#include <net/inet_frag.h>
#include <net/inet_ecn.h>
+#define INETFRAGS_EVICT_BUCKETS 128
+#define INETFRAGS_EVICT_MAX 512
+
+/* don't rebuild inetfrag table with new secret more often than this */
+#define INETFRAGS_MIN_REBUILD_INTERVAL (5 * HZ)
+
/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
* Value : 0xff if frame should be dropped.
* 0 or INET_ECN_CE value, to be ORed in to final iph->tos field
};
EXPORT_SYMBOL(ip_frag_ecn_table);
-static void inet_frag_secret_rebuild(unsigned long dummy)
+static unsigned int
+inet_frag_hashfn(const struct inet_frags *f, const struct inet_frag_queue *q)
+{
+ return f->hashfn(q) & (INETFRAGS_HASHSZ - 1);
+}
+
+static bool inet_frag_may_rebuild(struct inet_frags *f)
+{
+ return time_after(jiffies,
+ f->last_rebuild_jiffies + INETFRAGS_MIN_REBUILD_INTERVAL);
+}
+
+static void inet_frag_secret_rebuild(struct inet_frags *f)
{
- struct inet_frags *f = (struct inet_frags *)dummy;
- unsigned long now = jiffies;
int i;
- /* Per bucket lock NOT needed here, due to write lock protection */
- write_lock(&f->lock);
+ write_seqlock_bh(&f->rnd_seqlock);
+
+ if (!inet_frag_may_rebuild(f))
+ goto out;
get_random_bytes(&f->rnd, sizeof(u32));
+
for (i = 0; i < INETFRAGS_HASHSZ; i++) {
struct inet_frag_bucket *hb;
struct inet_frag_queue *q;
struct hlist_node *n;
hb = &f->hash[i];
+ spin_lock(&hb->chain_lock);
+
hlist_for_each_entry_safe(q, n, &hb->chain, list) {
- unsigned int hval = f->hashfn(q);
+ unsigned int hval = inet_frag_hashfn(f, q);
if (hval != i) {
struct inet_frag_bucket *hb_dest;
/* Relink to new hash chain. */
hb_dest = &f->hash[hval];
+
+ /* This is the only place where we take
+ * another chain_lock while already holding
+ * one. As this will not run concurrently,
+ * we cannot deadlock on hb_dest lock below, if its
+ * already locked it will be released soon since
+ * other caller cannot be waiting for hb lock
+ * that we've taken above.
+ */
+ spin_lock_nested(&hb_dest->chain_lock,
+ SINGLE_DEPTH_NESTING);
hlist_add_head(&q->list, &hb_dest->chain);
+ spin_unlock(&hb_dest->chain_lock);
}
}
+ spin_unlock(&hb->chain_lock);
+ }
+
+ f->rebuild = false;
+ f->last_rebuild_jiffies = jiffies;
+out:
+ write_sequnlock_bh(&f->rnd_seqlock);
+}
+
+static bool inet_fragq_should_evict(const struct inet_frag_queue *q)
+{
+ return q->net->low_thresh == 0 ||
+ frag_mem_limit(q->net) >= q->net->low_thresh;
+}
+
+static unsigned int
+inet_evict_bucket(struct inet_frags *f, struct inet_frag_bucket *hb)
+{
+ struct inet_frag_queue *fq;
+ struct hlist_node *n;
+ unsigned int evicted = 0;
+ HLIST_HEAD(expired);
+
+evict_again:
+ spin_lock(&hb->chain_lock);
+
+ hlist_for_each_entry_safe(fq, n, &hb->chain, list) {
+ if (!inet_fragq_should_evict(fq))
+ continue;
+
+ if (!del_timer(&fq->timer)) {
+ /* q expiring right now thus increment its refcount so
+ * it won't be freed under us and wait until the timer
+ * has finished executing then destroy it
+ */
+ atomic_inc(&fq->refcnt);
+ spin_unlock(&hb->chain_lock);
+ del_timer_sync(&fq->timer);
+ WARN_ON(atomic_read(&fq->refcnt) != 1);
+ inet_frag_put(fq, f);
