[XFRM]: Hash policies when non-prefixed.

This idea is from Alexey Kuznetsov.

It is common for policies to be non-prefixed.  And for
that case we can optimize lookups, insert, etc. quite
a bit.

For each direction, we have a dynamically sized policy
hash table for non-prefixed policies.  We also have a
hash table on policy->index.

For prefixed policies, we have a list per-direction which
we will consult on lookups when a non-prefix hashtable
lookup fails.

This still isn't as efficient as I would like it.  There
are four immediate problems:

1) Lots of excessive refcounting, which can be fixed just
   like xfrm_state was
2) We do 2 hash probes on insert, one to look for dups and
   one to allocate a unique policy->index.  Althought I wonder
   how much this matters since xfrm_state inserts do up to
   3 hash probes and that seems to perform fine.
3) xfrm_policy_insert() is very complex because of the priority
   ordering and entry replacement logic.
4) Lots of counter bumping, in addition to policy refcounts,
   in the form of xfrm_policy_count[].  This is merely used
   to let code path(s) know that some IPSEC rules exist.  So
   this count is indexed per-direction, maybe that is overkill.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 541 insertions, 140 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 1bcaae4adf3a..087a5443b051 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -22,6 +22,9 @@
 #include <linux/netdevice.h>
 #include <linux/netfilter.h>
 #include <linux/module.h>
+#include <linux/bootmem.h>
+#include <linux/vmalloc.h>
+#include <linux/cache.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
 
@@ -30,26 +33,8 @@ EXPORT_SYMBOL(xfrm_cfg_mutex);
 
 static DEFINE_RWLOCK(xfrm_policy_lock);
 
-struct xfrm_policy *xfrm_policy_list[XFRM_POLICY_MAX*2];
-EXPORT_SYMBOL(xfrm_policy_list);
-#ifdef CONFIG_XFRM_SUB_POLICY
-struct xfrm_policy *xfrm_policy_list_sub[XFRM_POLICY_MAX*2];
-EXPORT_SYMBOL(xfrm_policy_list_sub);
-
-#define XFRM_POLICY_LISTS(type) \
-        ((type == XFRM_POLICY_TYPE_SUB) ? xfrm_policy_list_sub : \
-         xfrm_policy_list)
-#define XFRM_POLICY_LISTHEAD(type, dir) \
-        ((type == XFRM_POLICY_TYPE_SUB) ? xfrm_policy_list_sub[dir] : \
-         xfrm_policy_list[dir])
-#define XFRM_POLICY_LISTHEADP(type, dir) \
-        ((type == XFRM_POLICY_TYPE_SUB) ? &xfrm_policy_list_sub[dir] : \
-         &xfrm_policy_list[dir])
-#else
-#define XFRM_POLICY_LISTS(type)              xfrm_policy_list
-#define XFRM_POLICY_LISTHEAD(type, dif)      xfrm_policy_list[dir]
-#define XFRM_POLICY_LISTHEADP(type, dif)     &xfrm_policy_list[dir]
-#endif
+unsigned int xfrm_policy_count[XFRM_POLICY_MAX*2];
+EXPORT_SYMBOL(xfrm_policy_count);
 
 static DEFINE_RWLOCK(xfrm_policy_afinfo_lock);
 static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO];
@@ -57,8 +42,7 @@ static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO];
 static kmem_cache_t *xfrm_dst_cache __read_mostly;
 
 static struct work_struct xfrm_policy_gc_work;
-static struct list_head xfrm_policy_gc_list =
-        LIST_HEAD_INIT(xfrm_policy_gc_list);
+static HLIST_HEAD(xfrm_policy_gc_list);
 static DEFINE_SPINLOCK(xfrm_policy_gc_lock);
 
 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
@@ -328,8 +312,10 @@ struct xfrm_policy *xfrm_policy_alloc(gfp_t gfp)
         policy = kzalloc(sizeof(struct xfrm_policy), gfp);
 
         if (policy) {
-                atomic_set(&policy->refcnt, 1);
+                INIT_HLIST_NODE(&policy->bydst);
+                INIT_HLIST_NODE(&policy->byidx);
                 rwlock_init(&policy->lock);
+                atomic_set(&policy->refcnt, 1);
                 init_timer(&policy->timer);
                 policy->timer.data = (unsigned long)policy;
                 policy->timer.function = xfrm_policy_timer;
@@ -375,17 +361,16 @@ static void xfrm_policy_gc_kill(struct xfrm_policy *policy)
 static void xfrm_policy_gc_task(void *data)
 {
         struct xfrm_policy *policy;
-        struct list_head *entry, *tmp;
-        struct list_head gc_list = LIST_HEAD_INIT(gc_list);
+        struct hlist_node *entry, *tmp;
+        struct hlist_head gc_list;
 
         spin_lock_bh(&xfrm_policy_gc_lock);
-        list_splice_init(&xfrm_policy_gc_list, &gc_list);
+        gc_list.first = xfrm_policy_gc_list.first;
+        INIT_HLIST_HEAD(&xfrm_policy_gc_list);
         spin_unlock_bh(&xfrm_policy_gc_lock);
 
