linux/net/core/flow.c
Linus Torvalds 467a9e1633 CPU hotplug notifiers registration fixes for 3.15-rc1
The purpose of this single series of commits from Srivatsa S Bhat (with
 a small piece from Gautham R Shenoy) touching multiple subsystems that use
 CPU hotplug notifiers is to provide a way to register them that will not
 lead to deadlocks with CPU online/offline operations as described in the
 changelog of commit 93ae4f978c (CPU hotplug: Provide lockless versions
 of callback registration functions).
 
 The first three commits in the series introduce the API and document it
 and the rest simply goes through the users of CPU hotplug notifiers and
 converts them to using the new method.
 
 /
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Merge tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull CPU hotplug notifiers registration fixes from Rafael Wysocki:
 "The purpose of this single series of commits from Srivatsa S Bhat
  (with a small piece from Gautham R Shenoy) touching multiple
  subsystems that use CPU hotplug notifiers is to provide a way to
  register them that will not lead to deadlocks with CPU online/offline
  operations as described in the changelog of commit 93ae4f978c ("CPU
  hotplug: Provide lockless versions of callback registration
  functions").

  The first three commits in the series introduce the API and document
  it and the rest simply goes through the users of CPU hotplug notifiers
  and converts them to using the new method"

* tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits)
  net/iucv/iucv.c: Fix CPU hotplug callback registration
  net/core/flow.c: Fix CPU hotplug callback registration
  mm, zswap: Fix CPU hotplug callback registration
  mm, vmstat: Fix CPU hotplug callback registration
  profile: Fix CPU hotplug callback registration
  trace, ring-buffer: Fix CPU hotplug callback registration
  xen, balloon: Fix CPU hotplug callback registration
  hwmon, via-cputemp: Fix CPU hotplug callback registration
  hwmon, coretemp: Fix CPU hotplug callback registration
  thermal, x86-pkg-temp: Fix CPU hotplug callback registration
  octeon, watchdog: Fix CPU hotplug callback registration
  oprofile, nmi-timer: Fix CPU hotplug callback registration
  intel-idle: Fix CPU hotplug callback registration
  clocksource, dummy-timer: Fix CPU hotplug callback registration
  drivers/base/topology.c: Fix CPU hotplug callback registration
  acpi-cpufreq: Fix CPU hotplug callback registration
  zsmalloc: Fix CPU hotplug callback registration
  scsi, fcoe: Fix CPU hotplug callback registration
  scsi, bnx2fc: Fix CPU hotplug callback registration
  scsi, bnx2i: Fix CPU hotplug callback registration
  ...
2014-04-07 14:55:46 -07:00

512 lines
12 KiB
C

/* flow.c: Generic flow cache.
*
* Copyright (C) 2003 Alexey N. Kuznetsov (kuznet@ms2.inr.ac.ru)
* Copyright (C) 2003 David S. Miller (davem@redhat.com)
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/jhash.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <linux/percpu.h>
#include <linux/bitops.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/mutex.h>
#include <net/flow.h>
#include <linux/atomic.h>
#include <linux/security.h>
#include <net/net_namespace.h>
struct flow_cache_entry {
union {
struct hlist_node hlist;
struct list_head gc_list;
} u;