+ goto evict_again;
+ }
+
+ fq->flags |= INET_FRAG_EVICTED;
+ hlist_del(&fq->list);
+ hlist_add_head(&fq->list, &expired);
+ ++evicted;
}
- write_unlock(&f->lock);
- mod_timer(&f->secret_timer, now + f->secret_interval);
+ spin_unlock(&hb->chain_lock);
+
+ hlist_for_each_entry_safe(fq, n, &expired, list)
+ f->frag_expire((unsigned long) fq);
+
+ return evicted;
}
-void inet_frags_init(struct inet_frags *f)
+static void inet_frag_worker(struct work_struct *work)
+{
+ unsigned int budget = INETFRAGS_EVICT_BUCKETS;
+ unsigned int i, evicted = 0;
+ struct inet_frags *f;
+
+ f = container_of(work, struct inet_frags, frags_work);
+
+ BUILD_BUG_ON(INETFRAGS_EVICT_BUCKETS >= INETFRAGS_HASHSZ);
+
+ local_bh_disable();
+
+ for (i = ACCESS_ONCE(f->next_bucket); budget; --budget) {
+ evicted += inet_evict_bucket(f, &f->hash[i]);
+ i = (i + 1) & (INETFRAGS_HASHSZ - 1);
+ if (evicted > INETFRAGS_EVICT_MAX)
+ break;
+ }
+
+ f->next_bucket = i;
+
+ local_bh_enable();
+
+ if (f->rebuild && inet_frag_may_rebuild(f))
+ inet_frag_secret_rebuild(f);
+}
+
+static void inet_frag_schedule_worker(struct inet_frags *f)
+{
+ if (unlikely(!work_pending(&f->frags_work)))
+ schedule_work(&f->frags_work);
+}
+
+int inet_frags_init(struct inet_frags *f)
{
int i;
+ INIT_WORK(&f->frags_work, inet_frag_worker);
+
for (i = 0; i < INETFRAGS_HASHSZ; i++) {
struct inet_frag_bucket *hb = &f->hash[i];
spin_lock_init(&hb->chain_lock);
INIT_HLIST_HEAD(&hb->chain);
}
- rwlock_init(&f->lock);
- setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
- (unsigned long)f);
- f->secret_timer.expires = jiffies + f->secret_interval;
- add_timer(&f->secret_timer);
+ seqlock_init(&f->rnd_seqlock);
+ f->last_rebuild_jiffies = 0;
+ f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0,
+ NULL);
+ if (!f->frags_cachep)
+ return -ENOMEM;
+
+ return 0;
}
EXPORT_SYMBOL(inet_frags_init);
void inet_frags_init_net(struct netns_frags *nf)
{
- nf->nqueues = 0;
init_frag_mem_limit(nf);
- INIT_LIST_HEAD(&nf->lru_list);
- spin_lock_init(&nf->lru_lock);
}
EXPORT_SYMBOL(inet_frags_init_net);
void inet_frags_fini(struct inet_frags *f)
{
- del_timer(&f->secret_timer);
+ cancel_work_sync(&f->frags_work);
+ kmem_cache_destroy(f->frags_cachep);
}
EXPORT_SYMBOL(inet_frags_fini);
void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f)
{
- nf->low_thresh = 0;
+ unsigned int seq;
+ int i;
+ nf->low_thresh = 0;
local_bh_disable();
- inet_frag_evictor(nf, f, true);
+
+evict_again:
+ seq = read_seqbegin(&f->rnd_seqlock);
+
+ for (i = 0; i < INETFRAGS_HASHSZ ; i++)
+ inet_evict_bucket(f, &f->hash[i]);
+
+ if (read_seqretry(&f->rnd_seqlock, seq))
+ goto evict_again;
+
local_bh_enable();
percpu_counter_destroy(&nf->mem);
}
EXPORT_SYMBOL(inet_frags_exit_net);
-static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
+static struct inet_frag_bucket *
+get_frag_bucket_locked(struct inet_frag_queue *fq, struct inet_frags *f)
+__acquires(hb->chain_lock)
{
struct inet_frag_bucket *hb;
- unsigned int hash;
+ unsigned int seq, hash;
+
+ restart:
+ seq = read_seqbegin(&f->rnd_seqlock);