-        list_for_each_safe(entry, tmp, &gc_list) {
-                policy = list_entry(entry, struct xfrm_policy, list);
+        hlist_for_each_entry_safe(policy, entry, tmp, &gc_list, bydst)
                 xfrm_policy_gc_kill(policy);
-        }
 }
 
 /* Rule must be locked. Release descentant resources, announce
@@ -407,70 +392,354 @@ static void xfrm_policy_kill(struct xfrm_policy *policy)
         }
 
         spin_lock(&xfrm_policy_gc_lock);
-        list_add(&policy->list, &xfrm_policy_gc_list);
+        hlist_add_head(&policy->bydst, &xfrm_policy_gc_list);
         spin_unlock(&xfrm_policy_gc_lock);
 
         schedule_work(&xfrm_policy_gc_work);
 }
 
+struct xfrm_policy_hash {
+        struct hlist_head       *table;
+        unsigned int            hmask;
+};
+
+static struct hlist_head xfrm_policy_inexact[XFRM_POLICY_MAX*2];
+static struct xfrm_policy_hash xfrm_policy_bydst[XFRM_POLICY_MAX*2] __read_mostly;
+static struct hlist_head *xfrm_policy_byidx __read_mostly;
+static unsigned int xfrm_idx_hmask __read_mostly;
+static unsigned int xfrm_policy_hashmax __read_mostly = 1 * 1024 * 1024;
+
+static inline unsigned int __idx_hash(u32 index, unsigned int hmask)
+{
+        return (index ^ (index >> 8)) & hmask;
+}
+
+static inline unsigned int idx_hash(u32 index)
+{
+        return __idx_hash(index, xfrm_idx_hmask);
+}
+
+static inline unsigned int __sel_hash(struct xfrm_selector *sel, unsigned short family, unsigned int hmask)
+{
+        xfrm_address_t *daddr = &sel->daddr;
+        xfrm_address_t *saddr = &sel->saddr;
+        unsigned int h = 0;
+
+        switch (family) {
+        case AF_INET:
+                if (sel->prefixlen_d != 32 ||
+                    sel->prefixlen_s != 32)
+                        return hmask + 1;
+
+                h = ntohl(daddr->a4 ^ saddr->a4);
+                break;
+
+        case AF_INET6:
+                if (sel->prefixlen_d != 128 ||
+                    sel->prefixlen_s != 128)
+                        return hmask + 1;
+
+                h = ntohl(daddr->a6[2] ^ daddr->a6[3] ^
+                          saddr->a6[2] ^ saddr->a6[3]);
+                break;
+        };
+        h ^= (h >> 16);
+        return h & hmask;
+}
+
+static inline unsigned int __addr_hash(xfrm_address_t *daddr, xfrm_address_t *saddr, unsigned short family, unsigned int hmask)
+{
+        unsigned int h = 0;
+
+        switch (family) {
+        case AF_INET:
+                h = ntohl(daddr->a4 ^ saddr->a4);
+                break;
+
+        case AF_INET6:
+                h = ntohl(daddr->a6[2] ^ daddr->a6[3] ^
+                          saddr->a6[2] ^ saddr->a6[3]);
+                break;
+        };
+        h ^= (h >> 16);
+        return h & hmask;
+}
+
+static struct hlist_head *policy_hash_bysel(struct xfrm_selector *sel, unsigned short family, int dir)
+{
+        unsigned int hmask = xfrm_policy_bydst[dir].hmask;
+        unsigned int hash = __sel_hash(sel, family, hmask);
+
+        return (hash == hmask + 1 ?
+                &xfrm_policy_inexact[dir] :
+                xfrm_policy_bydst[dir].table + hash);
+}
+
+static struct hlist_head *policy_hash_direct(xfrm_address_t *daddr, xfrm_address_t *saddr, unsigned short family, int dir)
+{
+        unsigned int hmask = xfrm_policy_bydst[dir].hmask;
+        unsigned int hash = __addr_hash(daddr, saddr, family, hmask);
+
+        return xfrm_policy_bydst[dir].table + hash;
+}
+
+static struct hlist_head *xfrm_policy_hash_alloc(unsigned int sz)
+{
+        struct hlist_head *n;
+
+        if (sz <= PAGE_SIZE)
+                n = kmalloc(sz, GFP_KERNEL);
+        else if (hashdist)
+                n = __vmalloc(sz, GFP_KERNEL, PAGE_KERNEL);
+        else
+                n = (struct hlist_head *)
+                        __get_free_pages(GFP_KERNEL, get_order(sz));
+
+        if (n)
+                memset(n, 0, sz);
+
+        return n;
+}
+
+static void xfrm_policy_hash_free(struct hlist_head *n, unsigned int sz)
+{
+        if (sz <= PAGE_SIZE)
+                kfree(n);
+        else if (hashdist)
+                vfree(n);
+        else
+                free_pages((unsigned long)n, get_order(sz));
+}
+
