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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 13:55:32 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
Pull cgroup hierarchy update from Tejun Heo: "Currently, different cgroup subsystems handle nested cgroups completely differently. There's no consistency among subsystems and the behaviors often are outright broken. People at least seem to agree that the broken hierarhcy behaviors need to be weeded out if any progress is gonna be made on this front and that the fallouts from deprecating the broken behaviors should be acceptable especially given that the current behaviors don't make much sense when nested. This patch makes cgroup emit warning messages if cgroups for subsystems with broken hierarchy behavior are nested to prepare for fixing them in the future. This was put in a separate branch because more related changes were expected (didn't make it this round) and the memory cgroup wanted to pull in this and make changes on top." * 'for-3.7-hierarchy' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them
405 lines
8.7 KiB
C
405 lines
8.7 KiB
C
/*
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* net/core/netprio_cgroup.c Priority Control Group
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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: Neil Horman <nhorman@tuxdriver.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/skbuff.h>
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#include <linux/cgroup.h>
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#include <linux/rcupdate.h>
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#include <linux/atomic.h>
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#include <net/rtnetlink.h>
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#include <net/pkt_cls.h>
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#include <net/sock.h>
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#include <net/netprio_cgroup.h>
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#include <linux/fdtable.h>
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#define PRIOIDX_SZ 128
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static unsigned long prioidx_map[PRIOIDX_SZ];
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static DEFINE_SPINLOCK(prioidx_map_lock);
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static atomic_t max_prioidx = ATOMIC_INIT(0);
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static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
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{
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return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
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struct cgroup_netprio_state, css);
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}
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static int get_prioidx(u32 *prio)
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{
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unsigned long flags;
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u32 prioidx;
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spin_lock_irqsave(&prioidx_map_lock, flags);
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prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ);
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if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) {
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spin_unlock_irqrestore(&prioidx_map_lock, flags);
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return -ENOSPC;
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}
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set_bit(prioidx, prioidx_map);
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if (atomic_read(&max_prioidx) < prioidx)
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atomic_set(&max_prioidx, prioidx);
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spin_unlock_irqrestore(&prioidx_map_lock, flags);
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*prio = prioidx;
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return 0;
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}
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static void put_prioidx(u32 idx)
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{
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unsigned long flags;
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spin_lock_irqsave(&prioidx_map_lock, flags);
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clear_bit(idx, prioidx_map);
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spin_unlock_irqrestore(&prioidx_map_lock, flags);
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}
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static int extend_netdev_table(struct net_device *dev, u32 new_len)
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{
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size_t new_size = sizeof(struct netprio_map) +
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((sizeof(u32) * new_len));
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struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
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struct netprio_map *old_priomap;
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int i;
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old_priomap = rtnl_dereference(dev->priomap);
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if (!new_priomap) {
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pr_warn("Unable to alloc new priomap!\n");
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return -ENOMEM;
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}
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for (i = 0;
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old_priomap && (i < old_priomap->priomap_len);
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i++)
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new_priomap->priomap[i] = old_priomap->priomap[i];
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new_priomap->priomap_len = new_len;
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rcu_assign_pointer(dev->priomap, new_priomap);
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if (old_priomap)
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kfree_rcu(old_priomap, rcu);
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return 0;
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}
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static int write_update_netdev_table(struct net_device *dev)
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{
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int ret = 0;
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u32 max_len;
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struct netprio_map *map;
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max_len = atomic_read(&max_prioidx) + 1;
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map = rtnl_dereference(dev->priomap);
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if (!map || map->priomap_len < max_len)
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ret = extend_netdev_table(dev, max_len);
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return ret;
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}
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static int update_netdev_tables(void)
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{
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int ret = 0;
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struct net_device *dev;
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u32 max_len;
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struct netprio_map *map;
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rtnl_lock();
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max_len = atomic_read(&max_prioidx) + 1;
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for_each_netdev(&init_net, dev) {
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map = rtnl_dereference(dev->priomap);
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/*
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* don't allocate priomap if we didn't
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* change net_prio.ifpriomap (map == NULL),
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* this will speed up skb_update_prio.
