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author | Tejun Heo <tj@kernel.org> | 2013-06-24 15:21:48 -0700 |
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committer | Tejun Heo <tj@kernel.org> | 2013-06-24 15:21:48 -0700 |
commit | b326f9d0dbd066b0aafbe88e6011a680a36de6e8 (patch) | |
tree | 4e2234cea36ac5ff5e7c8243100e421c2d9e4a8c /kernel | |
parent | a8a648c4acee2095262f7fa65b0d8a68a03c32e4 (diff) | |
download | linux-b326f9d0dbd066b0aafbe88e6011a680a36de6e8.tar.bz2 |
cgroup: clean up find_css_set() and friends
find_css_set() passes uninitialized on-stack template[] array to
find_existing_css_set() which sets the entries for all subsystems.
Passing around an uninitialized array is a bit icky and we want to
introduce an iterator which only iterates loaded subsystems. Let's
initialize it on definition.
While at it, also make the following cosmetic cleanups.
* Convert to proper /** comments.
* Reorder variable declarations.
* Replace comment on synchronization with lockdep_assert_held().
This patch doesn't make any functional differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/cgroup.c | 38 |
1 files changed, 17 insertions, 21 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 67fc953c816a..c8d3175c429c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -434,7 +434,7 @@ static inline void put_css_set_taskexit(struct css_set *cset) __put_css_set(cset, 1); } -/* +/** * compare_css_sets - helper function for find_existing_css_set(). * @cset: candidate css_set being tested * @old_cset: existing css_set for a task @@ -506,27 +506,20 @@ static bool compare_css_sets(struct css_set *cset, return true; } -/* - * find_existing_css_set() is a helper for - * find_css_set(), and checks to see whether an existing - * css_set is suitable. - * - * oldcg: the cgroup group that we're using before the cgroup - * transition - * - * cgrp: the cgroup that we're moving into - * - * template: location in which to build the desired set of subsystem - * state objects for the new cgroup group +/** + * find_existing_css_set - init css array and find the matching css_set + * @old_cset: the css_set that we're using before the cgroup transition + * @cgrp: the cgroup that we're moving into + * @template: out param for the new set of csses, should be clear on entry */ static struct css_set *find_existing_css_set(struct css_set *old_cset, struct cgroup *cgrp, struct cgroup_subsys_state *template[]) { - int i; struct cgroupfs_root *root = cgrp->root; struct css_set *cset; unsigned long key; + int i; /* * Build the set of subsystem state objects that we want to see in the @@ -618,22 +611,25 @@ static void link_css_set(struct list_head *tmp_links, struct css_set *cset, list_add_tail(&link->cgrp_link, &cset->cgrp_links); } -/* - * find_css_set() takes an existing cgroup group and a - * cgroup object, and returns a css_set object that's - * equivalent to the old group, but with the given cgroup - * substituted into the appropriate hierarchy. Must be called with - * cgroup_mutex held +/** + * find_css_set - return a new css_set with one cgroup updated + * @old_cset: the baseline css_set + * @cgrp: the cgroup to be updated + * + * Return a new css_set that's equivalent to @old_cset, but with @cgrp + * substituted into the appropriate hierarchy. */ static struct css_set *find_css_set(struct css_set *old_cset, struct cgroup *cgrp) { + struct cgroup_subsys_state *template[CGROUP_SUBSYS_COUNT] = { }; struct css_set *cset; - struct cgroup_subsys_state *template[CGROUP_SUBSYS_COUNT]; struct list_head tmp_links; struct cgrp_cset_link *link; unsigned long key; + lockdep_assert_held(&cgroup_mutex); + /* First see if we already have a cgroup group that matches * the desired set */ read_lock(&css_set_lock); |