Re: [PATCH 1/9] PM / Domains: Allocate memory outside domain locks

[Kevin Hilman <khilman@kernel.org>]

Lina Iyer <lina.iyer@linaro.org> writes:

> In preparation for supporting IRQ-safe domains, allocate domain data
> outside the domain locks. These functions are not called in an atomic
> context, so we can always allocate memory using GFP_KERNEL. By
> allocating memory before the locks, we can safely lock the domain using
> spinlocks instead of mutexes.
>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
> Cc: Kevin Hilman <khilman@linaro.org>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: Krzysztof Kozłowski <k.kozlowski@samsung.com>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>

Reviewed-by: Kevin Hilman <khilman@linaro.org>

> ---
>  drivers/base/power/domain.c | 30 +++++++++++++++---------------
>  1 file changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 7666a1c..5fd1306 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1382,13 +1382,17 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
>  int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
>  			   struct generic_pm_domain *subdomain)
>  {
> -	struct gpd_link *link;
> +	struct gpd_link *link, *itr;
>  	int ret = 0;
>  
>  	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(subdomain)
>  	    || genpd == subdomain)
>  		return -EINVAL;
>  
> +	link = kzalloc(sizeof(*link), GFP_KERNEL);
> +	if (!link)
> +		return -ENOMEM;
> +
>  	mutex_lock(&genpd->lock);
>  	mutex_lock_nested(&subdomain->lock, SINGLE_DEPTH_NESTING);
>  
> @@ -1398,18 +1402,13 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
>  		goto out;
>  	}
>  
> -	list_for_each_entry(link, &genpd->master_links, master_node) {
> -		if (link->slave == subdomain && link->master == genpd) {
> +	list_for_each_entry(itr, &genpd->master_links, master_node) {
> +		if (itr->slave == subdomain && itr->master == genpd) {
>  			ret = -EINVAL;
>  			goto out;
>  		}
>  	}
>  
> -	link = kzalloc(sizeof(*link), GFP_KERNEL);
> -	if (!link) {
> -		ret = -ENOMEM;
> -		goto out;
> -	}
>  	link->master = genpd;
>  	list_add_tail(&link->master_node, &genpd->master_links);
>  	link->slave = subdomain;
> @@ -1420,7 +1419,8 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
>   out:
>  	mutex_unlock(&subdomain->lock);
>  	mutex_unlock(&genpd->lock);
> -
> +	if (ret)
> +		kfree(link);
>  	return ret;
>  }
>  
> @@ -1511,17 +1511,17 @@ int pm_genpd_attach_cpuidle(struct generic_pm_domain *genpd, int state)
>  	if (IS_ERR_OR_NULL(genpd) || state < 0)
>  		return -EINVAL;
>  
> +	cpuidle_data = kzalloc(sizeof(*cpuidle_data), GFP_KERNEL);
> +	if (!cpuidle_data)
> +		return -ENOMEM;
> +
>  	mutex_lock(&genpd->lock);
>  
>  	if (genpd->cpuidle_data) {
>  		ret = -EEXIST;
> -		goto out;
> -	}
> -	cpuidle_data = kzalloc(sizeof(*cpuidle_data), GFP_KERNEL);
> -	if (!cpuidle_data) {
> -		ret = -ENOMEM;
> -		goto out;
> +		goto err_drv;
>  	}
> +
>  	cpuidle_drv = cpuidle_driver_ref();
>  	if (!cpuidle_drv) {
>  		ret = -ENODEV;