+static void xfrm_dst_hash_transfer(struct hlist_head *list,
+                                   struct hlist_head *ndsttable,
+                                   unsigned int nhashmask)
+{
+        struct hlist_node *entry, *tmp;
+        struct xfrm_policy *pol;
+
+        hlist_for_each_entry_safe(pol, entry, tmp, list, bydst) {
+                unsigned int h;
+
+                h = __addr_hash(&pol->selector.daddr, &pol->selector.saddr,
+                                pol->family, nhashmask);
+                hlist_add_head(&pol->bydst, ndsttable+h);
+        }
+}
+
+static void xfrm_idx_hash_transfer(struct hlist_head *list,
+                                   struct hlist_head *nidxtable,
+                                   unsigned int nhashmask)
+{
+        struct hlist_node *entry, *tmp;
+        struct xfrm_policy *pol;
+
+        hlist_for_each_entry_safe(pol, entry, tmp, list, byidx) {
+                unsigned int h;
+
+                h = __idx_hash(pol->index, nhashmask);
+                hlist_add_head(&pol->byidx, nidxtable+h);
+        }
+}
+
+static unsigned long xfrm_new_hash_mask(unsigned int old_hmask)
+{
+        return ((old_hmask + 1) << 1) - 1;
+}
+
+static void xfrm_bydst_resize(int dir)
+{
+        unsigned int hmask = xfrm_policy_bydst[dir].hmask;
+        unsigned int nhashmask = xfrm_new_hash_mask(hmask);
+        unsigned int nsize = (nhashmask + 1) * sizeof(struct hlist_head);
+        struct hlist_head *odst = xfrm_policy_bydst[dir].table;
+        struct hlist_head *ndst = xfrm_policy_hash_alloc(nsize);
+        int i;
+
+        if (!ndst)
+                return;
+
+        write_lock_bh(&xfrm_policy_lock);
+
+        for (i = hmask; i >= 0; i--)
+                xfrm_dst_hash_transfer(odst + i, ndst, nhashmask);
+
+        xfrm_policy_bydst[dir].table = ndst;
+        xfrm_policy_bydst[dir].hmask = nhashmask;
+
+        write_unlock_bh(&xfrm_policy_lock);
+
+        xfrm_policy_hash_free(odst, (hmask + 1) * sizeof(struct hlist_head));
+}
+
+static void xfrm_byidx_resize(int total)
+{
+        unsigned int hmask = xfrm_idx_hmask;
+        unsigned int nhashmask = xfrm_new_hash_mask(hmask);
+        unsigned int nsize = (nhashmask + 1) * sizeof(struct hlist_head);
+        struct hlist_head *oidx = xfrm_policy_byidx;
+        struct hlist_head *nidx = xfrm_policy_hash_alloc(nsize);
+        int i;
+
+        if (!nidx)
+                return;
+
+        write_lock_bh(&xfrm_policy_lock);
+
+        for (i = hmask; i >= 0; i--)
+                xfrm_idx_hash_transfer(oidx + i, nidx, nhashmask);
+
+        xfrm_policy_byidx = nidx;
+        xfrm_idx_hmask = nhashmask;
+
+        write_unlock_bh(&xfrm_policy_lock);
+
+        xfrm_policy_hash_free(oidx, (hmask + 1) * sizeof(struct hlist_head));
+}
+
+static inline int xfrm_bydst_should_resize(int dir, int *total)
+{
+        unsigned int cnt = xfrm_policy_count[dir];
+        unsigned int hmask = xfrm_policy_bydst[dir].hmask;
+
+        if (total)
+                *total += cnt;
+
+        if ((hmask + 1) < xfrm_policy_hashmax &&
+            cnt > hmask)
+                return 1;
+
+        return 0;
+}
+
+static inline int xfrm_byidx_should_resize(int total)
+{
+        unsigned int hmask = xfrm_idx_hmask;
+
+        if ((hmask + 1) < xfrm_policy_hashmax &&
+            total > hmask)
+                return 1;
+
+        return 0;
+}
+
+static DEFINE_MUTEX(hash_resize_mutex);
+
+static void xfrm_hash_resize(void *__unused)
+{
+        int dir, total;
+
+        mutex_lock(&hash_resize_mutex);
+
+        total = 0;
+        for (dir = 0; dir < XFRM_POLICY_MAX * 2; dir++) {
+                if (xfrm_bydst_should_resize(dir, &total))
+                        xfrm_bydst_resize(dir);
+        }
+        if (xfrm_byidx_should_resize(total))
+                xfrm_byidx_resize(total);
+
+        mutex_unlock(&hash_resize_mutex);
+}
+
+static DECLARE_WORK(xfrm_hash_work, xfrm_hash_resize, NULL);
+
 /* Generate new index... KAME seems to generate them ordered by cost
  * of an absolute inpredictability of ordering of rules. This will not pass. */
 static u32 xfrm_gen_index(u8 type, int dir)
 {
-        u32 idx;
-        struct xfrm_policy *p;
         static u32 idx_generator;
 