- read_lock(&f->lock);
- hash = f->hashfn(fq);
+ hash = inet_frag_hashfn(f, fq);
hb = &f->hash[hash];
spin_lock(&hb->chain_lock);
+ if (read_seqretry(&f->rnd_seqlock, seq)) {
+ spin_unlock(&hb->chain_lock);
+ goto restart;
+ }
+
+ return hb;
+}
+
+static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
+{
+ struct inet_frag_bucket *hb;
+
+ hb = get_frag_bucket_locked(fq, f);
hlist_del(&fq->list);
spin_unlock(&hb->chain_lock);
-
- read_unlock(&f->lock);
- inet_frag_lru_del(fq);
}
void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
if (del_timer(&fq->timer))
atomic_dec(&fq->refcnt);
- if (!(fq->last_in & INET_FRAG_COMPLETE)) {
+ if (!(fq->flags & INET_FRAG_COMPLETE)) {
fq_unlink(fq, f);
atomic_dec(&fq->refcnt);
- fq->last_in |= INET_FRAG_COMPLETE;
+ fq->flags |= INET_FRAG_COMPLETE;
}
}
EXPORT_SYMBOL(inet_frag_kill);
static inline void frag_kfree_skb(struct netns_frags *nf, struct inet_frags *f,
- struct sk_buff *skb)
+ struct sk_buff *skb)
{
if (f->skb_free)
f->skb_free(skb);
kfree_skb(skb);
}
-void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f,
- int *work)
+void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f)
{
struct sk_buff *fp;
struct netns_frags *nf;
unsigned int sum, sum_truesize = 0;
- WARN_ON(!(q->last_in & INET_FRAG_COMPLETE));
+ WARN_ON(!(q->flags & INET_FRAG_COMPLETE));
WARN_ON(del_timer(&q->timer) != 0);
/* Release all fragment data. */
fp = xp;
}
sum = sum_truesize + f->qsize;
- if (work)
- *work -= sum;
sub_frag_mem_limit(q, sum);
if (f->destructor)
f->destructor(q);
- kfree(q);
-
+ kmem_cache_free(f->frags_cachep, q);
}
EXPORT_SYMBOL(inet_frag_destroy);
-int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force)
-{
- struct inet_frag_queue *q;
- int work, evicted = 0;
-
- if (!force) {
- if (frag_mem_limit(nf) <= nf->high_thresh)
- return 0;
- }
-
- work = frag_mem_limit(nf) - nf->low_thresh;
- while (work > 0 || force) {
- spin_lock(&nf->lru_lock);
-
- if (list_empty(&nf->lru_list)) {
- spin_unlock(&nf->lru_lock);
- break;
- }
-
- q = list_first_entry(&nf->lru_list,
- struct inet_frag_queue, lru_list);
- atomic_inc(&q->refcnt);
- /* Remove q from list to avoid several CPUs grabbing it */
- list_del_init(&q->lru_list);
-
- spin_unlock(&nf->lru_lock);
-
- spin_lock(&q->lock);
- if (!(q->last_in & INET_FRAG_COMPLETE))
- inet_frag_kill(q, f);
- spin_unlock(&q->lock);
-
- if (atomic_dec_and_test(&q->refcnt))
- inet_frag_destroy(q, f, &work);
- evicted++;
- }
-
- return evicted;
-}
-EXPORT_SYMBOL(inet_frag_evictor);
-
static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf,
- struct inet_frag_queue *qp_in, struct inet_frags *f,
- void *arg)
+ struct inet_frag_queue *qp_in,
+ struct inet_frags *f,
+ void *arg)
{
- struct inet_frag_bucket *hb;
+ struct inet_frag_bucket *hb = get_frag_bucket_locked(qp_in, f);
struct inet_frag_queue *qp;
- unsigned int hash;
-
- read_lock(&f->lock); /* Protects against hash rebuild */
- /*
- * While we stayed w/o the lock other CPU could update
- * the rnd seed, so we need to re-calculate the hash
- * chain. Fortunatelly the qp_in can be used to get one.
