Patch from Alexey Obitotskiy <alexeyo1@open-e.com> with cleanups and fixes implementing setting and managing relative target IDs.

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@1523 d57e44dd-8a1f-0410-8b47-8ef2f437770f

scst/include/scst.h

@@ -1180,8 +1180,10 @@ struct scst_tgt {
 	/* Name of the target */
 	char *tgt_name;
 
+	uint16_t rel_tgt_id;
+
 #ifdef CONFIG_SCST_PROC
-	/* Name on the default security group ("Default_target_name") */
+	/* Name of the default security group ("Default_target_name") */
 	char *default_group_name;
 #endif
 

scst/include/scst_const.h

@@ -355,4 +355,7 @@ enum scst_cdb_flags {
 
 #define SCST_SYSFS_KEY_MARK	"[key]"
 
+#define SCST_MIN_REL_TGT_ID			1
+#define SCST_MAX_REL_TGT_ID			65535
+
 #endif /* __SCST_CONST_H */

scst/src/scst_lib.c

@@ -1881,32 +1881,96 @@ restart:
 	return;
 }
 
-struct scst_tgt *scst_alloc_tgt(struct scst_tgt_template *tgtt)
+bool scst_is_relative_target_port_id_unique(uint16_t id, struct scst_tgt *t)
 {
-	struct scst_tgt *tgt;
+	bool res = true;
+	struct scst_tgt_template *tgtt;
 
 	TRACE_ENTRY();
 
-	tgt = kzalloc(sizeof(*tgt), GFP_KERNEL);
-	if (tgt == NULL) {
+	mutex_lock(&scst_mutex);
+	list_for_each_entry(tgtt, &scst_template_list,
+				scst_template_list_entry) {
+		struct scst_tgt *tgt;
+		list_for_each_entry(tgt, &tgtt->tgt_list, tgt_list_entry) {
+			if (tgt == t)
+				continue;
+			if (id == tgt->rel_tgt_id) {
+				res = false;
+				break;
+			}
+		}
+	}
+	mutex_unlock(&scst_mutex);
+
+	TRACE_EXIT_RES(res);
+	return res;
+}
+
+int gen_relative_target_port_id(uint16_t *id)
+{
+	int res = -EOVERFLOW;
+	static unsigned long rti = SCST_MIN_REL_TGT_ID, rti_prev;
+
+	TRACE_ENTRY();
+
+	rti_prev = rti;
+	do {
+		if (scst_is_relative_target_port_id_unique(rti, NULL)) {
+			*id = (uint16_t)rti++;
+			res = 0;
+			goto out;
+		}
+		rti++;
+		if (rti > SCST_MAX_REL_TGT_ID)
+			rti = SCST_MIN_REL_TGT_ID;
+	} while (rti != rti_prev);
+
+	PRINT_ERROR("%s", "Unable to create unique relative target port id");
+
+out:
+	TRACE_EXIT_RES(res);
+	return res;
+}
+
+int scst_alloc_tgt(struct scst_tgt_template *tgtt, struct scst_tgt **tgt)
+{
+	struct scst_tgt *t;
+	int res = 0;
+
+	TRACE_ENTRY();
+
+	t = kzalloc(sizeof(*t), GFP_KERNEL);
+	if (t == NULL) {
 		TRACE(TRACE_OUT_OF_MEM, "%s", "Allocation of tgt failed");
+		res = -ENOMEM;
 		goto out;
 	}
 
-	INIT_LIST_HEAD(&tgt->sess_list);
-	init_waitqueue_head(&tgt->unreg_waitQ);
-	tgt->tgtt = tgtt;
-	tgt->sg_tablesize = tgtt->sg_tablesize;
-	spin_lock_init(&tgt->tgt_lock);
-	INIT_LIST_HEAD(&tgt->retry_cmd_list);
-	atomic_set(&tgt->finished_cmds, 0);
-	init_timer(&tgt->retry_timer);
-	tgt->retry_timer.data = (unsigned long)tgt;
-	tgt->retry_timer.function = scst_tgt_retry_timer_fn;
+	INIT_LIST_HEAD(&t->sess_list);
+	init_waitqueue_head(&t->unreg_waitQ);
+	t->tgtt = tgtt;
+	t->sg_tablesize = tgtt->sg_tablesize;
+	spin_lock_init(&t->tgt_lock);
+	INIT_LIST_HEAD(&t->retry_cmd_list);
+	atomic_set(&t->finished_cmds, 0);
+	init_timer(&t->retry_timer);
+	t->retry_timer.data = (unsigned long)t;
+	t->retry_timer.function = scst_tgt_retry_timer_fn;
+
+#ifdef CONFIG_SCST_PROC
+	res = gen_relative_target_port_id(&t->rel_tgt_id);
+	if (res != 0) {
+		scst_free_tgt(t);
+		goto out;
+	}
+#endif
+
+	*tgt = t;
 