         for (;;) {
+                struct hlist_node *entry;
+                struct hlist_head *list;
+                struct xfrm_policy *p;
+                u32 idx;
+                int found;
+
                 idx = (idx_generator | dir);
                 idx_generator += 8;
                 if (idx == 0)
                         idx = 8;
-                for (p = XFRM_POLICY_LISTHEAD(type, dir); p; p = p->next) {
-                        if (p->index == idx)
+                list = xfrm_policy_byidx + idx_hash(idx);
+                found = 0;
+                hlist_for_each_entry(p, entry, list, byidx) {
+                        if (p->index == idx) {
+                                found = 1;
                                 break;
+                        }
                 }
-                if (!p)
+                if (!found)
                         return idx;
         }
 }
 
+static inline int selector_cmp(struct xfrm_selector *s1, struct xfrm_selector *s2)
+{
+        u32 *p1 = (u32 *) s1;
+        u32 *p2 = (u32 *) s2;
+        int len = sizeof(struct xfrm_selector) / sizeof(u32);
+        int i;
+
+        for (i = 0; i < len; i++) {
+                if (p1[i] != p2[i])
+                        return 1;
+        }
+
+        return 0;
+}
+
 int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
 {
-        struct xfrm_policy *pol, **p;
-        struct xfrm_policy *delpol = NULL;
-        struct xfrm_policy **newpos = NULL;
+        struct xfrm_policy *pol;
+        struct xfrm_policy *delpol;
+        struct hlist_head *chain;
+        struct hlist_node *entry, *newpos, *last;
         struct dst_entry *gc_list;
 
         write_lock_bh(&xfrm_policy_lock);
-        for (p = XFRM_POLICY_LISTHEADP(policy->type, dir); (pol=*p)!=NULL;) {
-                if (!delpol && memcmp(&policy->selector, &pol->selector, sizeof(pol->selector)) == 0 &&
+        chain = policy_hash_bysel(&policy->selector, policy->family, dir);
+        delpol = NULL;
+        newpos = NULL;
+        last = NULL;
+        hlist_for_each_entry(pol, entry, chain, bydst) {
+                if (!delpol &&
+                    pol->type == policy->type &&
+                    !selector_cmp(&pol->selector, &policy->selector) &&
                     xfrm_sec_ctx_match(pol->security, policy->security)) {
                         if (excl) {
                                 write_unlock_bh(&xfrm_policy_lock);
                                 return -EEXIST;
                         }
-                        *p = pol->next;
                         delpol = pol;
                         if (policy->priority > pol->priority)
                                 continue;
                 } else if (policy->priority >= pol->priority) {
-                        p = &pol->next;
+                        last = &pol->bydst;
                         continue;
                 }
                 if (!newpos)
-                        newpos = p;
+                        newpos = &pol->bydst;
                 if (delpol)
                         break;
-                p = &pol->next;
+                last = &pol->bydst;
         }
+        if (!newpos)
+                newpos = last;
         if (newpos)
-                p = newpos;
+                hlist_add_after(newpos, &policy->bydst);
+        else
+                hlist_add_head(&policy->bydst, chain);
         xfrm_pol_hold(policy);
-        policy->next = *p;
-        *p = policy;
+        xfrm_policy_count[dir]++;
         atomic_inc(&flow_cache_genid);
+        if (delpol) {
+                hlist_del(&delpol->bydst);
+                hlist_del(&delpol->byidx);
+                xfrm_policy_count[dir]--;
+        }
         policy->index = delpol ? delpol->index : xfrm_gen_index(policy->type, dir);
+        hlist_add_head(&policy->byidx, xfrm_policy_byidx+idx_hash(policy->index));
         policy->curlft.add_time = (unsigned long)xtime.tv_sec;
         policy->curlft.use_time = 0;
         if (!mod_timer(&policy->timer, jiffies + HZ))
@@ -479,10 +748,13 @@ int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
 
