cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated codes

[PATCH] cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated codes

Posted by Lin Feng 3 years, 10 months ago

No funtionality change, but save us some lines.

Signed-off-by: Lin Feng <linf@wangsu.com>
---
 kernel/cgroup/cgroup.c | 58 ++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 31 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 1779ccddb734..a8a46eb66f21 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1376,6 +1376,31 @@ static void cgroup_destroy_root(struct cgroup_root *root)
 	cgroup_free_root(root);
 }
 
+static inline struct cgroup *__cset_cgroup_from_root(struct css_set *cset,
+					    struct cgroup_root *root)
+{
+	struct cgroup *res_cgroup = NULL;
+
+	if (cset == &init_css_set) {
+		res_cgroup = &root->cgrp;
+	} else if (root == &cgrp_dfl_root) {
+		res_cgroup = cset->dfl_cgrp;
+	} else {
+		struct cgrp_cset_link *link;
+
+		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
+			struct cgroup *c = link->cgrp;
+
+			if (c->root == root) {
+				res_cgroup = c;
+				break;
+			}
+		}
+	}
+
+	return res_cgroup;
+}
+
 /*
  * look up cgroup associated with current task's cgroup namespace on the
  * specified hierarchy
@@ -1391,22 +1416,8 @@ current_cgns_cgroup_from_root(struct cgroup_root *root)
 	rcu_read_lock();
 
 	cset = current->nsproxy->cgroup_ns->root_cset;
-	if (cset == &init_css_set) {
-		res = &root->cgrp;
-	} else if (root == &cgrp_dfl_root) {
-		res = cset->dfl_cgrp;
-	} else {
-		struct cgrp_cset_link *link;
-
-		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
-			struct cgroup *c = link->cgrp;
+	res = __cset_cgroup_from_root(cset, root);
 
-			if (c->root == root) {
-				res = c;
-				break;
-			}
-		}
-	}
 	rcu_read_unlock();
 
 	BUG_ON(!res);
@@ -1422,22 +1433,7 @@ static struct cgroup *cset_cgroup_from_root(struct css_set *cset,
 	lockdep_assert_held(&cgroup_mutex);
 	lockdep_assert_held(&css_set_lock);
 
-	if (cset == &init_css_set) {
-		res = &root->cgrp;
-	} else if (root == &cgrp_dfl_root) {
-		res = cset->dfl_cgrp;
-	} else {
-		struct cgrp_cset_link *link;
-
-		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
-			struct cgroup *c = link->cgrp;
-
-			if (c->root == root) {
-				res = c;
-				break;
-			}
-		}
-	}
+	res = __cset_cgroup_from_root(cset, root);
 
 	BUG_ON(!res);
 	return res;
-- 
2.31.1

Re: [PATCH] cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated codes

Posted by Tejun Heo 3 years, 10 months ago

On Thu, Jun 16, 2022 at 06:38:30PM +0800, Lin Feng wrote:
> No funtionality change, but save us some lines.
> 
> Signed-off-by: Lin Feng <linf@wangsu.com>

Applied to cgroup/for-5.20.

Thanks.

-- 
tejun

Re: [PATCH] cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated codes

Posted by Mukesh Ojha 3 years, 10 months ago

Hi,

On 6/16/2022 4:08 PM, Lin Feng wrote:
> No funtionality change, but save us some lines.
> 
> Signed-off-by: Lin Feng <linf@wangsu.com>
> ---
>   kernel/cgroup/cgroup.c | 58 ++++++++++++++++++++----------------------
>   1 file changed, 27 insertions(+), 31 deletions(-)
> 
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index 1779ccddb734..a8a46eb66f21 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -1376,6 +1376,31 @@ static void cgroup_destroy_root(struct cgroup_root *root)
>   	cgroup_free_root(root);
>   }
>   
> +static inline struct cgroup *__cset_cgroup_from_root(struct css_set *cset,
> +					    struct cgroup_root *root)
> +{
> +	struct cgroup *res_cgroup = NULL;
> +
> +	if (cset == &init_css_set) {
> +		res_cgroup = &root->cgrp;
> +	} else if (root == &cgrp_dfl_root) {
> +		res_cgroup = cset->dfl_cgrp;
> +	} else {
> +		struct cgrp_cset_link *link;
> +
> +		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
> +			struct cgroup *c = link->cgrp;
> +
> +			if (c->root == root) {
> +				res_cgroup = c;
> +				break;
> +			}
> +		}
> +	}
> +
> +	return res_cgroup;
> +}
> +
>   /*
>    * look up cgroup associated with current task's cgroup namespace on the
>    * specified hierarchy
> @@ -1391,22 +1416,8 @@ current_cgns_cgroup_from_root(struct cgroup_root *root)
>   	rcu_read_lock();
>   
>   	cset = current->nsproxy->cgroup_ns->root_cset;
> -	if (cset == &init_css_set) {
> -		res = &root->cgrp;
> -	} else if (root == &cgrp_dfl_root) {
> -		res = cset->dfl_cgrp;
> -	} else {
> -		struct cgrp_cset_link *link;
> -
> -		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
> -			struct cgroup *c = link->cgrp;
> +	res = __cset_cgroup_from_root(cset, root);
>   
> -			if (c->root == root) {
> -				res = c;
> -				break;
> -			}
> -		}
> -	}
>   	rcu_read_unlock();
>   
>   	BUG_ON(!res);
> @@ -1422,22 +1433,7 @@ static struct cgroup *cset_cgroup_from_root(struct css_set *cset,
>   	lockdep_assert_held(&cgroup_mutex);
>   	lockdep_assert_held(&css_set_lock);
>   
> -	if (cset == &init_css_set) {
> -		res = &root->cgrp;
> -	} else if (root == &cgrp_dfl_root) {
> -		res = cset->dfl_cgrp;
> -	} else {
> -		struct cgrp_cset_link *link;
> -
> -		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
> -			struct cgroup *c = link->cgrp;
> -
> -			if (c->root == root) {
> -				res = c;
> -				break;
> -			}
> -		}
> -	}
> +	res = __cset_cgroup_from_root(cset, root);
>   
>   	BUG_ON(!res);
>   	return res;


Thanks for the patch
Liked the idea.

Acked-by: Mukesh Ojha <quic_mojha@quicinc.com>

-Mukesh