[SCSI] iscsi: fixup set/get param functions

Reduce duplication in the software iscsi_transport modules by
adding a libiscsi function to handle the common grunt work.

This also has the drivers return specifc -EXXX values for different
errors so userspace can finally handle them in a sane way.

Also just pass the sysfs buffers to the drivers so HW iscsi can
get/set its string values, like targetname, and initiatorname.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/libiscsi.c

@@ -1697,6 +1697,185 @@ int iscsi_conn_bind(struct iscsi_cls_session *cls_session,
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_bind);
 
+
+int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
+		    enum iscsi_param param, char *buf, int buflen)
+{
+	struct iscsi_conn *conn = cls_conn->dd_data;
+	struct iscsi_session *session = conn->session;
+	uint32_t value;
+
+	switch(param) {
+	case ISCSI_PARAM_MAX_RECV_DLENGTH:
+		sscanf(buf, "%d", &conn->max_recv_dlength);
+		break;
+	case ISCSI_PARAM_MAX_XMIT_DLENGTH:
+		sscanf(buf, "%d", &conn->max_xmit_dlength);
+		break;
+	case ISCSI_PARAM_HDRDGST_EN:
+		sscanf(buf, "%d", &conn->hdrdgst_en);
+		break;
+	case ISCSI_PARAM_DATADGST_EN:
+		sscanf(buf, "%d", &conn->datadgst_en);
+		break;
+	case ISCSI_PARAM_INITIAL_R2T_EN:
+		sscanf(buf, "%d", &session->initial_r2t_en);
+		break;
+	case ISCSI_PARAM_MAX_R2T:
+		sscanf(buf, "%d", &session->max_r2t);
+		break;
+	case ISCSI_PARAM_IMM_DATA_EN:
+		sscanf(buf, "%d", &session->imm_data_en);
+		break;
+	case ISCSI_PARAM_FIRST_BURST:
+		sscanf(buf, "%d", &session->first_burst);
+		break;
+	case ISCSI_PARAM_MAX_BURST:
+		sscanf(buf, "%d", &session->max_burst);
+		break;
+	case ISCSI_PARAM_PDU_INORDER_EN:
+		sscanf(buf, "%d", &session->pdu_inorder_en);
+		break;
+	case ISCSI_PARAM_DATASEQ_INORDER_EN:
+		sscanf(buf, "%d", &session->dataseq_inorder_en);
+		break;
+	case ISCSI_PARAM_ERL:
+		sscanf(buf, "%d", &session->erl);
+		break;
+	case ISCSI_PARAM_IFMARKER_EN:
+		sscanf(buf, "%d", &value);
+		BUG_ON(value);
+		break;
+	case ISCSI_PARAM_OFMARKER_EN:
+		sscanf(buf, "%d", &value);
+		BUG_ON(value);
+		break;
+	case ISCSI_PARAM_EXP_STATSN:
+		sscanf(buf, "%u", &conn->exp_statsn);
+		break;
+	case ISCSI_PARAM_TARGET_NAME:
+		/* this should not change between logins */
+		if (session->targetname)
+			break;
+
+		session->targetname = kstrdup(buf, GFP_KERNEL);
+		if (!session->targetname)
+			return -ENOMEM;
+		break;
+	case ISCSI_PARAM_TPGT:
+		sscanf(buf, "%d", &session->tpgt);
+		break;
+	case ISCSI_PARAM_PERSISTENT_PORT:
+		sscanf(buf, "%d", &conn->persistent_port);
+		break;
+	case ISCSI_PARAM_PERSISTENT_ADDRESS:
+		/*
+		 * this is the address returned in discovery so it should
+		 * not change between logins.
+		 */
+		if (conn->persistent_address)
+			break;
+