 out:
-	TRACE_EXIT_HRES((unsigned long)tgt);
-	return tgt;
+	TRACE_EXIT_HRES(res);
+	return res;
 }
 
 void scst_free_tgt(struct scst_tgt *tgt)

scst/src/scst_main.c

@@ -361,11 +361,9 @@ struct scst_tgt *scst_register(struct scst_tgt_template *vtt,
 
 	TRACE_ENTRY();
 
-	tgt = scst_alloc_tgt(vtt);
-	if (tgt == NULL) {
-		rc = -ENOMEM;
+	rc = scst_alloc_tgt(vtt, &tgt);
+	if (rc != 0)
 		goto out_err;
-	}
 
 	rc = scst_suspend_activity(true);
 	if (rc != 0)
@@ -449,8 +447,13 @@ struct scst_tgt *scst_register(struct scst_tgt_template *vtt,
 	mutex_unlock(&scst_mutex);
 	scst_resume_activity();
 
+#ifdef CONFIG_SCST_PROC
+	PRINT_INFO("Target %s (rel ID %d) for template %s registered successfully",
+		tgt->tgt_name, tgt->rel_tgt_id, vtt->name);
+#else
 	PRINT_INFO("Target %s for template %s registered successfully",
 		tgt->tgt_name, vtt->name);
+#endif
 
 	TRACE_DBG("tgt %p", tgt);
 

scst/src/scst_priv.h

@@ -296,7 +296,7 @@ int scst_queue_retry_cmd(struct scst_cmd *cmd, int finished_cmds);
 static inline void scst_tgtt_cleanup(struct scst_tgt_template *tgtt) { }
 static inline void scst_devt_cleanup(struct scst_dev_type *devt) { }
 
-struct scst_tgt *scst_alloc_tgt(struct scst_tgt_template *tgtt);
+int scst_alloc_tgt(struct scst_tgt_template *tgtt, struct scst_tgt **tgt);
 void scst_free_tgt(struct scst_tgt *tgt);
 
 int scst_alloc_device(gfp_t gfp_mask, struct scst_device **out_dev);
@@ -735,6 +735,9 @@ static inline int scst_sn_before(__u32 seq1, __u32 seq2)
 	return (__s32)(seq1-seq2) < 0;
 }
 
+bool scst_is_relative_target_port_id_unique(uint16_t id, struct scst_tgt *t);
+int gen_relative_target_port_id(uint16_t *id);
+
 #ifdef CONFIG_SCST_MEASURE_LATENCY
 
 void scst_set_start_time(struct scst_cmd *cmd);

scst/src/scst_sysfs.c

@@ -112,6 +112,12 @@ static ssize_t scst_ini_group_mgmt_show(struct kobject *kobj,
 static ssize_t scst_ini_group_mgmt_store(struct kobject *kobj,
 				    struct kobj_attribute *attr,
 				    const char *buf, size_t count);
+static ssize_t scst_rel_tgt_id_show(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   char *buf);
+static ssize_t scst_rel_tgt_id_store(struct kobject *kobj,
+				    struct kobj_attribute *attr,
+				    const char *buf, size_t count);
 static ssize_t scst_acg_luns_mgmt_show(struct kobject *kobj,
 				   struct kobj_attribute *attr,
 				   char *buf);
@@ -526,6 +532,10 @@ static struct kobj_attribute scst_ini_group_mgmt =
 	__ATTR(mgmt, S_IRUGO | S_IWUSR, scst_ini_group_mgmt_show,
 	       scst_ini_group_mgmt_store);
 
