staging/lustre: Generic helpers for sysfs

From: Oleg Drokin <[email protected]>

Add generic helpers to allow displaying oof lustre-specific values in /sys/fs/lustre

Signed-off-by Oleg Drokin <[email protected]>

---
 .../staging/lustre/lustre/include/lprocfs_status.h | 26 ++++++++++++++++++++++
 .../lustre/lustre/obdclass/lprocfs_status.c        | 24 ++++++++++++++++++++
 2 files changed, 50 insertions(+)

drivers/staging/lustre/lustre/include/lprocfs_status.h +26 -0

index d030847..03500a8 100644
@@ -350,6 +350,8 @@ enum {
 /* class_obd.c */
 extern struct proc_dir_entry *proc_lustre_root;
 
+extern struct kobject lustre_kobj;
+
 struct obd_device;
 struct obd_histogram;
 

@@ -742,6 +744,30 @@ static struct file_operations name##_fops = {				\
 		.release = lprocfs_single_release,			\
 	}
 
+struct lustre_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct kobject *kobj, char *);
+	ssize_t (*store)(struct kobject *kobj, const char *, size_t);
+};
+
+#define LUSTRE_ATTR(name, mode, show, store) \
+static struct lustre_attr lustre_attr_##name = __ATTR(name, mode, show, store)
+
+#define LUSTRE_ATTR_VALUE(name, mode, show, store, value) \
+static struct lustre_attr lustre_attr_##name = \
+			{ __ATTR(name, mode, show, store), value }
+
+#define LUSTRE_RO_ATTR(name) LUSTRE_ATTR(name, 0444, name##_show, NULL)
+#define LUSTRE_RW_ATTR(name) LUSTRE_ATTR(name, 0644, name##_show, name##_store)
+#define LUSTRE_ATTR_LIST(name) &lustre_attr_##name.attr
+
+ssize_t lustre_attr_show(struct kobject *kobj,
+			 struct attribute *attr, char *buf);
+ssize_t lustre_attr_store(struct kobject *kobj, struct attribute *attr,
+			 const char *buf, size_t len);
+
+extern const struct sysfs_ops lustre_sysfs_ops;
+
 /* lproc_ptlrpc.c */
 struct ptlrpc_request;
 extern void target_print_req(void *seq_file, struct ptlrpc_request *req);

drivers/staging/lustre/lustre/obdclass/lprocfs_status.c +14 -0

index c171c6c..bdfd652 100644
@@ -2057,3 +2057,27 @@ int lprocfs_obd_rd_max_pages_per_rpc(struct seq_file *m, void *data)
 EXPORT_SYMBOL(lprocfs_obd_rd_max_pages_per_rpc);
 
 #endif
+
+ssize_t lustre_attr_show(struct kobject *kobj,
+			 struct attribute *attr, char *buf)
+{
+	struct lustre_attr *a = container_of(attr, struct lustre_attr, attr);
+
+	return a->show ? a->show(kobj, buf) : 0;
+}
+EXPORT_SYMBOL(lustre_attr_show);
+
+ssize_t lustre_attr_store(struct kobject *kobj, struct attribute *attr,
+			  const char *buf, size_t len)
+{
+	struct lustre_attr *a = container_of(attr, struct lustre_attr, attr);