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Diffstat (limited to 'net/core/netprio_cgroup.c')
-rw-r--r--net/core/netprio_cgroup.c260
1 files changed, 113 insertions, 147 deletions
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index 79285a36035f..bde53da9cd86 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -27,11 +27,7 @@
#include <linux/fdtable.h>
-#define PRIOIDX_SZ 128
-
-static unsigned long prioidx_map[PRIOIDX_SZ];
-static DEFINE_SPINLOCK(prioidx_map_lock);
-static atomic_t max_prioidx = ATOMIC_INIT(0);
+#define PRIOMAP_MIN_SZ 128
static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
{
@@ -39,136 +35,157 @@ static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgr
struct cgroup_netprio_state, css);
}
-static int get_prioidx(u32 *prio)
-{
- unsigned long flags;
- u32 prioidx;
-
- spin_lock_irqsave(&prioidx_map_lock, flags);
- prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ);
- if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) {
- spin_unlock_irqrestore(&prioidx_map_lock, flags);
- return -ENOSPC;
- }
- set_bit(prioidx, prioidx_map);
- if (atomic_read(&max_prioidx) < prioidx)
- atomic_set(&max_prioidx, prioidx);
- spin_unlock_irqrestore(&prioidx_map_lock, flags);
- *prio = prioidx;
- return 0;
-}
-
-static void put_prioidx(u32 idx)
+/*
+ * Extend @dev->priomap so that it's large enough to accomodate
+ * @target_idx. @dev->priomap.priomap_len > @target_idx after successful
+ * return. Must be called under rtnl lock.
+ */
+static int extend_netdev_table(struct net_device *dev, u32 target_idx)
{
- unsigned long flags;
-
- spin_lock_irqsave(&prioidx_map_lock, flags);
- clear_bit(idx, prioidx_map);
- spin_unlock_irqrestore(&prioidx_map_lock, flags);
-}
+ struct netprio_map *old, *new;
+ size_t new_sz, new_len;
-static int extend_netdev_table(struct net_device *dev, u32 new_len)
-{
- size_t new_size = sizeof(struct netprio_map) +
- ((sizeof(u32) * new_len));
- struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
- struct netprio_map *old_priomap;
+ /* is the existing priomap large enough? */
+ old = rtnl_dereference(dev->priomap);
+ if (old && old->priomap_len > target_idx)
+ return 0;
- old_priomap = rtnl_dereference(dev->priomap);
+ /*
+ * Determine the new size. Let's keep it power-of-two. We start
+ * from PRIOMAP_MIN_SZ and double it until it's large enough to
+ * accommodate @target_idx.
+ */
+ new_sz = PRIOMAP_MIN_SZ;
+ while (true) {
+ new_len = (new_sz - offsetof(struct netprio_map, priomap)) /
+ sizeof(new->priomap[0]);
+ if (new_len > target_idx)
+ break;
+ new_sz *= 2;
+ /* overflowed? */
+ if (WARN_ON(new_sz < PRIOMAP_MIN_SZ))
+ return -ENOSPC;
+ }
- if (!new_priomap) {
+ /* allocate & copy */
+ new = kzalloc(new_sz, GFP_KERNEL);
+ if (!new) {
pr_warn("Unable to alloc new priomap!\n");
return -ENOMEM;
}
- if (old_priomap)
- memcpy(new_priomap->priomap, old_priomap->priomap,
- old_priomap->priomap_len *
- sizeof(old_priomap->priomap[0]));
+ if (old)
+ memcpy(new->priomap, old->priomap,
+ old->priomap_len * sizeof(old->priomap[0]));
- new_priomap->priomap_len = new_len;
+ new->priomap_len = new_len;
- rcu_assign_pointer(dev->priomap, new_priomap);
- if (old_priomap)
- kfree_rcu(old_priomap, rcu);
+ /* install the new priomap */
+ rcu_assign_pointer(dev->priomap, new);
+ if (old)
+ kfree_rcu(old, rcu);
return 0;
}
-static int write_update_netdev_table(struct net_device *dev)
+/**
+ * netprio_prio - return the effective netprio of a cgroup-net_device pair
+ * @cgrp: cgroup part of the target pair
+ * @dev: net_device part of the target pair
+ *
+ * Should be called under RCU read or rtnl lock.
+ */
+static u32 netprio_prio(struct cgroup *cgrp, struct net_device *dev)
+{
+ struct netprio_map *map = rcu_dereference_rtnl(dev->priomap);
+
+ if (map && cgrp->id < map->priomap_len)
+ return map->priomap[cgrp->id];
+ return 0;
+}
+
+/**
+ * netprio_set_prio - set netprio on a cgroup-net_device pair
+ * @cgrp: cgroup part of the target pair
+ * @dev: net_device part of the target pair
+ * @prio: prio to set
+ *
+ * Set netprio to @prio on @cgrp-@dev pair. Should be called under rtnl
+ * lock and may fail under memory pressure for non-zero @prio.
