Subject: Re: [PATCH v2 4/8] ocfs2: simplify subdirectory registration with register_sysctl()

From: Jan Kara <[email-masked]>
Date: Wed, 24 Nov 2021 10:49:06 +0100

On Tue 23-11-21 12:24:18, Luis Chamberlain wrote:
> 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.
> 
> // pycocci sysctl-subdir-register-sysctl-simplify.cocci PATH

Heh, nice example of using Coccinelle. The result looks good. Feel free to
add:

Reviewed-by: Jan Kara <[email-masked]>

								Honza

> 
> @c1@
> expression E1;
> identifier subdir, sysctls;
> @@
> 
> static struct ctl_table subdir[] = {
> 	{
> 		.procname = E1,
> 		.maxlen = 0,
> 		.mode = 0555,
> 		.child = sysctls,
> 	},
> 	{ }
> };
> 
> @c2@
> identifier c1.subdir;
> 
> expression E2;
> identifier base;
> @@
> 
> static struct ctl_table base[] = {
> 	{
> 		.procname = E2,
> 		.maxlen = 0,
> 		.mode = 0555,
> 		.child = subdir,
> 	},
> 	{ }
> };
> 
> @c3@
> identifier c2.base;
> identifier header;
> @@
> 
> header = register_sysctl_table(base);
> 
> @r1 depends on c1 && c2 && c3@
> expression c1.E1;
> identifier c1.subdir, c1.sysctls;
> @@
> 
> -static struct ctl_table subdir[] = {
> -	{
> -		.procname = E1,
> -		.maxlen = 0,
> -		.mode = 0555,
> -		.child = sysctls,
> -	},
> -	{ }
> -};
> 
> @r2 depends on c1 && c2 && c3@
> identifier c1.subdir;
> 
> expression c2.E2;
> identifier c2.base;
> @@
> -static struct ctl_table base[] = {
> -	{
> -		.procname = E2,
> -		.maxlen = 0,
> -		.mode = 0555,
> -		.child = subdir,
> -	},
> -	{ }
> -};
> 
> @initialize:python@
> @@
> 
> def make_my_fresh_expression(s1, s2):
>   return '"' + s1.strip('"') + "/" + s2.strip('"') + '"'
> 
> @r3 depends on c1 && c2 && c3@
> expression c1.E1;
> identifier c1.sysctls;
> expression c2.E2;
> identifier c2.base;
> identifier c3.header;
> fresh identifier E3 = script:python(E2, E1) { make_my_fresh_expression(E2, E1) };
> @@
> 
> header =
> -register_sysctl_table(base);
> +register_sysctl(E3, sysctls);
> 
> Generated-by: Coccinelle SmPL
> Signed-off-by: Luis Chamberlain <[email-masked]>
> ---
>  fs/ocfs2/stackglue.c | 25 +------------------------
>  1 file changed, 1 insertion(+), 24 deletions(-)
> 
> diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
> index 16f1bfc407f2..731558a6f27d 100644
> --- a/fs/ocfs2/stackglue.c
> +++ b/fs/ocfs2/stackglue.c
> @@ -672,31 +672,8 @@ static struct ctl_table ocfs2_mod_table[] = {
>  	{ }
>  };
>  
> -static struct ctl_table ocfs2_kern_table[] = {
> -	{
> -		.procname	= "ocfs2",
> -		.data		= NULL,
> -		.maxlen		= 0,
> -		.mode		= 0555,
> -		.child		= ocfs2_mod_table
> -	},
> -	{ }
> -};
> -
> -static struct ctl_table ocfs2_root_table[] = {
> -	{
> -		.procname	= "fs",
> -		.data		= NULL,
> -		.maxlen		= 0,
> -		.mode		= 0555,
> -		.child		= ocfs2_kern_table
> -	},
> -	{ }
> -};
> -
>  static struct ctl_table_header *ocfs2_table_header;
>  
> -
>  /*
>   * Initialization
>   */
> @@ -705,7 +682,7 @@ static int __init ocfs2_stack_glue_init(void)
>  {
>  	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
>  
> -	ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
> +	ocfs2_table_header = register_sysctl("fs/ocfs2", ocfs2_mod_table);
>  	if (!ocfs2_table_header) {
>  		printk(KERN_ERR
>  		       "ocfs2 stack glue: unable to register sysctl\n");
> -- 
> 2.33.0
> 
-- 
Jan Kara <[email-masked]>
SUSE Labs, CR