From b4200acdaf13f15f3c49178b27890a0fc3baada6 Mon Sep 17 00:00:00 2001
From: Vladislav Bolkhovitin <vst@vlnb.net>
Date: Tue, 5 Apr 2011 19:56:01 +0000
Subject: [PATCH] Possibility to specify human readable comments to targets
 (for instance, to specify which target maps to which port) added

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@3357 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 scst/include/scst.h   |  3 ++
 scst/src/scst_lib.c   |  1 +
 scst/src/scst_sysfs.c | 82 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)

diff --git a/scst/include/scst.h b/scst/include/scst.h
index 18d55e638..b3daed55f 100644
--- a/scst/include/scst.h
+++ b/scst/include/scst.h
@@ -1466,6 +1466,9 @@ struct scst_tgt {
 	/* Name of the target */
 	char *tgt_name;
 
+	/* User comment to it to let easier distinguish targets */
+	char *tgt_comment;
+
 	uint16_t rel_tgt_id;
 
 #ifdef CONFIG_SCST_PROC
diff --git a/scst/src/scst_lib.c b/scst/src/scst_lib.c
index 90259e3e5..748f3a6c8 100644
--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -2553,6 +2553,7 @@ void scst_free_tgt(struct scst_tgt *tgt)
 	TRACE_ENTRY();
 
 	kfree(tgt->tgt_name);
+	kfree(tgt->tgt_comment);
 #ifdef CONFIG_SCST_PROC
 	kfree(tgt->default_group_name);
 #endif
diff --git a/scst/src/scst_sysfs.c b/scst/src/scst_sysfs.c
index 82425e87e..2c6688b4d 100644
--- a/scst/src/scst_sysfs.c
+++ b/scst/src/scst_sysfs.c
@@ -2198,6 +2198,80 @@ 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_comment_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);
+
+	if (tgt->tgt_comment != NULL)
+		res = sprintf(buf, "%s\n%s", tgt->tgt_comment,
+			SCST_SYSFS_KEY_MARK "\n");
+	else
+		res = 0;
+
+	TRACE_EXIT_RES(res);
+	return res;
+}
+
+static ssize_t scst_tgt_comment_store(struct kobject *kobj,
+	struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	int res;
+	struct scst_tgt *tgt;
+	char *p;
+	int len;
+
+	TRACE_ENTRY();
+
+	if ((buf == NULL) || (count == 0)) {
+		res = 0;
+		goto out;
+	}
+
+	tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
+
+	len = strnlen(buf, count);
+	if (buf[count-1] == '\n')
+		len--;
+
+	if (len == 0) {
+		kfree(tgt->tgt_comment);
+		tgt->tgt_comment = NULL;
+		goto out_done;
+	}
+
+	p = kmalloc(len+1, GFP_KERNEL);
+	if (p == NULL) {
+		PRINT_ERROR("Unable to alloc tgt_comment string (len %d)",
+			len+1);
+		res = -ENOMEM;
+		goto out;
+	}
+
+	memcpy(p, buf, len);
+	p[len] = '\0';
+
+	kfree(tgt->tgt_comment);
+
+	tgt->tgt_comment = p;
+
+out_done:
+	res = count;
+
+out:
+	TRACE_EXIT_RES(res);
+	return res;
+}
+
+static struct kobj_attribute scst_tgt_comment =
+	__ATTR(comment, S_IRUGO | S_IWUSR, scst_tgt_comment_show,
+	       scst_tgt_comment_store);
+
 /*
  * Supposed to be called under scst_mutex. In case of error will drop,
  * then reacquire it.
@@ -2269,6 +2343,14 @@ int scst_tgt_sysfs_create(struct scst_tgt *tgt)
 		goto out_err;
 	}
 
+	res = sysfs_create_file(&tgt->tgt_kobj,
+			&scst_tgt_comment.attr);
+	if (res != 0) {
+		PRINT_ERROR("Can't add attribute %s for tgt %s",
+			scst_tgt_comment.attr.name, tgt->tgt_name);
+		goto out_err;
+	}
+
 	res = sysfs_create_file(&tgt->tgt_kobj,
 			&scst_tgt_addr_method.attr);
 	if (res != 0) {