for DIF/DIX

Introduce support for DIF/DIX in zfcp: Report the capabilities for the
Scsi_host, map the protection data when issuing I/O requests and
handle the new error codes. Also add the fsf data_direction field to
the hba trace, it is useful information for debugging in that area.
This is an EXPERIMENTAL feature for now.

Signed-off-by: Felix Beck <felix.beck@de.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index eb471a1723cd..cb000c9833bb 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -12,6 +12,7 @@
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <scsi/fc/fc_fcp.h>
+#include <scsi/scsi_eh.h>
 #include <asm/atomic.h>
 #include "zfcp_ext.h"
 #include "zfcp_dbf.h"
@@ -22,6 +23,13 @@ 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");
 
+static bool enable_dif;
+
+#ifdef CONFIG_ZFCP_DIF
+module_param_named(dif, enable_dif, bool, 0600);
+MODULE_PARM_DESC(dif, "Enable DIF/DIX data integrity support");
+#endif
+
 static int zfcp_scsi_change_queue_depth(struct scsi_device *sdev, int depth,
                                         int reason)
 {
@@ -652,6 +660,51 @@ void zfcp_scsi_scan_work(struct work_struct *work)
         put_device(&unit->dev);
 }
 
+/**
+ * zfcp_scsi_set_prot - Configure DIF/DIX support in scsi_host
+ * @adapter: The adapter where to configure DIF/DIX for the SCSI host
+ */
+void zfcp_scsi_set_prot(struct zfcp_adapter *adapter)
+{
+        unsigned int mask = 0;
+        unsigned int data_div;
+        struct Scsi_Host *shost = adapter->scsi_host;
+
+        data_div = atomic_read(&adapter->status) &
+                   ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED;
+
+        if (enable_dif &&
+            adapter->adapter_features & FSF_FEATURE_DIF_PROT_TYPE1)
+                mask |= SHOST_DIF_TYPE1_PROTECTION;
+
+        if (enable_dif && data_div &&
+            adapter->adapter_features & FSF_FEATURE_DIX_PROT_TCPIP) {
+                mask |= SHOST_DIX_TYPE1_PROTECTION;
+                scsi_host_set_guard(shost, SHOST_DIX_GUARD_IP);
+                shost->sg_tablesize = ZFCP_QDIO_MAX_SBALES_PER_REQ / 2;
+                shost->max_sectors = ZFCP_QDIO_MAX_SBALES_PER_REQ * 8 / 2;
+        }
+
+        scsi_host_set_prot(shost, mask);
+}
+
+/**
+ * zfcp_scsi_dif_sense_error - Report DIF/DIX error as driver sense error
+ * @scmd: The SCSI command to report the error for
+ * @ascq: The ASCQ to put in the sense buffer
+ *
+ * See the error handling in sd_done for the sense codes used here.
+ * Set DID_SOFT_ERROR to retry the request, if possible.
+ */
+void zfcp_scsi_dif_sense_error(struct scsi_cmnd *scmd, int ascq)
+{
+        scsi_build_sense_buffer(1, scmd->sense_buffer,
+                                ILLEGAL_REQUEST, 0x10, ascq);
+        set_driver_byte(scmd, DRIVER_SENSE);
+        scmd->result |= SAM_STAT_CHECK_CONDITION;
+        set_host_byte(scmd, DID_SOFT_ERROR);
+}
+
 struct fc_function_template zfcp_transport_functions = {
         .show_starget_port_id = 1,
         .show_starget_port_name = 1,