         if (delpol)
                 xfrm_policy_kill(delpol);
+        else if (xfrm_bydst_should_resize(dir, NULL))
+                schedule_work(&xfrm_hash_work);
 
         read_lock_bh(&xfrm_policy_lock);
         gc_list = NULL;
-        for (policy = policy->next; policy; policy = policy->next) {
+        entry = &policy->bydst;
+        hlist_for_each_entry_continue(policy, entry, bydst) {
                 struct dst_entry *dst;
 
                 write_lock(&policy->lock);
@@ -515,67 +787,112 @@ struct xfrm_policy *xfrm_policy_bysel_ctx(u8 type, int dir,
                                           struct xfrm_selector *sel,
                                           struct xfrm_sec_ctx *ctx, int delete)
 {
-        struct xfrm_policy *pol, **p;
+        struct xfrm_policy *pol, *ret;
+        struct hlist_head *chain;
+        struct hlist_node *entry;
 
         write_lock_bh(&xfrm_policy_lock);
-        for (p = XFRM_POLICY_LISTHEADP(type, dir); (pol=*p)!=NULL; p = &pol->next) {
-                if ((memcmp(sel, &pol->selector, sizeof(*sel)) == 0) &&
-                    (xfrm_sec_ctx_match(ctx, pol->security))) {
+        chain = policy_hash_bysel(sel, sel->family, dir);
+        ret = NULL;
+        hlist_for_each_entry(pol, entry, chain, bydst) {
+                if (pol->type == type &&
+                    !selector_cmp(sel, &pol->selector) &&
+                    xfrm_sec_ctx_match(ctx, pol->security)) {
                         xfrm_pol_hold(pol);
-                        if (delete)
-                                *p = pol->next;
+                        if (delete) {
+                                hlist_del(&pol->bydst);
+                                hlist_del(&pol->byidx);
+                                xfrm_policy_count[dir]--;
+                        }
+                        ret = pol;
                         break;
                 }
         }
         write_unlock_bh(&xfrm_policy_lock);
 
-        if (pol && delete) {
+        if (ret && delete) {
                 atomic_inc(&flow_cache_genid);
-                xfrm_policy_kill(pol);
+                xfrm_policy_kill(ret);
         }
-        return pol;
+        return ret;
 }
 EXPORT_SYMBOL(xfrm_policy_bysel_ctx);
 
 struct xfrm_policy *xfrm_policy_byid(u8 type, int dir, u32 id, int delete)
 {
-        struct xfrm_policy *pol, **p;
+        struct xfrm_policy *pol, *ret;
+        struct hlist_head *chain;
+        struct hlist_node *entry;
 
         write_lock_bh(&xfrm_policy_lock);
-        for (p = XFRM_POLICY_LISTHEADP(type, dir); (pol=*p)!=NULL; p = &pol->next) {
-                if (pol->index == id) {
+        chain = xfrm_policy_byidx + idx_hash(id);
+        ret = NULL;
+        hlist_for_each_entry(pol, entry, chain, byidx) {
+                if (pol->type == type && pol->index == id) {
                         xfrm_pol_hold(pol);
-                        if (delete)
-                                *p = pol->next;
+                        if (delete) {
+                                hlist_del(&pol->bydst);
+                                hlist_del(&pol->byidx);
+                                xfrm_policy_count[dir]--;
+                        }
+                        ret = pol;
                         break;
                 }
         }
         write_unlock_bh(&xfrm_policy_lock);
 
-        if (pol && delete) {
+        if (ret && delete) {
                 atomic_inc(&flow_cache_genid);
-                xfrm_policy_kill(pol);
+                xfrm_policy_kill(ret);
         }
-        return pol;
+        return ret;
 }
 EXPORT_SYMBOL(xfrm_policy_byid);
 
 void xfrm_policy_flush(u8 type)
 {
-        struct xfrm_policy *xp;
-        struct xfrm_policy **p_list = XFRM_POLICY_LISTS(type);
         int dir;
 
         write_lock_bh(&xfrm_policy_lock);
         for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
-                while ((xp = p_list[dir]) != NULL) {
-                        p_list[dir] = xp->next;
+                struct xfrm_policy *pol;
+                struct hlist_node *entry;
+                int i;
+
+        again1:
+                hlist_for_each_entry(pol, entry,
+                                     &xfrm_policy_inexact[dir], bydst) {
+                        if (pol->type != type)
+                                continue;
+                        hlist_del(&pol->bydst);
+                        hlist_del(&pol->byidx);
                         write_unlock_bh(&xfrm_policy_lock);
 
