target: Add target_core_backend_configfs.h helper macros

This patch adds a number of configfs e-attr macros following
what existing target_core_configfs.c code does for internal
target_backend_dev_attrib setup, and similar to how target
fabric drivers allow for external config_item_type + cit->ct_attrs.
assignment.

This is useful for backend drivers like PSCSI who need to only
expose a small subset of device attributes, while still retaining
a default list of attributes for other backend drivers like
IBLOCK, FILEIO, RAMDISK, and TCMU.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2014-11-27 18:57:27 -08:00
parent d23ab570bc
commit 7a23f890b7

View File

@ -0,0 +1,53 @@
#ifndef TARGET_CORE_BACKEND_CONFIGFS_H
#define TARGET_CORE_BACKEND_CONFIGFS_H
#include <target/configfs_macros.h>
#define DEF_TB_DEV_ATTRIB_SHOW(_backend, _name) \
static ssize_t _backend##_dev_show_attr_##_name( \
struct se_dev_attrib *da, \
char *page) \
{ \
return snprintf(page, PAGE_SIZE, "%u\n", \
(u32)da->da_dev->dev_attrib._name); \
}
#define DEF_TB_DEV_ATTRIB_STORE(_backend, _name) \
static ssize_t _backend##_dev_store_attr_##_name( \
struct se_dev_attrib *da, \
const char *page, \
size_t count) \
{ \
unsigned long val; \
int ret; \
\
ret = kstrtoul(page, 0, &val); \
if (ret < 0) { \
pr_err("kstrtoul() failed with ret: %d\n", ret); \
return -EINVAL; \
} \
ret = se_dev_set_##_name(da->da_dev, (u32)val); \
\
return (!ret) ? count : -EINVAL; \
}
#define DEF_TB_DEV_ATTRIB(_backend, _name) \
DEF_TB_DEV_ATTRIB_SHOW(_backend, _name); \
DEF_TB_DEV_ATTRIB_STORE(_backend, _name);
#define DEF_TB_DEV_ATTRIB_RO(_backend, name) \
DEF_TB_DEV_ATTRIB_SHOW(_backend, name);
CONFIGFS_EATTR_STRUCT(target_backend_dev_attrib, se_dev_attrib);
#define TB_DEV_ATTR(_backend, _name, _mode) \
static struct target_backend_dev_attrib_attribute _backend##_dev_attrib_##_name = \
__CONFIGFS_EATTR(_name, _mode, \
_backend##_dev_show_attr_##_name, \
_backend##_dev_store_attr_##_name);
#define TB_DEV_ATTR_RO(_backend, _name) \
static struct target_backend_dev_attrib_attribute _backend##_dev_attrib_##_name = \
__CONFIGFS_EATTR_RO(_name, \
_backend##_dev_show_attr_##_name);
#endif /* TARGET_CORE_BACKEND_CONFIGFS_H */