Subject: Re: [PATCH v3 4/8] cgroup: Remove CGROUP_BUILTIN_SUBSYS_COUNT

From: Tejun Heo <[email-masked]>
Date: Tue, 11 Sep 2012 13:41:55 -0700

Hello, Daniel.

Just one nit.

On Tue, Sep 11, 2012 at 06:26:10PM +0200, Daniel Wagner wrote:
> @@ -4502,10 +4507,13 @@ int __init cgroup_init_early(void)
>  	for (i = 0; i < CSS_SET_TABLE_SIZE; i++)
>  		INIT_HLIST_HEAD(&css_set_table[i]);
>  
> -	/* at bootup time, we don't worry about modular subsystems */
> -	for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
> +	for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
>  		struct cgroup_subsys *ss = subsys[i];
>  
> +		/* at bootup time, we don't worry about modular subsystems */
> +		if (!ss || (ss && ss->module))
> +			continue;
> +

The middle "ss" test is unnecessary.  Control never gets there if
NULL.

> @@ -4538,9 +4546,12 @@ int __init cgroup_init(void)
>  	if (err)
>  		return err;
>  
> -	/* at bootup time, we don't worry about modular subsystems */
> -	for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
> +	for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
>  		struct cgroup_subsys *ss = subsys[i];
> +
> +		/* at bootup time, we don't worry about modular subsystems */
> +		if (!ss || (ss && ss->module))
> +			continue;

Ditto.

> @@ -4735,13 +4746,16 @@ void cgroup_fork_callbacks(struct task_struct *child)
>  {
>  	if (need_forkexit_callback) {
>  		int i;
> -		/*
> -		 * forkexit callbacks are only supported for builtin
> -		 * subsystems, and the builtin section of the subsys array is
> -		 * immutable, so we don't need to lock the subsys array here.
> -		 */
> -		for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
> +		for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
>  			struct cgroup_subsys *ss = subsys[i];
> +
> +			/*
> +			 * forkexit callbacks are only supported for
> +			 * builtin subsystems.
> +			 */
> +			if (!ss || (ss && ss->module))
> +				continue;
> +

Ditto.

> @@ -4846,12 +4860,13 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
>  	tsk->cgroups = &init_css_set;
>  
>  	if (run_callbacks && need_forkexit_callback) {
> -		/*
> -		 * modular subsystems can't use callbacks, so no need to lock
> -		 * the subsys array
> -		 */
> -		for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
> +		for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
>  			struct cgroup_subsys *ss = subsys[i];
> +
> +			/* modular subsystems can't use callbacks */
> +			if (!ss || (ss && ss->module))
> +				continue;
> +

Ditto.

> @@ -5037,13 +5052,17 @@ static int __init cgroup_disable(char *str)
>  	while ((token = strsep(&str, ",")) != NULL) {
>  		if (!*token)
>  			continue;
> -		/*
> -		 * cgroup_disable, being at boot time, can't know about module
> -		 * subsystems, so we don't worry about them.
> -		 */
> -		for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
> +		for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
>  			struct cgroup_subsys *ss = subsys[i];
>  
> +			/*
> +			 * cgroup_disable, being at boot time, can't
> +			 * know about module subsystems, so we don't
> +			 * worry about them.
> +			 */
> +			if (!ss || (ss && ss->module))
> +				continue;
> +

Ditto.

Other than that,

 Acked-by: Tejun Heo <[email-masked]>

Thanks.

-- 
tejun