Subject: Re: [PATCH v2 6/8] inotify: simplify subdirectory registration with register_sysctl()

From: Jan Kara <[email-masked]>
Date: Wed, 24 Nov 2021 10:44:09 +0100

On Tue 23-11-21 12:24:20, Luis Chamberlain wrote:
> From: Xiaoming Ni <[email-masked]>
> 
> There is no need to user boiler plate code to specify a set of base
> directories we're going to stuff sysctls under. Simplify this by using
> register_sysctl() and specifying the directory path directly.
> 
> Move inotify_user sysctl to inotify_user.c while at it to remove clutter
> from kernel/sysctl.c.
> 
> Signed-off-by: Xiaoming Ni <[email-masked]>
> [mcgrof: update commit log to reflect new path we decided to take]
> Signed-off-by: Luis Chamberlain <[email-masked]>

This looks fishy. You register inotify_table but not fanotify_table and
remove both...

								Honza

> ---
>  fs/notify/inotify/inotify_user.c | 11 ++++++++++-
>  include/linux/inotify.h          |  3 ---
>  kernel/sysctl.c                  | 21 ---------------------
>  3 files changed, 10 insertions(+), 25 deletions(-)
> 
> diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
> index 29fca3284bb5..54583f62dc44 100644
> --- a/fs/notify/inotify/inotify_user.c
> +++ b/fs/notify/inotify/inotify_user.c
> @@ -58,7 +58,7 @@ struct kmem_cache *inotify_inode_mark_cachep __read_mostly;
>  static long it_zero = 0;
>  static long it_int_max = INT_MAX;
>  
> -struct ctl_table inotify_table[] = {
> +static struct ctl_table inotify_table[] = {
>  	{
>  		.procname	= "max_user_instances",
>  		.data		= &init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES],
> @@ -87,6 +87,14 @@ struct ctl_table inotify_table[] = {
>  	},
>  	{ }
>  };
> +
> +static void __init inotify_sysctls_init(void)
> +{
> +	register_sysctl("fs/inotify", inotify_table);
> +}
> +
> +#else
> +#define inotify_sysctls_init() do { } while (0)
>  #endif /* CONFIG_SYSCTL */
>  
>  static inline __u32 inotify_arg_to_mask(struct inode *inode, u32 arg)
> @@ -849,6 +857,7 @@ static int __init inotify_user_setup(void)
>  	inotify_max_queued_events = 16384;
>  	init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES] = 128;
>  	init_user_ns.ucount_max[UCOUNT_INOTIFY_WATCHES] = watches_max;
> +	inotify_sysctls_init();
>  
>  	return 0;
>  }
> diff --git a/include/linux/inotify.h b/include/linux/inotify.h
> index 6a24905f6e1e..8d20caa1b268 100644
> --- a/include/linux/inotify.h
> +++ b/include/linux/inotify.h
> @@ -7,11 +7,8 @@
>  #ifndef _LINUX_INOTIFY_H
>  #define _LINUX_INOTIFY_H
>  
> -#include <linux/sysctl.h>
>  #include <uapi/linux/inotify.h>
>  
> -extern struct ctl_table inotify_table[]; /* for sysctl */
> -
>  #define ALL_INOTIFY_BITS (IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
>  			  IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \
>  			  IN_MOVED_TO | IN_CREATE | IN_DELETE | \
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 7a90a12b9ea4..6aa67c737e4e 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -125,13 +125,6 @@ static const int maxolduid = 65535;
>  static const int ngroups_max = NGROUPS_MAX;
>  static const int cap_last_cap = CAP_LAST_CAP;
>  
> -#ifdef CONFIG_INOTIFY_USER
> -#include <linux/inotify.h>
> -#endif
> -#ifdef CONFIG_FANOTIFY
> -#include <linux/fanotify.h>
> -#endif
> -
>  #ifdef CONFIG_PROC_SYSCTL
>  
>  /**
> @@ -3099,20 +3092,6 @@ static struct ctl_table fs_table[] = {
>  		.proc_handler	= proc_dointvec,
>  	},
>  #endif
> -#ifdef CONFIG_INOTIFY_USER
> -	{
> -		.procname	= "inotify",
> -		.mode		= 0555,
> -		.child		= inotify_table,
> -	},
> -#endif
> -#ifdef CONFIG_FANOTIFY
> -	{
> -		.procname	= "fanotify",
> -		.mode		= 0555,
> -		.child		= fanotify_table,
> -	},
> -#endif
>  #ifdef CONFIG_EPOLL
>  	{
>  		.procname	= "epoll",
> -- 
> 2.33.0
> 
-- 
Jan Kara <[email-masked]>
SUSE Labs, CR