2 * net/core/netprio_cgroup.c Priority Control Group
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * Authors: Neil Horman <nhorman@tuxdriver.com>
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/types.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/skbuff.h>
20 #include <linux/cgroup.h>
21 #include <linux/rcupdate.h>
22 #include <linux/atomic.h>
23 #include <net/rtnetlink.h>
24 #include <net/pkt_cls.h>
26 #include <net/netprio_cgroup.h>
28 #include <linux/fdtable.h>
31 * netprio allocates per-net_device priomap array which is indexed by
32 * css->id. Limiting css ID to 16bits doesn't lose anything.
34 #define NETPRIO_ID_MAX USHRT_MAX
36 #define PRIOMAP_MIN_SZ 128
39 * Extend @dev->priomap so that it's large enough to accommodate
40 * @target_idx. @dev->priomap.priomap_len > @target_idx after successful
41 * return. Must be called under rtnl lock.
43 static int extend_netdev_table(struct net_device
*dev
, u32 target_idx
)
45 struct netprio_map
*old
, *new;
46 size_t new_sz
, new_len
;
48 /* is the existing priomap large enough? */
49 old
= rtnl_dereference(dev
->priomap
);
50 if (old
&& old
->priomap_len
> target_idx
)
54 * Determine the new size. Let's keep it power-of-two. We start
55 * from PRIOMAP_MIN_SZ and double it until it's large enough to
56 * accommodate @target_idx.
58 new_sz
= PRIOMAP_MIN_SZ
;
60 new_len
= (new_sz
- offsetof(struct netprio_map
, priomap
)) /
61 sizeof(new->priomap
[0]);
62 if (new_len
> target_idx
)
66 if (WARN_ON(new_sz
< PRIOMAP_MIN_SZ
))
71 new = kzalloc(new_sz
, GFP_KERNEL
);
76 memcpy(new->priomap
, old
->priomap
,
77 old
->priomap_len
* sizeof(old
->priomap
[0]));
79 new->priomap_len
= new_len
;
81 /* install the new priomap */
82 rcu_assign_pointer(dev
->priomap
, new);
89 * netprio_prio - return the effective netprio of a cgroup-net_device pair
90 * @css: css part of the target pair
91 * @dev: net_device part of the target pair
93 * Should be called under RCU read or rtnl lock.
95 static u32
netprio_prio(struct cgroup_subsys_state
*css
, struct net_device
*dev
)
97 struct netprio_map
*map
= rcu_dereference_rtnl(dev
->priomap
);
98 int id
= css
->cgroup
->id
;
100 if (map
&& id
< map
->priomap_len
)
101 return map
->priomap
[id
];
106 * netprio_set_prio - set netprio on a cgroup-net_device pair
107 * @css: css part of the target pair
108 * @dev: net_device part of the target pair
111 * Set netprio to @prio on @css-@dev pair. Should be called under rtnl
112 * lock and may fail under memory pressure for non-zero @prio.
114 static int netprio_set_prio(struct cgroup_subsys_state
*css
,
115 struct net_device
*dev
, u32 prio
)
117 struct netprio_map
*map
;
118 int id
= css
->cgroup
->id
;
121 /* avoid extending priomap for zero writes */
122 map
= rtnl_dereference(dev
->priomap
);
123 if (!prio
&& (!map
|| map
->priomap_len
<= id
))
126 ret
= extend_netdev_table(dev
, id
);
130 map
= rtnl_dereference(dev
->priomap
);
131 map
->priomap
[id
] = prio
;
135 static struct cgroup_subsys_state
*
136 cgrp_css_alloc(struct cgroup_subsys_state
*parent_css
)
138 struct cgroup_subsys_state
*css
;
140 css
= kzalloc(sizeof(*css
), GFP_KERNEL
);
142 return ERR_PTR(-ENOMEM
);
147 static int cgrp_css_online(struct cgroup_subsys_state
*css
)
149 struct cgroup_subsys_state
*parent_css
= css
->parent
;
150 struct net_device
*dev
;
153 if (css
->id
> NETPRIO_ID_MAX
)
161 * Inherit prios from the parent. As all prios are set during
162 * onlining, there is no need to clear them on offline.
164 for_each_netdev(&init_net
, dev
) {
165 u32 prio
= netprio_prio(parent_css
, dev
);
167 ret
= netprio_set_prio(css
, dev
, prio
);
175 static void cgrp_css_free(struct cgroup_subsys_state
*css
)
180 static u64
read_prioidx(struct cgroup_subsys_state
*css
, struct cftype
*cft
)
182 return css
->cgroup
->id
;
185 static int read_priomap(struct seq_file
*sf
, void *v
)
187 struct net_device
*dev
;
190 for_each_netdev_rcu(&init_net
, dev
)
191 seq_printf(sf
, "%s %u\n", dev
->name
,
192 netprio_prio(seq_css(sf
), dev
));
197 static ssize_t
write_priomap(struct kernfs_open_file
*of
,
198 char *buf
, size_t nbytes
, loff_t off
)
200 char devname
[IFNAMSIZ
+ 1];
201 struct net_device
*dev
;
205 if (sscanf(buf
, "%"__stringify(IFNAMSIZ
)"s %u", devname
, &prio
) != 2)
208 dev
= dev_get_by_name(&init_net
, devname
);
212 cgroup_sk_alloc_disable();
216 ret
= netprio_set_prio(of_css(of
), dev
, prio
);
220 return ret
?: nbytes
;
223 static int update_netprio(const void *v
, struct file
*file
, unsigned n
)
226 struct socket
*sock
= sock_from_file(file
, &err
);
228 spin_lock(&cgroup_sk_update_lock
);
229 sock_cgroup_set_prioidx(&sock
->sk
->sk_cgrp_data
,
231 spin_unlock(&cgroup_sk_update_lock
);
236 static void net_prio_attach(struct cgroup_taskset
*tset
)
238 struct task_struct
*p
;
239 struct cgroup_subsys_state
*css
;
241 cgroup_taskset_for_each(p
, css
, tset
) {
242 void *v
= (void *)(unsigned long)css
->cgroup
->id
;
245 iterate_fd(p
->files
, 0, update_netprio
, v
);
250 static struct cftype ss_files
[] = {
253 .read_u64
= read_prioidx
,
257 .seq_show
= read_priomap
,
258 .write
= write_priomap
,
263 struct cgroup_subsys net_prio_cgrp_subsys
= {
264 .css_alloc
= cgrp_css_alloc
,
265 .css_online
= cgrp_css_online
,
266 .css_free
= cgrp_css_free
,
267 .attach
= net_prio_attach
,
268 .legacy_cftypes
= ss_files
,
271 static int netprio_device_event(struct notifier_block
*unused
,
272 unsigned long event
, void *ptr
)
274 struct net_device
*dev
= netdev_notifier_info_to_dev(ptr
);
275 struct netprio_map
*old
;
278 * Note this is called with rtnl_lock held so we have update side
279 * protection on our rcu assignments
283 case NETDEV_UNREGISTER
:
284 old
= rtnl_dereference(dev
->priomap
);
285 RCU_INIT_POINTER(dev
->priomap
, NULL
);
293 static struct notifier_block netprio_device_notifier
= {
294 .notifier_call
= netprio_device_event
297 static int __init
init_cgroup_netprio(void)
299 register_netdevice_notifier(&netprio_device_notifier
);
303 subsys_initcall(init_cgroup_netprio
);
304 MODULE_LICENSE("GPL v2");