-                        xfrm_policy_kill(xp);
+                        xfrm_policy_kill(pol);
 
                         write_lock_bh(&xfrm_policy_lock);
+                        goto again1;
+                }
+
+                for (i = xfrm_policy_bydst[dir].hmask; i >= 0; i--) {
+        again2:
+                        hlist_for_each_entry(pol, entry,
+                                             xfrm_policy_bydst[dir].table + i,
+                                             bydst) {
+                                if (pol->type != type)
+                                        continue;
+                                hlist_del(&pol->bydst);
+                                hlist_del(&pol->byidx);
+                                write_unlock_bh(&xfrm_policy_lock);
+
+                                xfrm_policy_kill(pol);
+
+                                write_lock_bh(&xfrm_policy_lock);
+                                goto again2;
+                        }
                 }
+
+                xfrm_policy_count[dir] = 0;
         }
         atomic_inc(&flow_cache_genid);
         write_unlock_bh(&xfrm_policy_lock);
@@ -585,15 +902,27 @@ EXPORT_SYMBOL(xfrm_policy_flush);
 int xfrm_policy_walk(u8 type, int (*func)(struct xfrm_policy *, int, int, void*),
                      void *data)
 {
-        struct xfrm_policy *xp;
-        int dir;
-        int count = 0;
-        int error = 0;
+        struct xfrm_policy *pol;
+        struct hlist_node *entry;
+        int dir, count, error;
 
         read_lock_bh(&xfrm_policy_lock);
+        count = 0;
         for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
-                for (xp = XFRM_POLICY_LISTHEAD(type, dir); xp; xp = xp->next)
-                        count++;
+                struct hlist_head *table = xfrm_policy_bydst[dir].table;
+                int i;
+
+                hlist_for_each_entry(pol, entry,
+                                     &xfrm_policy_inexact[dir], bydst) {
+                        if (pol->type == type)
+                                count++;
+                }
+                for (i = xfrm_policy_bydst[dir].hmask; i >= 0; i--) {
+                        hlist_for_each_entry(pol, entry, table + i, bydst) {
+                                if (pol->type == type)
+                                        count++;
+                        }
+                }
         }
 
         if (count == 0) {
@@ -602,13 +931,28 @@ int xfrm_policy_walk(u8 type, int (*func)(struct xfrm_policy *, int, int, void*)
         }
 
         for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
-                for (xp = XFRM_POLICY_LISTHEAD(type, dir); xp; xp = xp->next) {
-                        error = func(xp, dir%XFRM_POLICY_MAX, --count, data);
+                struct hlist_head *table = xfrm_policy_bydst[dir].table;
+                int i;
+
+                hlist_for_each_entry(pol, entry,
+                                     &xfrm_policy_inexact[dir], bydst) {
+                        if (pol->type != type)
+                                continue;
+                        error = func(pol, dir % XFRM_POLICY_MAX, --count, data);
                         if (error)
                                 goto out;
                 }
+                for (i = xfrm_policy_bydst[dir].hmask; i >= 0; i--) {
+                        hlist_for_each_entry(pol, entry, table + i, bydst) {
+                                if (pol->type != type)
+                                        continue;
+                                error = func(pol, dir % XFRM_POLICY_MAX, --count, data);
+                                if (error)
+                                        goto out;
+                        }
+                }
         }
-
+        error = 0;
 out:
         read_unlock_bh(&xfrm_policy_lock);
         return error;
@@ -617,31 +961,61 @@ EXPORT_SYMBOL(xfrm_policy_walk);
 
 /* Find policy to apply to this flow. */
 
-static struct xfrm_policy *xfrm_policy_lookup_bytype(u8 type, struct flowi *fl,
-                                                     u16 family, u8 dir)
+static int xfrm_policy_match(struct xfrm_policy *pol, struct flowi *fl,
+                             u8 type, u16 family, int dir)
 {
-        struct xfrm_policy *pol;
+        struct xfrm_selector *sel = &pol->selector;
+        int match;
 
-        read_lock_bh(&xfrm_policy_lock);
-        for (pol = XFRM_POLICY_LISTHEAD(type, dir); pol; pol = pol->next) {
-                struct xfrm_selector *sel = &pol->selector;
-                int match;
+        if (pol->family != family ||
+            pol->type != type)
+                return 0;
 
