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ipvs: convert dh scheduler to rcu
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Use the new add_dest and del_dest methods
to reassign dests.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
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Julian Anastasov authored and Pablo Neira Ayuso committed Apr 1, 2013
1 parent fca9c20 commit 8f3d002
Showing 1 changed file with 45 additions and 36 deletions.
81 changes: 45 additions & 36 deletions net/netfilter/ipvs/ip_vs_dh.c
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Original file line number Diff line number Diff line change
Expand Up @@ -51,7 +51,7 @@
* IPVS DH bucket
*/
struct ip_vs_dh_bucket {
struct ip_vs_dest *dest; /* real server (cache) */
struct ip_vs_dest __rcu *dest; /* real server (cache) */
};

/*
Expand All @@ -64,6 +64,10 @@ struct ip_vs_dh_bucket {
#define IP_VS_DH_TAB_SIZE (1 << IP_VS_DH_TAB_BITS)
#define IP_VS_DH_TAB_MASK (IP_VS_DH_TAB_SIZE - 1)

struct ip_vs_dh_state {
struct ip_vs_dh_bucket buckets[IP_VS_DH_TAB_SIZE];
struct rcu_head rcu_head;
};

/*
* Returns hash value for IPVS DH entry
Expand All @@ -85,36 +89,40 @@ static inline unsigned int ip_vs_dh_hashkey(int af, const union nf_inet_addr *ad
* Get ip_vs_dest associated with supplied parameters.
*/
static inline struct ip_vs_dest *
ip_vs_dh_get(int af, struct ip_vs_dh_bucket *tbl,
const union nf_inet_addr *addr)
ip_vs_dh_get(int af, struct ip_vs_dh_state *s, const union nf_inet_addr *addr)
{
return (tbl[ip_vs_dh_hashkey(af, addr)]).dest;
return rcu_dereference(s->buckets[ip_vs_dh_hashkey(af, addr)].dest);
}


/*
* Assign all the hash buckets of the specified table with the service.
*/
static int
ip_vs_dh_assign(struct ip_vs_dh_bucket *tbl, struct ip_vs_service *svc)
ip_vs_dh_reassign(struct ip_vs_dh_state *s, struct ip_vs_service *svc)
{
int i;
struct ip_vs_dh_bucket *b;
struct list_head *p;
struct ip_vs_dest *dest;
bool empty;

b = tbl;
b = &s->buckets[0];
p = &svc->destinations;
empty = list_empty(p);
for (i=0; i<IP_VS_DH_TAB_SIZE; i++) {
if (list_empty(p)) {
b->dest = NULL;
} else {
dest = rcu_dereference_protected(b->dest, 1);
if (dest)
ip_vs_dest_put(dest);
if (empty)
RCU_INIT_POINTER(b->dest, NULL);
else {
if (p == &svc->destinations)
p = p->next;

dest = list_entry(p, struct ip_vs_dest, n_list);
atomic_inc(&dest->refcnt);
b->dest = dest;
ip_vs_dest_hold(dest);
RCU_INIT_POINTER(b->dest, dest);

p = p->next;
}
Expand All @@ -127,16 +135,18 @@ ip_vs_dh_assign(struct ip_vs_dh_bucket *tbl, struct ip_vs_service *svc)
/*
* Flush all the hash buckets of the specified table.
*/
static void ip_vs_dh_flush(struct ip_vs_dh_bucket *tbl)
static void ip_vs_dh_flush(struct ip_vs_dh_state *s)
{
int i;
struct ip_vs_dh_bucket *b;
struct ip_vs_dest *dest;

b = tbl;
b = &s->buckets[0];
for (i=0; i<IP_VS_DH_TAB_SIZE; i++) {
if (b->dest) {
atomic_dec(&b->dest->refcnt);
b->dest = NULL;
dest = rcu_dereference_protected(b->dest, 1);
if (dest) {
ip_vs_dest_put(dest);
RCU_INIT_POINTER(b->dest, NULL);
}
b++;
}
Expand All @@ -145,51 +155,48 @@ static void ip_vs_dh_flush(struct ip_vs_dh_bucket *tbl)

static int ip_vs_dh_init_svc(struct ip_vs_service *svc)
{
struct ip_vs_dh_bucket *tbl;
struct ip_vs_dh_state *s;

