zfcp: support SCSI_ADAPTER_RESET via scsi_host sysfs attribute host_reset

Make use of feature introduced with v3.2 commit 294436914454 ("[SCSI] scsi: Added support for adapter and firmware reset"). The common code interface was introduced for commit 95d31262b3c1 ("[SCSI] qla4xxx: Added support for adapter and firmware reset").

$ echo adapter > /sys/class/scsi_host/host<N>/host_reset

Example trace record formatted with zfcpdbf from s390-tools:

Timestamp : ...
Area : REC
Subarea : 00
Level : 1
Exception : -
CPU ID : ..
Caller : 0x...
Record ID : 1 ZFCP_DBF_REC_TRIG
Tag : scshr_y SCSI sysfs host_reset yes
LUN : 0xffffffffffffffff none (invalid)
WWPN : 0x0000000000000000 none (invalid)
D_ID : 0x00000000 none (invalid)
Adapter status : 0x4500050b
Port status : 0x00000000 none (invalid)
LUN status : 0x00000000 none (invalid)
Ready count : 0x00000001
Running count : 0x00000000
ERP want : 0x04 ZFCP_ERP_ACTION_REOPEN_ADAPTER
ERP need : 0x04 ZFCP_ERP_ACTION_REOPEN_ADAPTER

This is the common code equivalent to the zfcp-specific &dev_attr_adapter_failed.attr in zfcp_sysfs_adapter_attrs.attrs[]:

$ echo 0 > /sys/bus/ccw/drivers/zfcp/<devbusid>/failed

The unsupported case returns EOPNOTSUPP:

$ echo firmware > /sys/class/scsi_host/host<N>/host_reset
-bash: echo: write error: Operation not supported

Example trace record formatted with zfcpdbf from s390-tools:

Timestamp : ...
Area : SCSI
Subarea : 00
Level : 1
Exception : -
CPU ID : ..
Caller : 0x...
Record ID : 1
Tag : scshr_n SCSI sysfs host_reset no
Request ID : 0x0000000000000000 none (invalid)
SCSI ID : 0xffffffff none (invalid)
SCSI LUN : 0xffffffff none (invalid)
SCSI LUN high : 0xffffffff none (invalid)
SCSI result : 0xffffffa1 -EOPNOTSUPP==-95
SCSI retries : 0xff none (invalid)
SCSI allowed : 0xff none (invalid)
SCSI scribble : 0xffffffffffffffff none (invalid)
SCSI opcode : ffffffff ffffffff ffffffff ffffffff none (invalid)
FCP rsp inf cod: 0xff none (invalid)
FCP rsp IU : 00000000 00000000 00000000 00000000 none (invalid)

                 00000000 00000000

For any other invalid value, common code returns EINVAL without invoking our callback:

$ echo foo > /sys/class/scsi_host/host<N>/host_reset
-bash: echo: write error: Invalid argument

---
 drivers/s390/scsi/zfcp_erp.c   | 11 +++++++++++
 drivers/s390/scsi/zfcp_ext.h   |  1 +
 drivers/s390/scsi/zfcp_scsi.c  | 26 ++++++++++++++++++++++++++
 drivers/s390/scsi/zfcp_sysfs.c |  5 +----
 4 files changed, 39 insertions(+), 4 deletions(-)

index 2968d2f57788..e7e6b63905e2 100644
@@ -1691,3 +1691,14 @@ void zfcp_erp_clear_lun_status(struct scsi_device *sdev, u32 mask)
 		atomic_set(&zfcp_sdev->erp_counter, 0);
 }
 
+/**
+ * zfcp_erp_adapter_reset_sync() - Really reopen adapter and wait.
+ * @adapter: Pointer to zfcp_adapter to reopen.
+ * @id: Trace tag string of length %ZFCP_DBF_TAG_LEN.
+ */
+void zfcp_erp_adapter_reset_sync(struct zfcp_adapter *adapter, char *id)
+{
+	zfcp_erp_set_adapter_status(adapter, ZFCP_STATUS_COMMON_RUNNING);
+	zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED, id);
+	zfcp_erp_wait(adapter);
+}

index ad7c28ffd49f..f3b55cce748a 100644
@@ -76,6 +76,7 @@ extern void zfcp_erp_thread_kill(struct zfcp_adapter *);
 extern void zfcp_erp_wait(struct zfcp_adapter *);
 extern void zfcp_erp_notify(struct zfcp_erp_action *, unsigned long);
 extern void zfcp_erp_timeout_handler(struct timer_list *t);
+extern void zfcp_erp_adapter_reset_sync(struct zfcp_adapter *adapter, char *id);
 
 /* zfcp_fc.c */
 extern struct kmem_cache *zfcp_fc_req_cache;

index f69ef78ea930..9a01f583e562 100644
@@ -372,6 +372,31 @@ static int zfcp_scsi_eh_host_reset_handler(struct scsi_cmnd *scpnt)
 	return ret;
 }
 
+/**
+ * zfcp_scsi_sysfs_host_reset() - Support scsi_host sysfs attribute host_reset.
+ * @shost: Pointer to Scsi_Host to perform action on.
+ * @reset_type: We support %SCSI_ADAPTER_RESET but not %SCSI_FIRMWARE_RESET.
+ *
+ * Return: 0 on %SCSI_ADAPTER_RESET, -%EOPNOTSUPP otherwise.
+ *
+ * This is similar to zfcp_sysfs_adapter_failed_store().
+ */
+static int zfcp_scsi_sysfs_host_reset(struct Scsi_Host *shost, int reset_type)
+{
+	struct zfcp_adapter *adapter =
+		(struct zfcp_adapter *)shost->hostdata[0];
+	int ret = 0;
+
+	if (reset_type != SCSI_ADAPTER_RESET) {
+		ret = -EOPNOTSUPP;
+		zfcp_dbf_scsi_eh("scshr_n", adapter, ~0, ret);
+		return ret;
+	}
+
+	zfcp_erp_adapter_reset_sync(adapter, "scshr_y");
+	return ret;
+}
+
 struct scsi_transport_template *zfcp_scsi_transport_template;
 
 static struct scsi_host_template zfcp_scsi_host_template = {

@@ -387,6 +412,7 @@ static struct scsi_host_template zfcp_scsi_host_template = {
 	.slave_configure	 = zfcp_scsi_slave_configure,
 	.slave_destroy		 = zfcp_scsi_slave_destroy,
 	.change_queue_depth	 = scsi_change_queue_depth,
+	.host_reset		 = zfcp_scsi_sysfs_host_reset,
 	.proc_name		 = "zfcp",
 	.can_queue		 = 4096,
 	.this_id		 = -1,

index 3ac823f2540f..b277be6f7611 100644
@@ -200,10 +200,7 @@ static ssize_t zfcp_sysfs_adapter_failed_store(struct device *dev,
 		goto out;
 	}
 
-	zfcp_erp_set_adapter_status(adapter, ZFCP_STATUS_COMMON_RUNNING);
-	zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED,
-				"syafai2");
-	zfcp_erp_wait(adapter);
+	zfcp_erp_adapter_reset_sync(adapter, "syafai2");
 out:
 	zfcp_ccw_adapter_put(adapter);
 	return retval ? retval : (ssize_t) count;

2.16.3