+		conn->persistent_address = kstrdup(buf, GFP_KERNEL);
+		if (!conn->persistent_address)
+			return -ENOMEM;
+		break;
+	default:
+		return -ENOSYS;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iscsi_set_param);
+
+int iscsi_session_get_param(struct iscsi_cls_session *cls_session,
+			    enum iscsi_param param, char *buf)
+{
+	struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
+	struct iscsi_session *session = iscsi_hostdata(shost->hostdata);
+	int len;
+
+	switch(param) {
+	case ISCSI_PARAM_INITIAL_R2T_EN:
+		len = sprintf(buf, "%d\n", session->initial_r2t_en);
+		break;
+	case ISCSI_PARAM_MAX_R2T:
+		len = sprintf(buf, "%hu\n", session->max_r2t);
+		break;
+	case ISCSI_PARAM_IMM_DATA_EN:
+		len = sprintf(buf, "%d\n", session->imm_data_en);
+		break;
+	case ISCSI_PARAM_FIRST_BURST:
+		len = sprintf(buf, "%u\n", session->first_burst);
+		break;
+	case ISCSI_PARAM_MAX_BURST:
+		len = sprintf(buf, "%u\n", session->max_burst);
+		break;
+	case ISCSI_PARAM_PDU_INORDER_EN:
+		len = sprintf(buf, "%d\n", session->pdu_inorder_en);
+		break;
+	case ISCSI_PARAM_DATASEQ_INORDER_EN:
+		len = sprintf(buf, "%d\n", session->dataseq_inorder_en);
+		break;
+	case ISCSI_PARAM_ERL:
+		len = sprintf(buf, "%d\n", session->erl);
+		break;
+	case ISCSI_PARAM_TARGET_NAME:
+		len = sprintf(buf, "%s\n", session->targetname);
+		break;
+	case ISCSI_PARAM_TPGT:
+		len = sprintf(buf, "%d\n", session->tpgt);
+		break;
+	default:
+		return -ENOSYS;
+	}
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(iscsi_session_get_param);
+
+int iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
+			 enum iscsi_param param, char *buf)
+{
+	struct iscsi_conn *conn = cls_conn->dd_data;
+	int len;
+
+	switch(param) {
+	case ISCSI_PARAM_MAX_RECV_DLENGTH:
+		len = sprintf(buf, "%u\n", conn->max_recv_dlength);
+		break;
+	case ISCSI_PARAM_MAX_XMIT_DLENGTH:
+		len = sprintf(buf, "%u\n", conn->max_xmit_dlength);
+		break;
+	case ISCSI_PARAM_HDRDGST_EN:
+		len = sprintf(buf, "%d\n", conn->hdrdgst_en);
+		break;
+	case ISCSI_PARAM_DATADGST_EN:
+		len = sprintf(buf, "%d\n", conn->datadgst_en);
+		break;
+	case ISCSI_PARAM_IFMARKER_EN:
+		len = sprintf(buf, "%d\n", conn->ifmarker_en);
+		break;
+	case ISCSI_PARAM_OFMARKER_EN:
+		len = sprintf(buf, "%d\n", conn->ofmarker_en);
+		break;
+	case ISCSI_PARAM_EXP_STATSN:
+		len = sprintf(buf, "%u\n", conn->exp_statsn);
+		break;
+	case ISCSI_PARAM_PERSISTENT_PORT:
+		len = sprintf(buf, "%d\n", conn->persistent_port);
+		break;
+	case ISCSI_PARAM_PERSISTENT_ADDRESS:
+		len = sprintf(buf, "%s\n", conn->persistent_address);
+		break;
+	default:
+		return -ENOSYS;
+	}
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_get_param);
+
 MODULE_AUTHOR("Mike Christie");
 MODULE_DESCRIPTION("iSCSI library functions");
 MODULE_LICENSE("GPL");