struct net *net;
u16 family;
u8 dir;
u32 genid;
struct flowi key;
struct flow_cache_object *object;
};
struct flow_flush_info {
struct flow_cache *cache;
atomic_t cpuleft;
struct completion completion;
};
static struct kmem_cache *flow_cachep __read_mostly;
#define flow_cache_hash_size(cache) (1 << (cache)->hash_shift)
#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
static void flow_cache_new_hashrnd(unsigned long arg)
{
struct flow_cache *fc = (void *) arg;
int i;
for_each_possible_cpu(i)
per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;
fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
add_timer(&fc->rnd_timer);
}
static int flow_entry_valid(struct flow_cache_entry *fle,
struct netns_xfrm *xfrm)
{
if (atomic_read(&xfrm->flow_cache_genid) != fle->genid)
return 0;
if (fle->object && !fle->object->ops->check(fle->object))
return 0;
return 1;
}
static void flow_entry_kill(struct flow_cache_entry *fle,
struct netns_xfrm *xfrm)
{
if (fle->object)
fle->object->ops->delete(fle->object);
kmem_cache_free(flow_cachep, fle);
}
static void flow_cache_gc_task(struct work_struct *work)
{
struct list_head gc_list;
struct flow_cache_entry *fce, *n;
struct netns_xfrm *xfrm = container_of(work, struct netns_xfrm,
flow_cache_gc_work);
INIT_LIST_HEAD(&gc_list);
spin_lock_bh(&xfrm->flow_cache_gc_lock);
list_splice_tail_init(&xfrm->flow_cache_gc_list, &gc_list);
spin_unlock_bh(&xfrm->flow_cache_gc_lock);
list_for_each_entry_safe(fce, n, &gc_list, u.gc_list)
flow_entry_kill(fce, xfrm);
}
static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp,
int deleted, struct list_head *gc_list,
struct netns_xfrm *xfrm)
{
if (deleted) {
fcp->hash_count -= deleted;
spin_lock_bh(&xfrm->flow_cache_gc_lock);
list_splice_tail(gc_list, &xfrm->flow_cache_gc_list);
spin_unlock_bh(&xfrm->flow_cache_gc_lock);
schedule_work(&xfrm->flow_cache_gc_work);
}
}
static void __flow_cache_shrink(struct flow_cache *fc,
struct flow_cache_percpu *fcp,
int shrink_to)
{
struct flow_cache_entry *fle;
struct hlist_node *tmp;
LIST_HEAD(gc_list);
int i, deleted = 0;
struct netns_xfrm *xfrm = container_of(fc, struct netns_xfrm,
flow_cache_global);
for (i = 0; i < flow_cache_hash_size(fc); i++) {
int saved = 0;
hlist_for_each_entry_safe(fle, tmp,
&fcp->hash_table[i], u.hlist) {
if (saved < shrink_to &&
flow_entry_valid(fle, xfrm)) {
saved++;
} else {
deleted++;
hlist_del(&fle->u.hlist);
list_add_tail(&fle->u.gc_list, &gc_list);
}
}
}
flow_cache_queue_garbage(fcp, deleted, &gc_list, xfrm);
}
static void flow_cache_shrink(struct flow_cache *fc,
struct flow_cache_percpu *fcp)
{
int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);
__flow_cache_shrink(fc, fcp, shrink_to);
}
static void flow_new_hash_rnd(struct flow_cache *fc,
struct flow_cache_percpu *fcp)
{
get_random_bytes(&fcp->hash_rnd, sizeof(u32));
fcp->hash_rnd_recalc = 0;
__flow_cache_shrink(fc, fcp, 0);
}
static u32 flow_hash_code(struct flow_cache *fc,
struct flow_cache_percpu *fcp,
const struct flowi *key,
size_t keysize)
{
const u32 *k = (const u32 *) key;
const u32 length = keysize * sizeof(flow_compare_t) / sizeof(u32);
return jhash2(k, length, fcp->hash_rnd)
& (flow_cache_hash_size(fc) - 1);
}
/* I hear what you're saying, use memcmp. But memcmp cannot make
* important assumptions that we can here, such as alignment.
