[PATCH v4 8/8] sysctl: Remove register_sysctl_table

[Joel Granados]

This is part of the general push to deprecate register_sysctl_paths and
register_sysctl_table. After removing all the calling functions, we
remove both the register_sysctl_table function and the documentation
check that appeared in check-sysctl-docs awk script.

We save 595 bytes with this change:

./scripts/bloat-o-meter vmlinux.1.refactor-base-paths vmlinux.2.remove-sysctl-table
add/remove: 2/8 grow/shrink: 1/0 up/down: 1154/-1749 (-595)
Function                                     old     new   delta
count_subheaders                               -     983    +983
unregister_sysctl_table                       29     184    +155
__pfx_count_subheaders                         -      16     +16
__pfx_unregister_sysctl_table.part            16       -     -16
__pfx_register_leaf_sysctl_tables.constprop   16       -     -16
__pfx_count_subheaders.part                   16       -     -16
__pfx___register_sysctl_base                  16       -     -16
unregister_sysctl_table.part                 136       -    -136
__register_sysctl_base                       478       -    -478
register_leaf_sysctl_tables.constprop        524       -    -524
count_subheaders.part                        547       -    -547
Total: Before=21257652, After=21257057, chg -0.00%

Signed-off-by: Joel Granados <j.granados@xxxxxxxxxxx>
[mcgrof: remove register_leaf_sysctl_tables and append_path too and
 add bloat-o-meter stats]
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
 fs/proc/proc_sysctl.c     | 159 --------------------------------------
 scripts/check-sysctl-docs |  10 ---
 2 files changed, 169 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index f8f19e000d76..8873812d22f3 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1466,19 +1466,6 @@ void __init __register_sysctl_init(const char *path, struct ctl_table *table,
 	kmemleak_not_leak(hdr);
 }
 
-static char *append_path(const char *path, char *pos, const char *name)
-{
-	int namelen;
-	namelen = strlen(name);
-	if (((pos - path) + namelen + 2) >= PATH_MAX)
-		return NULL;
-	memcpy(pos, name, namelen);
-	pos[namelen] = '/';
-	pos[namelen + 1] = '\0';
-	pos += namelen + 1;
-	return pos;
-}
-
 static int count_subheaders(struct ctl_table *table)
 {
 	int has_files = 0;
@@ -1498,152 +1485,6 @@ static int count_subheaders(struct ctl_table *table)
 	return nr_subheaders + has_files;
 }
 
-static int register_leaf_sysctl_tables(const char *path, char *pos,
-	struct ctl_table_header ***subheader, struct ctl_table_set *set,
-	struct ctl_table *table)
-{
-	struct ctl_table *ctl_table_arg = NULL;
-	struct ctl_table *entry, *files;
-	int nr_files = 0;
-	int nr_dirs = 0;
-	int err = -ENOMEM;
-
-	list_for_each_table_entry(entry, table) {
-		if (entry->child)
-			nr_dirs++;
-		else
-			nr_files++;
-	}
-
-	files = table;
-	/* If there are mixed files and directories we need a new table */
-	if (nr_dirs && nr_files) {
-		struct ctl_table *new;
-		files = kcalloc(nr_files + 1, sizeof(struct ctl_table),
-				GFP_KERNEL);
-		if (!files)
-			goto out;
-
-		ctl_table_arg = files;
-		new = files;
-
-		list_for_each_table_entry(entry, table) {
-			if (entry->child)
-				continue;
-			*new = *entry;
-			new++;
-		}
-	}
-
-	/* Register everything except a directory full of subdirectories */
-	if (nr_files || !nr_dirs) {
-		struct ctl_table_header *header;
-		header = __register_sysctl_table(set, path, files);
-		if (!header) {
-			kfree(ctl_table_arg);
-			goto out;
-		}
-
-		/* Remember if we need to free the file table */
-		header->ctl_table_arg = ctl_table_arg;
-		**subheader = header;
-		(*subheader)++;
-	}
-
-	/* Recurse into the subdirectories. */
-	list_for_each_table_entry(entry, table) {
-		char *child_pos;
-
-		if (!entry->child)
-			continue;
-
-		err = -ENAMETOOLONG;
-		child_pos = append_path(path, pos, entry->procname);
-		if (!child_pos)
-			goto out;
-
-		err = register_leaf_sysctl_tables(path, child_pos, subheader,
-						  set, entry->child);
-		pos[0] = '\0';
-		if (err)
-			goto out;
-	}
-	err = 0;
-out:
-	/* On failure our caller will unregister all registered subheaders */
-	return err;
-}
-
-/**
- * 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.
- * We are slowly deprecating this call so avoid its use.
- */
-static struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
-{
-	struct ctl_table *ctl_table_arg = table;
-	int nr_subheaders = count_subheaders(table);
-	struct ctl_table_header *header = NULL, **subheaders, **subheader;
-	char *new_path, *pos;
-
-	pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL);
-	if (!new_path)
-		return NULL;
-
-	pos[0] = '\0';
-	while (table->procname && table->child && !table[1].procname) {
-		pos = append_path(new_path, pos, table->procname);
-		if (!pos)
-			goto out;
-		table = table->child;
-	}
-	if (nr_subheaders == 1) {
-		header = __register_sysctl_table(&sysctl_table_root.default_set, new_path, table);
-		if (header)
-			header->ctl_table_arg = ctl_table_arg;
-	} else {
-		header = kzalloc(sizeof(*header) +
-				 sizeof(*subheaders)*nr_subheaders, GFP_KERNEL);
-		if (!header)
-			goto out;
-
-		subheaders = (struct ctl_table_header **) (header + 1);
-		subheader = subheaders;
-		header->ctl_table_arg = ctl_table_arg;
-
-		if (register_leaf_sysctl_tables(new_path, pos, &subheader,
-						&sysctl_table_root.default_set, table))
-			goto err_register_leaves;
-	}
-
-out:
-	kfree(new_path);
-	return header;
-
-err_register_leaves:
-	while (subheader > subheaders) {
-		struct ctl_table_header *subh = *(--subheader);
-		struct ctl_table *table = subh->ctl_table_arg;
-		unregister_sysctl_table(subh);
-		kfree(table);
-	}
-	kfree(header);
-	header = NULL;
-	goto out;
-}
-
-int __register_sysctl_base(struct ctl_table *base_table)
-{
-	struct ctl_table_header *hdr;
-
-	hdr = register_sysctl_table(base_table);
-	kmemleak_not_leak(hdr);
-	return 0;
-}
-
 static void put_links(struct ctl_table_header *header)
 {
 	struct ctl_table_set *root_set = &sysctl_table_root.default_set;
diff --git a/scripts/check-sysctl-docs b/scripts/check-sysctl-docs
index edc9a629d79e..4f163e0bf6a4 100755
--- a/scripts/check-sysctl-docs
+++ b/scripts/check-sysctl-docs
@@ -146,16 +146,6 @@ curtable && /\.procname[\t ]*=[\t ]*".+"/ {
     children[curtable][curentry] = child
 }
 
-/register_sysctl_table\(.*\)/ {
-    match($0, /register_sysctl_table\(([^)]+)\)/, tables)
-    if (debug) print "Registering table " tables[1]
-    if (children[tables[1]][table]) {
-	for (entry in entries[children[tables[1]][table]]) {
-	    printentry(entry)
-	}
-    }
-}
-
 END {
     for (entry in documented) {
 	if (!seen[entry]) {
-- 
2.30.2