From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds the ConfigFS extended macro set in CONFIGFS_EATTR_*() that are used
by TCM/ConfigFS >= v3.x subsystem backstores and v4 generic fabric configfs infrastructure
and CPP macro set.
Compared to the original configfs macro set in include/linux/configfs.h, the extended macro
set allows for more flexability to handle multiple struct config_groups hanging off a single
parent data structure for more complex consumer logic and with less LOC!
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
include/target/configfs_macros.h | 147 ++++++++++++++++++++++++++++++++++++++
1 files changed, 147 insertions(+), 0 deletions(-)
create mode 100644 include/target/configfs_macros.h
diff --git a/include/target/configfs_macros.h b/include/target/configfs_macros.h
new file mode 100644
index 0000000..7fe7460
--- /dev/null
+++ b/include/target/configfs_macros.h
@@ -0,0 +1,147 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * configfs_macros.h - extends macros for configfs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ *
+ * Based on sysfs:
+ * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
+ *
+ * Based on kobject.h:
+ * Copyright (c) 2002-2003 Patrick Mochel
+ * Copyright (c) 2002-2003 Open Source Development Labs
+ *
+ * configfs Copyright (C) 2005 Oracle. All rights reserved.
+ *
+ * Added CONFIGFS_EATTR() macros from original configfs.h macros
+ * Copright (C) 2008-2009 Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
+ *
+ * Please read Documentation/filesystems/configfs.txt before using the
+ * configfs interface, ESPECIALLY the parts about reference counts and
+ * item destructors.
+ */
+
+#ifndef _CONFIGFS_MACROS_H_
+#define _CONFIGFS_MACROS_H_
+
+#include <linux/configfs.h>
+
+/*
+ * Users often need to create attribute structures for their configurable
+ * attributes, containing a configfs_attribute member and function pointers
+ * for the show() and store() operations on that attribute. If they don't
+ * need anything else on the extended attribute structure, they can use
+ * this macro to define it. The argument _name isends up as
+ * 'struct _name_attribute, as well as names of to CONFIGFS_ATTR_OPS() below.
+ * The argument _item is the name of the structure containing the
+ * struct config_item or struct config_group structure members
+ */
+#define CONFIGFS_EATTR_STRUCT(_name, _item) \
+struct _name##_attribute { \
+ struct configfs_attribute attr; \
+ ssize_t (*show)(struct _item *, char *); \
+ ssize_t (*store)(struct _item *, const char *, size_t); \
+}
+
+/*
+ * With the extended attribute structure, users can use this macro
+ * (similar to sysfs' __ATTR) to make defining attributes easier.
+ * An example:
+ * #define MYITEM_EATTR(_name, _mode, _show, _store) \
+ * struct myitem_attribute childless_attr_##_name = \
+ * __CONFIGFS_EATTR(_name, _mode, _show, _store)
+ */
+#define __CONFIGFS_EATTR(_name, _mode, _show, _store) \
+{ \
+ .attr = { \
+ .ca_name = __stringify(_name), \
+ .ca_mode = _mode, \
+ .ca_owner = THIS_MODULE, \
+ }, \
+ .show = _show, \
+ .store = _store, \
+}
+/* Here is a readonly version, only requiring a show() operation */
+#define __CONFIGFS_EATTR_RO(_name, _show) \
+{ \
+ .attr = { \
+ .ca_name = __stringify(_name), \
+ .ca_mode = 0444, \
+ .ca_owner = THIS_MODULE, \
+ }, \
+ .show = _show, \
+}
+
+/*
+ * With these extended attributes, the simple show_attribute() and
+ * store_attribute() operations need to call the show() and store() of the
+ * attributes. This is a common pattern, so we provide a macro to define
+ * them. The argument _name is the name of the attribute defined by
+ * CONFIGFS_ATTR_STRUCT(). The argument _item is the name of the structure
+ * containing the struct config_item or struct config_group structure member.
+ * The argument _item_member is the actual name of the struct config_* struct
+ * in your _item structure. Meaning my_structure->some_config_group.
+ * ^^_item^^^^^ ^^_item_member^^^
+ * This macro expects the attributes to be named "struct <name>_attribute".
+ */
+#define CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member) \
+static struct _item *to_##_name(struct config_item *ci) \
+{ \
+ return (ci) ? container_of(to_config_group(ci), struct _item, \
+ _item_member) : NULL; \
+}
+
+#define CONFIGFS_EATTR_OPS_SHOW(_name, _item) \
+static ssize_t _name##_attr_show(struct config_item *item, \
+ struct configfs_attribute *attr, \
+ char *page) \
+{ \
+ struct _item *_item = to_##_name(item); \
+ struct _name##_attribute * _name##_attr = \
+ container_of(attr, struct _name##_attribute, attr); \
+ ssize_t ret = 0; \
+ \
+ if (_name##_attr->show) \
+ ret = _name##_attr->show(_item, page); \
+ return ret; \
+}
+
+#define CONFIGFS_EATTR_OPS_STORE(_name, _item) \
+static ssize_t _name##_attr_store(struct config_item *item, \
+ struct configfs_attribute *attr, \
+ const char *page, size_t count) \
+{ \
+ struct _item *_item = to_##_name(item); \
+ struct _name##_attribute * _name##_attr = \
+ container_of(attr, struct _name##_attribute, attr); \
+ ssize_t ret = -EINVAL; \
+ \
+ if (_name##_attr->store) \
+ ret = _name##_attr->store(_item, page, count); \
+ return ret; \
+}
+
+#define CONFIGFS_EATTR_OPS(_name, _item, _item_member) \
+ CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member); \
+ CONFIGFS_EATTR_OPS_SHOW(_name, _item); \
+ CONFIGFS_EATTR_OPS_STORE(_name, _item);
+
+#define CONFIGFS_EATTR_OPS_RO(_name, _item, _item_member) \
+ CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member); \
+ CONFIGFS_EATTR_OPS_SHOW(_name, _item);
+
+#endif /* _CONFIGFS_MACROS_H_ */
--
1.7.2.2
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