| /** | |
| * css_get - obtain a reference on the specified css | |
| * @css: target css | |
| * | |
| * The caller must already have a reference. | |
| */ | |
| CGROUP_REF_FN_ATTRS | |
| void css_get(struct cgroup_subsys_state *css) | |
| { | |
| if (!(css->flags & CSS_NO_REF)) | |
| percpu_ref_get(&css->refcnt); | |
| } | |
| CGROUP_REF_EXPORT(css_get) | |
| /** | |
| * css_get_many - obtain references on the specified css | |
| * @css: target css | |
| * @n: number of references to get | |
| * | |
| * The caller must already have a reference. | |
| */ | |
| CGROUP_REF_FN_ATTRS | |
| void css_get_many(struct cgroup_subsys_state *css, unsigned int n) | |
| { | |
| if (!(css->flags & CSS_NO_REF)) | |
| percpu_ref_get_many(&css->refcnt, n); | |
| } | |
| CGROUP_REF_EXPORT(css_get_many) | |
| /** | |
| * css_tryget - try to obtain a reference on the specified css | |
| * @css: target css | |
| * | |
| * Obtain a reference on @css unless it already has reached zero and is | |
| * being released. This function doesn't care whether @css is on or | |
| * offline. The caller naturally needs to ensure that @css is accessible | |
| * but doesn't have to be holding a reference on it - IOW, RCU protected | |
| * access is good enough for this function. Returns %true if a reference | |
| * count was successfully obtained; %false otherwise. | |
| */ | |
| CGROUP_REF_FN_ATTRS | |
| bool css_tryget(struct cgroup_subsys_state *css) | |
| { | |
| if (!(css->flags & CSS_NO_REF)) | |
| return percpu_ref_tryget(&css->refcnt); | |
| return true; | |
| } | |
| CGROUP_REF_EXPORT(css_tryget) | |
| /** | |
| * css_tryget_online - try to obtain a reference on the specified css if online | |
| * @css: target css | |
| * | |
| * Obtain a reference on @css if it's online. The caller naturally needs | |
| * to ensure that @css is accessible but doesn't have to be holding a | |
| * reference on it - IOW, RCU protected access is good enough for this | |
| * function. Returns %true if a reference count was successfully obtained; | |
| * %false otherwise. | |
| */ | |
| CGROUP_REF_FN_ATTRS | |
| bool css_tryget_online(struct cgroup_subsys_state *css) | |
| { | |
| if (!(css->flags & CSS_NO_REF)) | |
| return percpu_ref_tryget_live(&css->refcnt); | |
| return true; | |
| } | |
| CGROUP_REF_EXPORT(css_tryget_online) | |
| /** | |
| * css_put - put a css reference | |
| * @css: target css | |
| * | |
| * Put a reference obtained via css_get() and css_tryget_online(). | |
| */ | |
| CGROUP_REF_FN_ATTRS | |
| void css_put(struct cgroup_subsys_state *css) | |
| { | |
| if (!(css->flags & CSS_NO_REF)) | |
| percpu_ref_put(&css->refcnt); | |
| } | |
| CGROUP_REF_EXPORT(css_put) | |
| /** | |
| * css_put_many - put css references | |
| * @css: target css | |
| * @n: number of references to put | |
| * | |
| * Put references obtained via css_get() and css_tryget_online(). | |
| */ | |
| CGROUP_REF_FN_ATTRS | |
| void css_put_many(struct cgroup_subsys_state *css, unsigned int n) | |
| { | |
| if (!(css->flags & CSS_NO_REF)) | |
| percpu_ref_put_many(&css->refcnt, n); | |
| } | |
| CGROUP_REF_EXPORT(css_put_many) |