+ */
+static int netprio_set_prio(struct cgroup *cgrp, struct net_device *dev,
+ u32 prio)
{
- int ret = 0;
- u32 max_len;
struct netprio_map *map;
+ int ret;
- max_len = atomic_read(&max_prioidx) + 1;
+ /* avoid extending priomap for zero writes */
map = rtnl_dereference(dev->priomap);
- if (!map || map->priomap_len < max_len)
- ret = extend_netdev_table(dev, max_len);
+ if (!prio && (!map || map->priomap_len <= cgrp->id))
+ return 0;
- return ret;
+ ret = extend_netdev_table(dev, cgrp->id);
+ if (ret)
+ return ret;
+
+ map = rtnl_dereference(dev->priomap);
+ map->priomap[cgrp->id] = prio;
+ return 0;
}
-static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
+static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)
{
struct cgroup_netprio_state *cs;
- int ret = -EINVAL;
cs = kzalloc(sizeof(*cs), GFP_KERNEL);
if (!cs)
return ERR_PTR(-ENOMEM);
- if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx)
- goto out;
-
- ret = get_prioidx(&cs->prioidx);
- if (ret < 0) {
- pr_warn("No space in priority index array\n");
- goto out;
- }
-
return &cs->css;
-out:
- kfree(cs);
- return ERR_PTR(ret);
}
-static void cgrp_destroy(struct cgroup *cgrp)
+static int cgrp_css_online(struct cgroup *cgrp)
{
- struct cgroup_netprio_state *cs;
+ struct cgroup *parent = cgrp->parent;
struct net_device *dev;
- struct netprio_map *map;
+ int ret = 0;
+
+ if (!parent)
+ return 0;
- cs = cgrp_netprio_state(cgrp);
rtnl_lock();
+ /*
+ * Inherit prios from the parent. As all prios are set during
+ * onlining, there is no need to clear them on offline.
+ */
for_each_netdev(&init_net, dev) {
- map = rtnl_dereference(dev->priomap);
- if (map && cs->prioidx < map->priomap_len)
- map->priomap[cs->prioidx] = 0;
+ u32 prio = netprio_prio(parent, dev);
+
+ ret = netprio_set_prio(cgrp, dev, prio);
+ if (ret)
+ break;
}
rtnl_unlock();
- put_prioidx(cs->prioidx);
- kfree(cs);
+ return ret;
+}
+
+static void cgrp_css_free(struct cgroup *cgrp)
+{
+ kfree(cgrp_netprio_state(cgrp));
}
static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
{
- return (u64)cgrp_netprio_state(cgrp)->prioidx;
+ return cgrp->id;
}
static int read_priomap(struct cgroup *cont, struct cftype *cft,
struct cgroup_map_cb *cb)
{
struct net_device *dev;
- u32 prioidx = cgrp_netprio_state(cont)->prioidx;
- u32 priority;
- struct netprio_map *map;
rcu_read_lock();
- for_each_netdev_rcu(&init_net, dev) {
- map = rcu_dereference(dev->priomap);
- priority = (map && prioidx < map->priomap_len) ? map->priomap[prioidx] : 0;
- cb->fill(cb, dev->name, priority);
- }
+ for_each_netdev_rcu(&init_net, dev)
+ cb->fill(cb, dev->name, netprio_prio(cont, dev));
rcu_read_unlock();
return 0;
}
@@ -176,66 +193,24 @@ static int read_priomap(struct cgroup *cont, struct cftype *cft,
static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
const char *buffer)
{
- char *devname = kstrdup(buffer, GFP_KERNEL);
- int ret = -EINVAL;
- u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
- unsigned long priority;
- char *priostr;
+ char devname[IFNAMSIZ + 1];
struct net_device *dev;
- struct netprio_map *map;
-
- if (!devname)
- return -ENOMEM;
-
- /*
- * Minimally sized valid priomap string
- */
- if (strlen(devname) < 3)
- goto out_free_devname;
-
- priostr = strstr(devname, " ");
- if (!priostr)
- goto out_free_devname;
-
- /*
- *Separate the devname from the associated priority
- *and advance the priostr pointer to the priority value
- */
- *priostr = '\0';
- priostr++;
-
- /*
- * If the priostr points to NULL, we're at the end of the passed
- * in string, and its not a valid write
- */
- if (*priostr == '\0')
- goto out_free_devname;
-
- ret = kstrtoul(priostr, 10, &priority);
- if (ret < 0)
- goto out_free_devname;
+ u32 prio;
+ int ret;
- ret = -ENODEV;
+ if (sscanf(buffer, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2)
+ return -EINVAL;
dev = dev_get_by_name(&init_net, devname);
if (!dev)
- goto out_free_devname;
+ return -ENODEV;
rtnl_lock();
- ret = write_update_netdev_table(dev);
- if (ret < 0)
- goto out_put_dev;
- map = rtnl_dereference(dev->priomap);
- if (map)
- map->priomap[prioidx] = priority;
+ ret = netprio_set_prio(cgrp, dev, prio);
-out_put_dev:
rtnl_unlock();
dev_put(dev);
-
-out_free_devname:
- kfree(devname);
return ret;
}
@@ -276,22 +251,13 @@ static struct cftype ss_files[] = {
struct cgroup_subsys net_prio_subsys = {
.name = "net_prio",
- .create = cgrp_create,
- .destroy = cgrp_destroy,
+ .css_alloc = cgrp_css_alloc,
+ .css_online = cgrp_css_online,
+ .css_free = cgrp_css_free,
.attach = net_prio_attach,
.subsys_id = net_prio_subsys_id,
.base_cftypes = ss_files,
.module = THIS_MODULE,
-
- /*
- * net_prio has artificial limit on the number of cgroups and
- * disallows nesting making it impossible to co-mount it with other
- * hierarchical subsystems. Remove the artificially low PRIOIDX_SZ
- * limit and properly nest configuration such that children follow
- * their parents' configurations by default and are allowed to
- * override and remove the following.
- */
- .broken_hierarchy = true,
};
static int netprio_device_event(struct notifier_block *unused,

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