bc2fb7ed08
css_task_iter currently always walks all tasks. With the scheduled cgroup v2 thread support, the iterator would need to handle multiple types of iteration. As a preparation, add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS. If the flag is not specified, it walks all tasks as before. When asserted, the iterator only walks the group leaders. For now, the only user of the flag is cgroup v2 "cgroup.procs" file which no longer needs to skip non-leader tasks in cgroup_procs_next(). Note that cgroup v1 "cgroup.procs" can't use the group leader walk as v1 "cgroup.procs" doesn't mean "list all thread group leaders in the cgroup" but "list all thread group id's with any threads in the cgroup". While at it, update cgroup_procs_show() to use task_pid_vnr() instead of task_tgid_vnr(). As the iteration guarantees that the function only sees group leaders, this doesn't change the output and will allow sharing the function for thread iteration. Signed-off-by: Tejun Heo <tj@kernel.org>
131 lines
3 KiB
C
131 lines
3 KiB
C
/*
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* net/core/netclassid_cgroup.c Classid Cgroupfs Handling
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Thomas Graf <tgraf@suug.ch>
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*/
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#include <linux/slab.h>
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#include <linux/cgroup.h>
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#include <linux/fdtable.h>
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#include <linux/sched/task.h>
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#include <net/cls_cgroup.h>
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#include <net/sock.h>
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static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
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{
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return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
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}
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struct cgroup_cls_state *task_cls_state(struct task_struct *p)
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{
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return css_cls_state(task_css_check(p, net_cls_cgrp_id,
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rcu_read_lock_bh_held()));
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}
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EXPORT_SYMBOL_GPL(task_cls_state);
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static struct cgroup_subsys_state *
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cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
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{
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struct cgroup_cls_state *cs;
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cs = kzalloc(sizeof(*cs), GFP_KERNEL);
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if (!cs)
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return ERR_PTR(-ENOMEM);
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return &cs->css;
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}
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static int cgrp_css_online(struct cgroup_subsys_state *css)
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{
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struct cgroup_cls_state *cs = css_cls_state(css);
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struct cgroup_cls_state *parent = css_cls_state(css->parent);
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if (parent)
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cs->classid = parent->classid;
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return 0;
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}
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static void cgrp_css_free(struct cgroup_subsys_state *css)
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{
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kfree(css_cls_state(css));
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}
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static int update_classid_sock(const void *v, struct file *file, unsigned n)
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{
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int err;
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struct socket *sock = sock_from_file(file, &err);
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if (sock) {
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spin_lock(&cgroup_sk_update_lock);
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sock_cgroup_set_classid(&sock->sk->sk_cgrp_data,
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(unsigned long)v);
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spin_unlock(&cgroup_sk_update_lock);
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}
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return 0;
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}
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static void cgrp_attach(struct cgroup_taskset *tset)
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{
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struct cgroup_subsys_state *css;
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struct task_struct *p;
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cgroup_taskset_for_each(p, css, tset) {
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task_lock(p);
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iterate_fd(p->files, 0, update_classid_sock,
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(void *)(unsigned long)css_cls_state(css)->classid);
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task_unlock(p);
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}
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}
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static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
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{
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return css_cls_state(css)->classid;
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}
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static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
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u64 value)
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{
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struct cgroup_cls_state *cs = css_cls_state(css);
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struct css_task_iter it;
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struct task_struct *p;
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cgroup_sk_alloc_disable();
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cs->classid = (u32)value;
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css_task_iter_start(css, 0, &it);
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while ((p = css_task_iter_next(&it))) {
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task_lock(p);
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iterate_fd(p->files, 0, update_classid_sock,
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(void *)(unsigned long)cs->classid);
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task_unlock(p);
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}
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css_task_iter_end(&it);
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return 0;
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}
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static struct cftype ss_files[] = {
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{
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.name = "classid",
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.read_u64 = read_classid,
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.write_u64 = write_classid,
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},
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{ } /* terminate */
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};
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struct cgroup_subsys net_cls_cgrp_subsys = {
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.css_alloc = cgrp_css_alloc,
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.css_online = cgrp_css_online,
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.css_free = cgrp_css_free,
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.attach = cgrp_attach,
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.legacy_cftypes = ss_files,
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};
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