-                if (pol->family != family)
-                        continue;
+        match = xfrm_selector_match(sel, fl, family);
+        if (match) {
+                if (!security_xfrm_policy_lookup(pol, fl->secid, dir))
+                        return 1;
+        }
+
+        return 0;
+}
 
-                match = xfrm_selector_match(sel, fl, family);
+static struct xfrm_policy *xfrm_policy_lookup_bytype(u8 type, struct flowi *fl,
+                                                     u16 family, u8 dir)
+{
+        struct xfrm_policy *pol, *ret;
+        xfrm_address_t *daddr, *saddr;
+        struct hlist_node *entry;
+        struct hlist_head *chain;
 
-                if (match) {
-                        if (!security_xfrm_policy_lookup(pol, fl->secid, dir)) {
+        daddr = xfrm_flowi_daddr(fl, family);
+        saddr = xfrm_flowi_saddr(fl, family);
+        if (unlikely(!daddr || !saddr))
+                return NULL;
+
+        read_lock_bh(&xfrm_policy_lock);
+        chain = policy_hash_direct(daddr, saddr, family, dir);
+        ret = NULL;
+        hlist_for_each_entry(pol, entry, chain, bydst) {
+                if (xfrm_policy_match(pol, fl, type, family, dir)) {
+                        xfrm_pol_hold(pol);
+                        ret = pol;
+                        break;
+                }
+        }
+        if (!ret) {
+                chain = &xfrm_policy_inexact[dir];
+                hlist_for_each_entry(pol, entry, chain, bydst) {
+                        if (xfrm_policy_match(pol, fl, type, family, dir)) {
                                 xfrm_pol_hold(pol);
+                                ret = pol;
                                 break;
                         }
                 }
         }
         read_unlock_bh(&xfrm_policy_lock);
 
-        return pol;
+        return ret;
 }
 
 static void xfrm_policy_lookup(struct flowi *fl, u16 family, u8 dir,
@@ -657,7 +1031,7 @@ static void xfrm_policy_lookup(struct flowi *fl, u16 family, u8 dir,
         pol = xfrm_policy_lookup_bytype(XFRM_POLICY_TYPE_MAIN, fl, family, dir);
 
 #ifdef CONFIG_XFRM_SUB_POLICY
- end:
+end:
 #endif
         if ((*objp = (void *) pol) != NULL)
                 *obj_refp = &pol->refcnt;
@@ -704,26 +1078,29 @@ static struct xfrm_policy *xfrm_sk_policy_lookup(struct sock *sk, int dir, struc
 
 static void __xfrm_policy_link(struct xfrm_policy *pol, int dir)
 {
-        struct xfrm_policy **p_list = XFRM_POLICY_LISTS(pol->type);
+        struct hlist_head *chain = policy_hash_bysel(&pol->selector,
+                                                     pol->family, dir);
 
-        pol->next = p_list[dir];
-        p_list[dir] = pol;
+        hlist_add_head(&pol->bydst, chain);
+        hlist_add_head(&pol->byidx, xfrm_policy_byidx+idx_hash(pol->index));
+        xfrm_policy_count[dir]++;
         xfrm_pol_hold(pol);
+
+        if (xfrm_bydst_should_resize(dir, NULL))
+                schedule_work(&xfrm_hash_work);
 }
 
 static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
                                                 int dir)
 {
-        struct xfrm_policy **polp;
+        if (hlist_unhashed(&pol->bydst))
+                return NULL;
 
-        for (polp = XFRM_POLICY_LISTHEADP(pol->type, dir);
-             *polp != NULL; polp = &(*polp)->next) {
-                if (*polp == pol) {
-                        *polp = pol->next;
-                        return pol;
-                }
-        }
-        return NULL;
+        hlist_del(&pol->bydst);
+        hlist_del(&pol->byidx);
+        xfrm_policy_count[dir]--;
+
+        return pol;
 }
 
 int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
@@ -968,7 +1345,8 @@ restart:
 
         if (!policy) {
                 /* To accelerate a bit...  */
-                if ((dst_orig->flags & DST_NOXFRM) || xfrm_policy_lists_empty(XFRM_POLICY_OUT))
+                if ((dst_orig->flags & DST_NOXFRM) ||
+                    !xfrm_policy_count[XFRM_POLICY_OUT])
                         return 0;
 
                 policy = flow_cache_lookup(fl, dst_orig->ops->family,
@@ -1413,50 +1791,50 @@ static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
         return dst;
 }
 
