[PATCH 02/11] proc_sysctl: move helper which creates required subdirectories

Luis Chamberlain
2023-03-02T20:29:11Z

Move the code which creates the subdirectories for a ctl table
into a helper routine so to make it easier to review. Document
the goal.

This creates no functional changes.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
fs/proc/proc_sysctl.c | 56 ++++++++++++++++++++++++-------------------
1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 1df0beb50dbe..6b9b2694d430 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1283,6 +1283,35 @@ static int insert_links(struct ctl_table_header *head)
return err;
}

+/* Find the directory for the ctl_table. If one is not found create it. */
+static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path)
+{
+ const char *name, *nextname;
+
+ for (name = path; name; name = nextname) {
+ int namelen;
+ nextname = strchr(name, '/');
+ if (nextname) {
+ namelen = nextname - name;
+ nextname++;
+ } else {
+ namelen = strlen(name);
+ }
+ if (namelen == 0)
+ continue;
+
+ /*
+ * namelen ensures if name is "foo/bar/yay" only foo is
+ * registered first. We traverse as if using mkdir -p and
+ * return a ctl_dir for the last directory entry.
+ */
+ dir = get_subdir(dir, name, namelen);
+ if (IS_ERR(dir))
+ break;
+ }
+ return dir;
+}
+
/**
* __register_sysctl_table - register a leaf sysctl table
* @set: Sysctl tree to register on
@@ -1334,7 +1363,6 @@ struct ctl_table_header *__register_sysctl_table(
{
struct ctl_table_root *root = set->dir.header.root;
struct ctl_table_header *header;
- const char *name, *nextname;
struct ctl_dir *dir;
struct ctl_table *entry;
struct ctl_node *node;
@@ -1359,29 +1387,9 @@ struct ctl_table_header *__register_sysctl_table(
dir->header.nreg++;
spin_unlock(&sysctl_lock);

- /* Find the directory for the ctl_table */
- for (name = path; name; name = nextname) {
- int namelen;
- nextname = strchr(name, '/');
- if (nextname) {
- namelen = nextname - name;
- nextname++;
- } else {
- namelen = strlen(name);
- }
- if (namelen == 0)
- continue;
-
- /*
- * namelen ensures if name is "foo/bar/yay" only foo is
- * registered first. We traverse as if using mkdir -p and
- * return a ctl_dir for the last directory entry.
- */
- dir = get_subdir(dir, name, namelen);
- if (IS_ERR(dir))
- goto fail;
- }
-
+ dir = sysctl_mkdir_p(dir, path);
+ if (IS_ERR(dir))
+ goto fail;
spin_lock(&sysctl_lock);
if (insert_header(dir, header))
goto fail_put_dir_locked;
--
2.39.1