From d398249022d3de2bffb8cb0120c88bc6f926d3bf Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Fri, 30 Nov 2007 23:50:18 +1100
Subject: [PATCH] --- yaml --- r: 78229 b: refs/heads/master c:
 29e796fd4de54b8f5bc30d897611210ece4fd0f2 h: refs/heads/master i:   78227:
 483209ac6b989b920d171a85ea6948e8965c3291 v: v3

---
 [refs]                       |  2 +-
 trunk/include/linux/sysctl.h |  8 ++++
 trunk/kernel/sysctl.c        | 89 ++++++++++++++++++++++++++++++------
 3 files changed, 83 insertions(+), 16 deletions(-)

diff --git a/[refs] b/[refs]
index 15b039c10909..aeb0b303a904 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: be0ea7d5da3d99140bde7e5cea328eb111731700
+refs/heads/master: 29e796fd4de54b8f5bc30d897611210ece4fd0f2
diff --git a/trunk/include/linux/sysctl.h b/trunk/include/linux/sysctl.h
index 4f5047df8a9e..3b6e2c9fbb2e 100644
--- a/trunk/include/linux/sysctl.h
+++ b/trunk/include/linux/sysctl.h
@@ -1059,7 +1059,15 @@ struct ctl_table_header
 	struct completion *unregistering;
 };
 
+/* struct ctl_path describes where in the hierarchy a table is added */
+struct ctl_path {
+	const char *procname;
+	int ctl_name;
+};
+
 struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
+struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
+						struct ctl_table *table);
 
 void unregister_sysctl_table(struct ctl_table_header * table);
 int sysctl_check_table(struct ctl_table *table);
diff --git a/trunk/kernel/sysctl.c b/trunk/kernel/sysctl.c
index 8e96558cb8f3..f580542333eb 100644
--- a/trunk/kernel/sysctl.c
+++ b/trunk/kernel/sysctl.c
@@ -1561,11 +1561,12 @@ static __init int sysctl_init(void)
 core_initcall(sysctl_init);
 
 /**
- * register_sysctl_table - register a sysctl hierarchy
+ * register_sysctl_paths - register a sysctl hierarchy
+ * @path: The path to the directory the sysctl table is in.
  * @table: the top-level table structure
  *
  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
- * array. An entry with a ctl_name of 0 terminates the table. 
+ * array. A completely 0 filled entry terminates the table.
  *
  * The members of the &struct ctl_table structure are used as follows:
  *
@@ -1628,25 +1629,76 @@ core_initcall(sysctl_init);
  * This routine returns %NULL on a failure to register, and a pointer
  * to the table header on success.
  */
-struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
+struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
+						struct ctl_table *table)
 {
-	struct ctl_table_header *tmp;
-	tmp = kmalloc(sizeof(struct ctl_table_header), GFP_KERNEL);
-	if (!tmp)
+	struct ctl_table_header *header;
+	struct ctl_table *new, **prevp;
+	unsigned int n, npath;
+
+	/* Count the path components */
+	for (npath = 0; path[npath].ctl_name || path[npath].procname; ++npath)
+		;
+
+	/*
+	 * For each path component, allocate a 2-element ctl_table array.
+	 * The first array element will be filled with the sysctl entry
+	 * for this, the second will be the sentinel (ctl_name == 0).
+	 *
+	 * We allocate everything in one go so that we don't have to
+	 * worry about freeing additional memory in unregister_sysctl_table.
+	 */
+	header = kzalloc(sizeof(struct ctl_table_header) +
+			 (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
+	if (!header)
 		return NULL;
-	tmp->ctl_table = table;
-	INIT_LIST_HEAD(&tmp->ctl_entry);
-	tmp->used = 0;
-	tmp->unregistering = NULL;
-	sysctl_set_parent(NULL, table);
-	if (sysctl_check_table(tmp->ctl_table)) {
-		kfree(tmp);
+
+	new = (struct ctl_table *) (header + 1);
+
+	/* Now connect the dots */
+	prevp = &header->ctl_table;
+	for (n = 0; n < npath; ++n, ++path) {
+		/* Copy the procname */
+		new->procname = path->procname;
+		new->ctl_name = path->ctl_name;
+		new->mode     = 0555;
+
+		*prevp = new;
+		prevp = &new->child;
+
+		new += 2;
+	}
+	*prevp = table;
+
+	INIT_LIST_HEAD(&header->ctl_entry);
+	header->used = 0;
+	header->unregistering = NULL;
+	sysctl_set_parent(NULL, header->ctl_table);
+	if (sysctl_check_table(header->ctl_table)) {
+		kfree(header);
 		return NULL;
 	}
 	spin_lock(&sysctl_lock);
-	list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
+	list_add_tail(&header->ctl_entry, &root_table_header.ctl_entry);
 	spin_unlock(&sysctl_lock);
-	return tmp;
+
+	return header;
+}
+
+/**
+ * register_sysctl_table - register a sysctl table hierarchy
+ * @table: the top-level table structure
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * See register_sysctl_paths for more details.
+ */
+struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
+{
+	static const struct ctl_path null_path[] = { {} };
+
+	return register_sysctl_paths(null_path, table);
 }
 
 /**
@@ -1675,6 +1727,12 @@ struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
 	return NULL;
 }
 
+struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
+						    struct ctl_table *table)
+{
+	return NULL;
+}
+
 void unregister_sysctl_table(struct ctl_table_header * table)
 {
 }
@@ -2733,6 +2791,7 @@ EXPORT_SYMBOL(proc_dostring);
 EXPORT_SYMBOL(proc_doulongvec_minmax);
 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
 EXPORT_SYMBOL(register_sysctl_table);
+EXPORT_SYMBOL(register_sysctl_paths);
 EXPORT_SYMBOL(sysctl_intvec);
 EXPORT_SYMBOL(sysctl_jiffies);
 EXPORT_SYMBOL(sysctl_ms_jiffies);