- */
- hash = f->hashfn(qp_in);
- hb = &f->hash[hash];
- spin_lock(&hb->chain_lock);
#ifdef CONFIG_SMP
/* With SMP race we have to recheck hash table, because
- * such entry could be created on other cpu, while we
- * released the hash bucket lock.
+ * such entry could have been created on other cpu before
+ * we acquired hash bucket lock.
*/
hlist_for_each_entry(qp, &hb->chain, list) {
if (qp->net == nf && f->match(qp, arg)) {
atomic_inc(&qp->refcnt);
spin_unlock(&hb->chain_lock);
- read_unlock(&f->lock);
- qp_in->last_in |= INET_FRAG_COMPLETE;
+ qp_in->flags |= INET_FRAG_COMPLETE;
inet_frag_put(qp_in, f);
return qp;
}
atomic_inc(&qp->refcnt);
hlist_add_head(&qp->list, &hb->chain);
- inet_frag_lru_add(nf, qp);
+
spin_unlock(&hb->chain_lock);
- read_unlock(&f->lock);
return qp;
}
static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
- struct inet_frags *f, void *arg)
+ struct inet_frags *f,
+ void *arg)
{
struct inet_frag_queue *q;
- q = kzalloc(f->qsize, GFP_ATOMIC);
+ if (frag_mem_limit(nf) > nf->high_thresh) {
+ inet_frag_schedule_worker(f);
+ return NULL;
+ }
+
+ q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC);
if (q == NULL)
return NULL;
setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
spin_lock_init(&q->lock);
atomic_set(&q->refcnt, 1);
- INIT_LIST_HEAD(&q->lru_list);
return q;
}
static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
- struct inet_frags *f, void *arg)
+ struct inet_frags *f,
+ void *arg)
{
struct inet_frag_queue *q;
}
struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
- struct inet_frags *f, void *key, unsigned int hash)
- __releases(&f->lock)
+ struct inet_frags *f, void *key,
+ unsigned int hash)
{
struct inet_frag_bucket *hb;
struct inet_frag_queue *q;
int depth = 0;
+ if (frag_mem_limit(nf) > nf->low_thresh)
+ inet_frag_schedule_worker(f);
+
+ hash &= (INETFRAGS_HASHSZ - 1);
hb = &f->hash[hash];
spin_lock(&hb->chain_lock);
if (q->net == nf && f->match(q, key)) {
atomic_inc(&q->refcnt);
spin_unlock(&hb->chain_lock);
- read_unlock(&f->lock);
return q;
}
depth++;
}
spin_unlock(&hb->chain_lock);
- read_unlock(&f->lock);
if (depth <= INETFRAGS_MAXDEPTH)
return inet_frag_create(nf, f, key);
- else
- return ERR_PTR(-ENOBUFS);
+
+ if (inet_frag_may_rebuild(f)) {
+ if (!f->rebuild)
+ f->rebuild = true;
+ inet_frag_schedule_worker(f);
+ }
+
+ return ERR_PTR(-ENOBUFS);
}
EXPORT_SYMBOL(inet_frag_find);
projects / cascardo / linux.git / blobdiff