include/scsi/libiscsi.h

@@ -157,6 +157,11 @@ struct iscsi_conn {
 	int			max_xmit_dlength; /* target_max_recv_dsl */
 	int			hdrdgst_en;
 	int			datadgst_en;
+	int			ifmarker_en;
+	int			ofmarker_en;
+	/* values userspace uses to id a conn */
+	int			persistent_port;
+	char			*persistent_address;
 
 	/* MIB-statistics */
 	uint64_t		txdata_octets;
@@ -196,8 +201,8 @@ struct iscsi_session {
 	int			pdu_inorder_en;
 	int			dataseq_inorder_en;
 	int			erl;
-	int			ifmarker_en;
-	int			ofmarker_en;
+	int			tpgt;
+	char			*targetname;
 
 	/* control data */
 	struct iscsi_transport	*tt;
@@ -240,6 +245,10 @@ iscsi_session_setup(struct iscsi_transport *, struct scsi_transport_template *,
 extern void iscsi_session_teardown(struct iscsi_cls_session *);
 extern struct iscsi_session *class_to_transport_session(struct iscsi_cls_session *);
 extern void iscsi_session_recovery_timedout(struct iscsi_cls_session *);
+extern int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
+			   enum iscsi_param param, char *buf, int buflen);
+extern int iscsi_session_get_param(struct iscsi_cls_session *cls_session,
+				   enum iscsi_param param, char *buf);
 
 #define session_to_cls(_sess) \
 	hostdata_session(_sess->host->hostdata)
@@ -255,6 +264,8 @@ extern void iscsi_conn_stop(struct iscsi_cls_conn *, int);
 extern int iscsi_conn_bind(struct iscsi_cls_session *, struct iscsi_cls_conn *,
 			   int);
 extern void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err);
+extern int iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
+				enum iscsi_param param, char *buf);
 
 /*
  * pdu and task processing

include/scsi/scsi_transport_iscsi.h

@@ -34,6 +34,7 @@ struct iscsi_cls_conn;
 struct iscsi_conn;
 struct iscsi_cmd_task;
 struct iscsi_mgmt_task;
+struct sockaddr;
 
 /**
  * struct iscsi_transport - iSCSI Transport template
@@ -46,7 +47,12 @@ struct iscsi_mgmt_task;
  * @bind_conn:		associate this connection with existing iSCSI session
  *			and specified transport descriptor
  * @destroy_conn:	destroy inactive iSCSI connection
- * @set_param:		set iSCSI Data-Path operational parameter
+ * @set_param:		set iSCSI parameter. Return 0 on success, -ENODATA
+ *			when param is not supported, and a -Exx value on other
+ *			error.
+ * @get_param		get iSCSI parameter. Must return number of bytes
+ *			copied to buffer on success, -ENODATA when param
+ *			is not supported, and a -Exx value on other error
  * @start_conn:		set connection to be operational
  * @stop_conn:		suspend/recover/terminate connection
  * @send_pdu:		send iSCSI PDU, Login, Logout, NOP-Out, Reject, Text.
@@ -97,15 +103,11 @@ struct iscsi_transport {
 	void (*stop_conn) (struct iscsi_cls_conn *conn, int flag);
 	void (*destroy_conn) (struct iscsi_cls_conn *conn);
 	int (*set_param) (struct iscsi_cls_conn *conn, enum iscsi_param param,
-			  uint32_t value);
+			  char *buf, int buflen);
 	int (*get_conn_param) (struct iscsi_cls_conn *conn,
-			       enum iscsi_param param, uint32_t *value);
+			       enum iscsi_param param, char *buf);
 	int (*get_session_param) (struct iscsi_cls_session *session,
-				  enum iscsi_param param, uint32_t *value);
-	int (*get_conn_str_param) (struct iscsi_cls_conn *conn,
-				   enum iscsi_param param, char *buf);
-	int (*get_session_str_param) (struct iscsi_cls_session *session,
-				      enum iscsi_param param, char *buf);
+				  enum iscsi_param param, char *buf);
 	int (*send_pdu) (struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
 			 char *data, uint32_t data_size);
 	void (*get_stats) (struct iscsi_cls_conn *conn,
@@ -157,13 +159,6 @@ struct iscsi_cls_conn {
 	struct iscsi_transport *transport;
 	uint32_t cid;			/* connection id */
 
-	/* portal/group values we got during discovery */
-	char *persistent_address;
-	int persistent_port;
-	/* portal/group values we are currently using */
-	char *address;
-	int port;
-
 	int active;			/* must be accessed with the connlock */
 	struct device dev;		/* sysfs transport/container device */
 	struct mempool_zone *z_error;
@@ -187,10 +182,6 @@ struct iscsi_cls_session {
 	struct list_head host_list;
 	struct iscsi_transport *transport;
 
-	/* iSCSI values used as unique id by userspace. */
-	char *targetname;
-	int tpgt;
-
 	/* recovery fields */
 	int recovery_tmo;
 	struct work_struct recovery_work;