diff options
| -rw-r--r-- | fs/sysfs/file.c | 27 | ||||
| -rw-r--r-- | include/linux/sysfs.h | 15 |
2 files changed, 42 insertions, 0 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 6b7652fb8050..289b57d32c89 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -783,3 +783,30 @@ int sysfs_emit_at(char *buf, int at, const char *fmt, ...) return len; } EXPORT_SYMBOL_GPL(sysfs_emit_at); + +/** + * sysfs_bin_attr_simple_read - read callback to simply copy from memory. + * @file: attribute file which is being read. + * @kobj: object to which the attribute belongs. + * @attr: attribute descriptor. + * @buf: destination buffer. + * @off: offset in bytes from which to read. + * @count: maximum number of bytes to read. + * + * Simple ->read() callback for bin_attributes backed by a buffer in memory. + * The @private and @size members in struct bin_attribute must be set to the + * buffer's location and size before the bin_attribute is created in sysfs. + * + * Bounds check for @off and @count is done in sysfs_kf_bin_read(). + * Negative value check for @off is done in vfs_setpos() and default_llseek(). + * + * Returns number of bytes written to @buf. + */ +ssize_t sysfs_bin_attr_simple_read(struct file *file, struct kobject *kobj, + struct bin_attribute *attr, char *buf, + loff_t off, size_t count) +{ + memcpy(buf, attr->private + off, count); + return count; +} +EXPORT_SYMBOL_GPL(sysfs_bin_attr_simple_read); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 326341c62385..a7d725fbf739 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -371,6 +371,17 @@ struct bin_attribute bin_attr_##_name = __BIN_ATTR_ADMIN_RO(_name, _size) #define BIN_ATTR_ADMIN_RW(_name, _size) \ struct bin_attribute bin_attr_##_name = __BIN_ATTR_ADMIN_RW(_name, _size) +#define __BIN_ATTR_SIMPLE_RO(_name, _mode) { \ + .attr = { .name = __stringify(_name), .mode = _mode }, \ + .read = sysfs_bin_attr_simple_read, \ +} + +#define BIN_ATTR_SIMPLE_RO(_name) \ +struct bin_attribute bin_attr_##_name = __BIN_ATTR_SIMPLE_RO(_name, 0444) + +#define BIN_ATTR_SIMPLE_ADMIN_RO(_name) \ +struct bin_attribute bin_attr_##_name = __BIN_ATTR_SIMPLE_RO(_name, 0400) + struct sysfs_ops { ssize_t (*show)(struct kobject *, struct attribute *, char *); ssize_t (*store)(struct kobject *, struct attribute *, const char *, size_t); @@ -478,6 +489,10 @@ int sysfs_emit(char *buf, const char *fmt, ...); __printf(3, 4) int sysfs_emit_at(char *buf, int at, const char *fmt, ...); +ssize_t sysfs_bin_attr_simple_read(struct file *file, struct kobject *kobj, + struct bin_attribute *attr, char *buf, + loff_t off, size_t count); + #else /* CONFIG_SYSFS */ static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns) |