/* allocate the DH table for this service */
tbl = kmalloc(sizeof(struct ip_vs_dh_bucket)*IP_VS_DH_TAB_SIZE,
GFP_KERNEL);
if (tbl == NULL)
s = kzalloc(sizeof(struct ip_vs_dh_state), GFP_KERNEL);
if (s == NULL)
return -ENOMEM;

svc->sched_data = tbl;
svc->sched_data = s;
IP_VS_DBG(6, "DH hash table (memory=%Zdbytes) allocated for "
"current service\n",
sizeof(struct ip_vs_dh_bucket)*IP_VS_DH_TAB_SIZE);

/* assign the hash buckets with the updated service */
ip_vs_dh_assign(tbl, svc);
/* assign the hash buckets with current dests */
ip_vs_dh_reassign(s, svc);

return 0;
}


static int ip_vs_dh_done_svc(struct ip_vs_service *svc)
{
struct ip_vs_dh_bucket *tbl = svc->sched_data;
struct ip_vs_dh_state *s = svc->sched_data;

/* got to clean up hash buckets here */
ip_vs_dh_flush(tbl);
ip_vs_dh_flush(s);

/* release the table itself */
kfree(svc->sched_data);
kfree_rcu(s, rcu_head);
IP_VS_DBG(6, "DH hash table (memory=%Zdbytes) released\n",
sizeof(struct ip_vs_dh_bucket)*IP_VS_DH_TAB_SIZE);

return 0;
}


static int ip_vs_dh_update_svc(struct ip_vs_service *svc)
static int ip_vs_dh_dest_changed(struct ip_vs_service *svc,
struct ip_vs_dest *dest)
{
struct ip_vs_dh_bucket *tbl = svc->sched_data;

/* got to clean up hash buckets here */
ip_vs_dh_flush(tbl);
struct ip_vs_dh_state *s = svc->sched_data;

/* assign the hash buckets with the updated service */
ip_vs_dh_assign(tbl, svc);
ip_vs_dh_reassign(s, svc);

return 0;
}
Expand All @@ -212,19 +219,20 @@ static struct ip_vs_dest *
ip_vs_dh_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
{
struct ip_vs_dest *dest;
struct ip_vs_dh_bucket *tbl;
struct ip_vs_dh_state *s;
struct ip_vs_iphdr iph;

ip_vs_fill_iph_addr_only(svc->af, skb, &iph);

IP_VS_DBG(6, "%s(): Scheduling...\n", __func__);

tbl = (struct ip_vs_dh_bucket *)svc->sched_data;
dest = ip_vs_dh_get(svc->af, tbl, &iph.daddr);
s = (struct ip_vs_dh_state *) svc->sched_data;
dest = ip_vs_dh_get(svc->af, s, &iph.daddr);
if (!dest
|| !(dest->flags & IP_VS_DEST_F_AVAILABLE)
|| atomic_read(&dest->weight) <= 0
|| is_overloaded(dest)) {
ip_vs_scheduler_err(svc, "no destination available");
return NULL;
}

Expand All @@ -248,7 +256,8 @@ static struct ip_vs_scheduler ip_vs_dh_scheduler =
.n_list = LIST_HEAD_INIT(ip_vs_dh_scheduler.n_list),
.init_service = ip_vs_dh_init_svc,
.done_service = ip_vs_dh_done_svc,
.update_service = ip_vs_dh_update_svc,
.add_dest = ip_vs_dh_dest_changed,
.del_dest = ip_vs_dh_dest_changed,
.schedule = ip_vs_dh_schedule,
};

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