*/
static int flow_key_compare(const struct flowi *key1, const struct flowi *key2,
size_t keysize)
{
const flow_compare_t *k1, *k1_lim, *k2;
k1 = (const flow_compare_t *) key1;
k1_lim = k1 + keysize;
k2 = (const flow_compare_t *) key2;
do {
if (*k1++ != *k2++)
return 1;
} while (k1 < k1_lim);
return 0;
}
struct flow_cache_object *
flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir,
flow_resolve_t resolver, void *ctx)
{
struct flow_cache *fc = &net->xfrm.flow_cache_global;
struct flow_cache_percpu *fcp;
struct flow_cache_entry *fle, *tfle;
struct flow_cache_object *flo;
size_t keysize;
unsigned int hash;
local_bh_disable();
fcp = this_cpu_ptr(fc->percpu);
fle = NULL;
flo = NULL;
keysize = flow_key_size(family);
if (!keysize)
goto nocache;
/* Packet really early in init? Making flow_cache_init a
* pre-smp initcall would solve this. --RR */
if (!fcp->hash_table)
goto nocache;
if (fcp->hash_rnd_recalc)
flow_new_hash_rnd(fc, fcp);
hash = flow_hash_code(fc, fcp, key, keysize);
hlist_for_each_entry(tfle, &fcp->hash_table[hash], u.hlist) {
if (tfle->net == net &&
tfle->family == family &&
tfle->dir == dir &&
flow_key_compare(key, &tfle->key, keysize) == 0) {
fle = tfle;
break;
}
}
if (unlikely(!fle)) {
if (fcp->hash_count > fc->high_watermark)
flow_cache_shrink(fc, fcp);
fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
if (fle) {
fle->net = net;
fle->family = family;
fle->dir = dir;
memcpy(&fle->key, key, keysize * sizeof(flow_compare_t));
fle->object = NULL;
hlist_add_head(&fle->u.hlist, &fcp->hash_table[hash]);
fcp->hash_count++;
}
} else if (likely(fle->genid == atomic_read(&net->xfrm.flow_cache_genid))) {
flo = fle->object;
if (!flo)
goto ret_object;
flo = flo->ops->get(flo);
if (flo)
goto ret_object;
} else if (fle->object) {
flo = fle->object;
flo->ops->delete(flo);
fle->object = NULL;
}
nocache:
flo = NULL;
if (fle) {
flo = fle->object;
fle->object = NULL;
}
flo = resolver(net, key, family, dir, flo, ctx);
if (fle) {
fle->genid = atomic_read(&net->xfrm.flow_cache_genid);
if (!IS_ERR(flo))
fle->object = flo;
else
fle->genid--;
} else {
if (!IS_ERR_OR_NULL(flo))
flo->ops->delete(flo);
}
ret_object:
local_bh_enable();
return flo;
}
EXPORT_SYMBOL(flow_cache_lookup);
static void flow_cache_flush_tasklet(unsigned long data)
{
struct flow_flush_info *info = (void *)data;
struct flow_cache *fc = info->cache;
struct flow_cache_percpu *fcp;
struct flow_cache_entry *fle;
struct hlist_node *tmp;
LIST_HEAD(gc_list);
int i, deleted = 0;
struct netns_xfrm *xfrm = container_of(fc, struct netns_xfrm,
flow_cache_global);
fcp = this_cpu_ptr(fc->percpu);
for (i = 0; i < flow_cache_hash_size(fc); i++) {
hlist_for_each_entry_safe(fle, tmp,
&fcp->hash_table[i], u.hlist) {
if (flow_entry_valid(fle, xfrm))
continue;
deleted++;
hlist_del(&fle->u.hlist);
list_add_tail(&fle->u.gc_list, &gc_list);
}
}
flow_cache_queue_garbage(fcp, deleted, &gc_list, xfrm);
if (atomic_dec_and_test(&info->cpuleft))
complete(&info->completion);
}
/*
* Return whether a cpu needs flushing. Conservatively, we assume
* the presence of any entries means the core may require flushing,
* since the flow_cache_ops.check() function may assume it's running
* on the same core as the per-cpu cache component.