+static struct kobj_attribute scst_rel_tgt_id =
+	__ATTR(rel_tgt_id, S_IRUGO | S_IWUSR, scst_rel_tgt_id_show,
+	       scst_rel_tgt_id_store);
+
 static ssize_t scst_tgt_enable_show(struct kobject *kobj,
 	struct kobj_attribute *attr, char *buf)
 {
@@ -558,6 +568,23 @@ static ssize_t scst_tgt_enable_store(struct kobject *kobj,
 
 	tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
 
+	if (buf[0] == '1') {
+		if (tgt->rel_tgt_id == 0) {
+			res = gen_relative_target_port_id(&tgt->rel_tgt_id);
+			if (res)
+				goto out;
+			PRINT_INFO("Using autogenerated rel ID %d for target "
+				"%s", tgt->rel_tgt_id, tgt->tgt_name);
+		} else
+			if (!scst_is_relative_target_port_id_unique(
+			    tgt->rel_tgt_id, tgt)) {
+				PRINT_ERROR("Relative port id %d is not unique",
+					tgt->rel_tgt_id);
+					res = -EBADSLT;
+				goto out;
+			}
+	}
+
 	res = tgt->tgtt->enable_target(tgt, buf, count);
 	if (res == 0)
 		res = count;
@@ -638,13 +665,21 @@ int scst_create_tgt_sysfs(struct scst_tgt *tgt)
 	}
 
 	retval = sysfs_create_file(tgt->tgt_ini_grp_kobj,
-		&scst_ini_group_mgmt.attr);
+			&scst_ini_group_mgmt.attr);
 	if (retval != 0) {
 		PRINT_ERROR("Can't add tgt attr %s for tgt %s",
 			scst_ini_group_mgmt.attr.name, tgt->tgt_name);
 		goto out;
 	}
 
+	retval = sysfs_create_file(&tgt->tgt_kobj,
+			&scst_rel_tgt_id.attr);
+	if (retval != 0) {
+		PRINT_ERROR("Can't add attribute %s for tgt %s",
+			scst_rel_tgt_id.attr.name, tgt->tgt_name);
+		goto out;
+	}
+
 	pattr = tgt->tgtt->tgt_attrs;
 	if (pattr != NULL) {
 		while (*pattr != NULL) {
@@ -1797,6 +1832,80 @@ out_free_acg:
 #undef SCST_LUN_ACTION_DEL
 }
 
+static ssize_t scst_rel_tgt_id_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	struct scst_tgt *tgt;
+	int res;
+
+	TRACE_ENTRY();
+
+	tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
+
+	res = sprintf(buf, "%d\n%s", tgt->rel_tgt_id,
+		(tgt->rel_tgt_id != 0) ? SCST_SYSFS_KEY_MARK "\n" : "");
+
+	TRACE_EXIT_RES(res);
+	return res;
+}
+
+static ssize_t scst_rel_tgt_id_store(struct kobject *kobj,
+	struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	int res = 0;
+	struct scst_tgt *tgt;
+	unsigned long rel_tgt_id;
+
+	TRACE_ENTRY();
+
+	if (buf == NULL)
+		goto out_err;
+
+	tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
+
+	res = strict_strtoul(buf, 0, &rel_tgt_id);
+	if (res != 0)
+		goto out_err;
+
+	TRACE_DBG("Try to set relative target port id %d",
+		(uint16_t)rel_tgt_id);
+
+	if (rel_tgt_id < SCST_MIN_REL_TGT_ID ||
+	    rel_tgt_id > SCST_MAX_REL_TGT_ID) {
+	    	if ((rel_tgt_id == 0) && !tgt->tgtt->is_target_enabled(tgt))
+	    		goto set;
+
+		PRINT_ERROR("Invalid relative port id %d",
+			(uint16_t)rel_tgt_id);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (tgt->tgtt->is_target_enabled(tgt) &&
+	    rel_tgt_id != tgt->rel_tgt_id) {
+		if (!scst_is_relative_target_port_id_unique(rel_tgt_id, tgt)) {
+			PRINT_ERROR("Relative port id %d is not unique",
+				(uint16_t)rel_tgt_id);
+			res = -EBADSLT;
+			goto out;
+		}
+	}
+
+set:
+	tgt->rel_tgt_id = (uint16_t)rel_tgt_id;
+
+	res = count;
+
+out:
+	TRACE_EXIT_RES(res);
+	return res;
+
+out_err:
+	PRINT_ERROR("%s: Requested action not understood: %s", __func__, buf);
+	res = -EINVAL;
+	goto out;
+}
+
 int scst_create_acn_sysfs(struct scst_acg *acg, struct scst_acn *acn)
 {
 	int retval = 0;