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

John Johansen
2023-03-02T22:56:33Z

On 3/2/23 12:28, Luis Chamberlain wrote:
> 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>

Reviewed-by: John Johansen <john.johansen@canonical.com>

> ---
> 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;