*/
static int flow_cache_percpu_empty(struct flow_cache *fc, int cpu)
{
struct flow_cache_percpu *fcp;
int i;
fcp = per_cpu_ptr(fc->percpu, cpu);
for (i = 0; i < flow_cache_hash_size(fc); i++)
if (!hlist_empty(&fcp->hash_table[i]))
return 0;
return 1;
}
static void flow_cache_flush_per_cpu(void *data)
{
struct flow_flush_info *info = data;
struct tasklet_struct *tasklet;
tasklet = &this_cpu_ptr(info->cache->percpu)->flush_tasklet;
tasklet->data = (unsigned long)info;
tasklet_schedule(tasklet);
}
void flow_cache_flush(struct net *net)
{
struct flow_flush_info info;
cpumask_var_t mask;
int i, self;
/* Track which cpus need flushing to avoid disturbing all cores. */
if (!alloc_cpumask_var(&mask, GFP_KERNEL))
return;
cpumask_clear(mask);
/* Don't want cpus going down or up during this. */
get_online_cpus();
mutex_lock(&net->xfrm.flow_flush_sem);
info.cache = &net->xfrm.flow_cache_global;
for_each_online_cpu(i)
if (!flow_cache_percpu_empty(info.cache, i))
cpumask_set_cpu(i, mask);
atomic_set(&info.cpuleft, cpumask_weight(mask));
if (atomic_read(&info.cpuleft) == 0)
goto done;
init_completion(&info.completion);
local_bh_disable();
self = cpumask_test_and_clear_cpu(smp_processor_id(), mask);
on_each_cpu_mask(mask, flow_cache_flush_per_cpu, &info, 0);
if (self)
flow_cache_flush_tasklet((unsigned long)&info);
local_bh_enable();
wait_for_completion(&info.completion);
done:
mutex_unlock(&net->xfrm.flow_flush_sem);
put_online_cpus();
free_cpumask_var(mask);
}
static void flow_cache_flush_task(struct work_struct *work)
{
struct netns_xfrm *xfrm = container_of(work, struct netns_xfrm,
flow_cache_gc_work);
struct net *net = container_of(xfrm, struct net, xfrm);
flow_cache_flush(net);
}
void flow_cache_flush_deferred(struct net *net)
{
schedule_work(&net->xfrm.flow_cache_flush_work);
}
static int flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
{
struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
size_t sz = sizeof(struct hlist_head) * flow_cache_hash_size(fc);
if (!fcp->hash_table) {
fcp->hash_table = kzalloc_node(sz, GFP_KERNEL, cpu_to_node(cpu));
if (!fcp->hash_table) {
pr_err("NET: failed to allocate flow cache sz %zu\n", sz);
return -ENOMEM;
}
fcp->hash_rnd_recalc = 1;
fcp->hash_count = 0;
tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
}
return 0;
}
static int flow_cache_cpu(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
struct flow_cache *fc = container_of(nfb, struct flow_cache,
hotcpu_notifier);
int res, cpu = (unsigned long) hcpu;
struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
res = flow_cache_cpu_prepare(fc, cpu);
if (res)
return notifier_from_errno(res);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
__flow_cache_shrink(fc, fcp, 0);
break;
}
return NOTIFY_OK;
}
int flow_cache_init(struct net *net)
{
int i;
struct flow_cache *fc = &net->xfrm.flow_cache_global;
if (!flow_cachep)
flow_cachep = kmem_cache_create("flow_cache",
sizeof(struct flow_cache_entry),
0, SLAB_PANIC, NULL);
spin_lock_init(&net->xfrm.flow_cache_gc_lock);
INIT_LIST_HEAD(&net->xfrm.flow_cache_gc_list);
INIT_WORK(&net->xfrm.flow_cache_gc_work, flow_cache_gc_task);
INIT_WORK(&net->xfrm.flow_cache_flush_work, flow_cache_flush_task);
mutex_init(&net->xfrm.flow_flush_sem);
fc->hash_shift = 10;
fc->low_watermark = 2 * flow_cache_hash_size(fc);
fc->high_watermark = 4 * flow_cache_hash_size(fc);
fc->percpu = alloc_percpu(struct flow_cache_percpu);
if (!fc->percpu)
return -ENOMEM;
cpu_notifier_register_begin();
for_each_online_cpu(i) {
if (flow_cache_cpu_prepare(fc, i))
goto err;
}
fc->hotcpu_notifier = (struct notifier_block){
.notifier_call = flow_cache_cpu,
};
__register_hotcpu_notifier(&fc->hotcpu_notifier);
cpu_notifier_register_done();
setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
(unsigned long) fc);
fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
add_timer(&fc->rnd_timer);
return 0;
err:
for_each_possible_cpu(i) {
struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
kfree(fcp->hash_table);
fcp->hash_table = NULL;
}
cpu_notifier_register_done();
free_percpu(fc->percpu);
fc->percpu = NULL;
return -ENOMEM;
}
EXPORT_SYMBOL(flow_cache_init);
void flow_cache_fini(struct net *net)
{
int i;
struct flow_cache *fc = &net->xfrm.flow_cache_global;
del_timer_sync(&fc->rnd_timer);
unregister_hotcpu_notifier(&fc->hotcpu_notifier);
for_each_possible_cpu(i) {
struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
kfree(fcp->hash_table);
fcp->hash_table = NULL;
}
free_percpu(fc->percpu);
fc->percpu = NULL;
}
EXPORT_SYMBOL(flow_cache_fini);