staging/lustre/obdclass: move sysctl timeout to sysfs

This is the first step of moving lustre sysctls from
/proc/sys/lustre to /sys/fs/lustre
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/obd_class.h

@@ -1869,8 +1869,8 @@ extern int (*ptlrpc_put_connection_superhack)(struct ptlrpc_connection *c);
 /* obd_mount.c */
 
 /* sysctl.c */
-extern void obd_sysctl_init (void);
-extern void obd_sysctl_clean (void);
+extern int obd_sysctl_init(void);
+extern void obd_sysctl_clean(void);
 
 /* uuid.c  */
 typedef __u8 class_uuid_t[16];

drivers/staging/lustre/lustre/obdclass/class_obd.c

@@ -567,12 +567,14 @@ static int __init init_obdclass(void)
 	if (err)
 		return err;
 
-	obd_sysctl_init();
-
 	err = class_procfs_init();
 	if (err)
 		return err;
 
+	err = obd_sysctl_init();
+	if (err)
+		return err;
+
 	err = lu_global_init();
 	if (err)
 		return err;

drivers/staging/lustre/lustre/obdclass/linux/linux-sysctl.c

@@ -54,16 +54,53 @@
 static struct ctl_table_header *obd_table_header;
 #endif
 
-#ifdef CONFIG_SYSCTL
-static int proc_set_timeout(struct ctl_table *table, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+struct static_lustre_uintvalue_attr {
+	struct {
+		struct attribute attr;
+		ssize_t (*show)(struct kobject *kobj, struct attribute *attr,
+				char *buf);
+		ssize_t (*store)(struct kobject *kobj, struct attribute *attr,
+				 const char *buf, size_t len);
+	} u;
+	int *value;
+};
+
+static ssize_t static_uintvalue_show(struct kobject *kobj,
+				    struct attribute *attr,
+				    char *buf)
 {
+	struct static_lustre_uintvalue_attr *lattr = (void *)attr;
+
+	return sprintf(buf, "%d\n", *lattr->value);
+}
+
+static ssize_t static_uintvalue_store(struct kobject *kobj,
+				     struct attribute *attr,
+				     const char *buffer, size_t count)
+{
+	struct static_lustre_uintvalue_attr *lattr  = (void *)attr;
 	int rc;
+	unsigned int val;
 
-	rc = proc_dointvec(table, write, buffer, lenp, ppos);
-	return rc;
+	rc = kstrtouint(buffer, 10, &val);
+	if (rc)
+		return rc;
+
+	*lattr->value = val;
+
+	return count;
 }
 
+#define LUSTRE_STATIC_UINT_ATTR(name, value) \
+static struct static_lustre_uintvalue_attr lustre_sattr_##name =	\
+					{__ATTR(name, 0644,		\
+						static_uintvalue_show,	\
+						static_uintvalue_store),\
+					  value }
+
+LUSTRE_STATIC_UINT_ATTR(timeout, &obd_timeout);
+
+#ifdef CONFIG_SYSCTL
 static int proc_max_dirty_pages_in_mb(struct ctl_table *table, int write,
 			       void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -106,13 +143,6 @@ static int proc_max_dirty_pages_in_mb(struct ctl_table *table, int write,
 }
 
 static struct ctl_table obd_table[] = {
-	{
-		.procname = "timeout",
-		.data     = &obd_timeout,
-		.maxlen   = sizeof(int),
-		.mode     = 0644,
-		.proc_handler = &proc_set_timeout
-	},
 	{
 		.procname = "debug_peer_on_timeout",
 		.data     = &obd_debug_peer_on_timeout,
@@ -191,12 +221,22 @@ static struct ctl_table parent_table[] = {
 };
 #endif
 
-void obd_sysctl_init(void)
+static struct attribute *lustre_attrs[] = {
+	&lustre_sattr_timeout.u.attr,
+	NULL,
+};
+
+static struct attribute_group lustre_attr_group = {
+	.attrs = lustre_attrs,
+};
+
+int obd_sysctl_init(void)
 {
 #ifdef CONFIG_SYSCTL
 	if (!obd_table_header)
 		obd_table_header = register_sysctl_table(parent_table);
 #endif
+	return sysfs_create_group(lustre_kobj, &lustre_attr_group);
 }
 
 void obd_sysctl_clean(void)

drivers/staging/lustre/sysfs-fs-lustre

@@ -40,6 +40,18 @@ Description:
 			       e.g. dd.1253
 		nodelocal - use jobid_name value from above.
 
+What:		/sys/fs/lustre/timeout
+Date:		June 2015
+Contact:	"Oleg Drokin" <oleg.drokin@intel.com>
+Description:
+		Controls "lustre timeout" variable, also known as obd_timeout
+		in some old manual. In the past obd_timeout was of paramount
+		importance as the timeout value used everywhere and where
+		other timeouts were derived from. These days it's much less
+		important as network timeouts are mostly determined by
+		AT (adaptive timeouts).
+		Unit: seconds, default: 100
+
 What:		/sys/fs/lustre/llite/<fsname>-<uuid>/blocksize
 Date:		May 2015
 Contact:	"Oleg Drokin" <oleg.drokin@intel.com>