+static void prune_one_bundle(struct xfrm_policy *pol, int (*func)(struct dst_entry *), struct dst_entry **gc_list_p)
+{
+        struct dst_entry *dst, **dstp;
+
+        write_lock(&pol->lock);
+        dstp = &pol->bundles;
+        while ((dst=*dstp) != NULL) {
+                if (func(dst)) {
+                        *dstp = dst->next;
+                        dst->next = *gc_list_p;
+                        *gc_list_p = dst;
+                } else {
+                        dstp = &dst->next;
+                }
+        }
+        write_unlock(&pol->lock);
+}
+
 static void xfrm_prune_bundles(int (*func)(struct dst_entry *))
 {
-        int i;
-        struct xfrm_policy *pol;
-        struct dst_entry *dst, **dstp, *gc_list = NULL;
+        struct dst_entry *gc_list = NULL;
+        int dir;
 
         read_lock_bh(&xfrm_policy_lock);
-        for (i=0; i<2*XFRM_POLICY_MAX; i++) {
-#ifdef CONFIG_XFRM_SUB_POLICY
-                for (pol = xfrm_policy_list_sub[i]; pol; pol = pol->next) {
-                        write_lock(&pol->lock);
-                        dstp = &pol->bundles;
-                        while ((dst=*dstp) != NULL) {
-                                if (func(dst)) {
-                                        *dstp = dst->next;
-                                        dst->next = gc_list;
-                                        gc_list = dst;
-                                } else {
-                                        dstp = &dst->next;
-                                }
-                        }
-                        write_unlock(&pol->lock);
-                }
+        for (dir = 0; dir < XFRM_POLICY_MAX * 2; dir++) {
+                struct xfrm_policy *pol;
+                struct hlist_node *entry;
+                struct hlist_head *table;
+                int i;
 
-#endif
-                for (pol = xfrm_policy_list[i]; pol; pol = pol->next) {
-                        write_lock(&pol->lock);
-                        dstp = &pol->bundles;
-                        while ((dst=*dstp) != NULL) {
-                                if (func(dst)) {
-                                        *dstp = dst->next;
-                                        dst->next = gc_list;
-                                        gc_list = dst;
-                                } else {
-                                        dstp = &dst->next;
-                                }
-                        }
-                        write_unlock(&pol->lock);
+                hlist_for_each_entry(pol, entry,
+                                     &xfrm_policy_inexact[dir], bydst)
+                        prune_one_bundle(pol, func, &gc_list);
+
+                table = xfrm_policy_bydst[dir].table;
+                for (i = xfrm_policy_bydst[dir].hmask; i >= 0; i--) {
+                        hlist_for_each_entry(pol, entry, table + i, bydst)
+                                prune_one_bundle(pol, func, &gc_list);
                 }
         }
         read_unlock_bh(&xfrm_policy_lock);
 
         while (gc_list) {
-                dst = gc_list;
+                struct dst_entry *dst = gc_list;
                 gc_list = dst->next;
                 dst_free(dst);
         }
@@ -1680,6 +2058,9 @@ static struct notifier_block xfrm_dev_notifier = {
 
 static void __init xfrm_policy_init(void)
 {
+        unsigned int hmask, sz;
+        int dir;
+
         xfrm_dst_cache = kmem_cache_create("xfrm_dst_cache",
                                            sizeof(struct xfrm_dst),
                                            0, SLAB_HWCACHE_ALIGN,
@@ -1687,6 +2068,26 @@ static void __init xfrm_policy_init(void)
         if (!xfrm_dst_cache)
                 panic("XFRM: failed to allocate xfrm_dst_cache\n");
 
+        hmask = 8 - 1;
+        sz = (hmask+1) * sizeof(struct hlist_head);
+
+        xfrm_policy_byidx = xfrm_policy_hash_alloc(sz);
+        xfrm_idx_hmask = hmask;
+        if (!xfrm_policy_byidx)
+                panic("XFRM: failed to allocate byidx hash\n");
+
+        for (dir = 0; dir < XFRM_POLICY_MAX * 2; dir++) {
+                struct xfrm_policy_hash *htab;
+
+                INIT_HLIST_HEAD(&xfrm_policy_inexact[dir]);
+
+                htab = &xfrm_policy_bydst[dir];
+                htab->table = xfrm_policy_hash_alloc(sz);
+                htab->hmask = hmask;
+                if (!htab->table)
+                        panic("XFRM: failed to allocate bydst hash\n");
+        }
+
         INIT_WORK(&xfrm_policy_gc_work, xfrm_policy_gc_task, NULL);
         register_netdevice_notifier(&xfrm_dev_notifier);
 }