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*/
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if (map && map->priomap_len < max_len) {
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ret = extend_netdev_table(dev, max_len);
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if (ret < 0)
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break;
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}
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}
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rtnl_unlock();
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return ret;
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}
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static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
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{
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struct cgroup_netprio_state *cs;
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int ret = -EINVAL;
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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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if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx)
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goto out;
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ret = get_prioidx(&cs->prioidx);
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if (ret < 0) {
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pr_warn("No space in priority index array\n");
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goto out;
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}
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ret = update_netdev_tables();
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if (ret < 0) {
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put_prioidx(cs->prioidx);
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goto out;
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}
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return &cs->css;
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out:
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kfree(cs);
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return ERR_PTR(ret);
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}
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static void cgrp_destroy(struct cgroup *cgrp)
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{
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struct cgroup_netprio_state *cs;
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struct net_device *dev;
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struct netprio_map *map;
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cs = cgrp_netprio_state(cgrp);
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rtnl_lock();
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for_each_netdev(&init_net, dev) {
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map = rtnl_dereference(dev->priomap);
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if (map && cs->prioidx < map->priomap_len)
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map->priomap[cs->prioidx] = 0;
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}
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rtnl_unlock();
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put_prioidx(cs->prioidx);
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kfree(cs);
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}
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static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
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{
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return (u64)cgrp_netprio_state(cgrp)->prioidx;
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}
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static int read_priomap(struct cgroup *cont, struct cftype *cft,
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struct cgroup_map_cb *cb)
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{
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struct net_device *dev;
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u32 prioidx = cgrp_netprio_state(cont)->prioidx;
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u32 priority;
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struct netprio_map *map;
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rcu_read_lock();
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for_each_netdev_rcu(&init_net, dev) {
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map = rcu_dereference(dev->priomap);
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priority = (map && prioidx < map->priomap_len) ? map->priomap[prioidx] : 0;
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cb->fill(cb, dev->name, priority);
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}
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rcu_read_unlock();
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return 0;
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}
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static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
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const char *buffer)
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{
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char *devname = kstrdup(buffer, GFP_KERNEL);
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int ret = -EINVAL;
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u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
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unsigned long priority;
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char *priostr;
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struct net_device *dev;
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struct netprio_map *map;
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if (!devname)
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return -ENOMEM;
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/*
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* Minimally sized valid priomap string
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*/
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if (strlen(devname) < 3)
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goto out_free_devname;
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priostr = strstr(devname, " ");
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if (!priostr)
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goto out_free_devname;
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/*
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*Separate the devname from the associated priority
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*and advance the priostr pointer to the priority value
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*/
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*priostr = '\0';
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priostr++;
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/*
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* If the priostr points to NULL, we're at the end of the passed
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* in string, and its not a valid write
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*/
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if (*priostr == '\0')
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goto out_free_devname;
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ret = kstrtoul(priostr, 10, &priority);
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if (ret < 0)
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goto out_free_devname;
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ret = -ENODEV;
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dev = dev_get_by_name(&init_net, devname);
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if (!dev)
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goto out_free_devname;
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rtnl_lock();
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ret = write_update_netdev_table(dev);
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if (ret < 0)
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goto out_put_dev;
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map = rtnl_dereference(dev->priomap);
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if (map)
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map->priomap[prioidx] = priority;
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out_put_dev:
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rtnl_unlock();
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dev_put(dev);
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out_free_devname:
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kfree(devname);
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return ret;
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}
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void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
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{
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struct task_struct *p;
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cgroup_taskset_for_each(p, cgrp, tset) {
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unsigned int fd;
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struct fdtable *fdt;
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struct files_struct *files;
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task_lock(p);
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files = p->files;
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if (!files) {
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task_unlock(p);
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continue;
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}
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spin_lock(&files->file_lock);
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fdt = files_fdtable(files);
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for (fd = 0; fd < fdt->max_fds; fd++) {
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struct file *file;
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struct socket *sock;
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int err;
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file = fcheck_files(files, fd);
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if (!file)
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continue;
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sock = sock_from_file(file, &err);
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if (sock)
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sock_update_netprioidx(sock->sk, p);
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}
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spin_unlock(&files->file_lock);
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task_unlock(p);
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}
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}
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static struct cftype ss_files[] = {
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{
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.name = "prioidx",
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.read_u64 = read_prioidx,
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},
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{
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.name = "ifpriomap",
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.read_map = read_priomap,
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.write_string = write_priomap,
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},
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{ } /* terminate */
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};
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struct cgroup_subsys net_prio_subsys = {
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.name = "net_prio",
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.create = cgrp_create,
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.destroy = cgrp_destroy,
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.attach = net_prio_attach,
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.subsys_id = net_prio_subsys_id,
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.base_cftypes = ss_files,
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.module = THIS_MODULE,
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/*
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* net_prio has artificial limit on the number of cgroups and
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* disallows nesting making it impossible to co-mount it with other
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* hierarchical subsystems. Remove the artificially low PRIOIDX_SZ
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* limit and properly nest configuration such that children follow
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* their parents' configurations by default and are allowed to
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* override and remove the following.
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*/
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.broken_hierarchy = true,
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};
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static int netprio_device_event(struct notifier_block *unused,
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unsigned long event, void *ptr)
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{
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struct net_device *dev = ptr;
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struct netprio_map *old;
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/*
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* Note this is called with rtnl_lock held so we have update side
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* protection on our rcu assignments
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*/
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switch (event) {
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case NETDEV_UNREGISTER:
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old = rtnl_dereference(dev->priomap);
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RCU_INIT_POINTER(dev->priomap, NULL);
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if (old)
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kfree_rcu(old, rcu);
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break;
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}
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return NOTIFY_DONE;
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}
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static struct notifier_block netprio_device_notifier = {
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.notifier_call = netprio_device_event
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};
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static int __init init_cgroup_netprio(void)
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{
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int ret;
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ret = cgroup_load_subsys(&net_prio_subsys);
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if (ret)
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goto out;
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register_netdevice_notifier(&netprio_device_notifier);
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out:
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return ret;
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}
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static void __exit exit_cgroup_netprio(void)
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{
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struct netprio_map *old;
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struct net_device *dev;
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unregister_netdevice_notifier(&netprio_device_notifier);
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cgroup_unload_subsys(&net_prio_subsys);
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rtnl_lock();
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for_each_netdev(&init_net, dev) {
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old = rtnl_dereference(dev->priomap);
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RCU_INIT_POINTER(dev->priomap, NULL);
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if (old)
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kfree_rcu(old, rcu);
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}
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rtnl_unlock();
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}
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module_init(init_cgroup_netprio);
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module_exit(exit_cgroup_netprio);
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MODULE_LICENSE("GPL v2");
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