net: sched: RCU cls_route
[linux-2.6-microblaze.git] / net / sched / cls_route.c
index dd9fc25..ba96dea 100644 (file)
  *    are mutually  exclusive.
  * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
  */
-
 struct route4_fastmap {
-       struct route4_filter    *filter;
-       u32                     id;
-       int                     iif;
+       struct route4_filter            *filter;
+       u32                             id;
+       int                             iif;
 };
 
 struct route4_head {
-       struct route4_fastmap   fastmap[16];
-       struct route4_bucket    *table[256 + 1];
+       struct route4_fastmap           fastmap[16];
+       struct route4_bucket __rcu      *table[256 + 1];
+       struct rcu_head                 rcu;
 };
 
 struct route4_bucket {
        /* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
-       struct route4_filter    *ht[16 + 16 + 1];
+       struct route4_filter __rcu      *ht[16 + 16 + 1];
+       struct rcu_head                 rcu;
 };
 
 struct route4_filter {
-       struct route4_filter    *next;
+       struct route4_filter __rcu      *next;
        u32                     id;
        int                     iif;
 
@@ -55,6 +56,8 @@ struct route4_filter {
        struct tcf_exts         exts;
        u32                     handle;
        struct route4_bucket    *bkt;
+       struct tcf_proto        *tp;
+       struct rcu_head         rcu;
 };
 
 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
@@ -64,14 +67,13 @@ static inline int route4_fastmap_hash(u32 id, int iif)
        return id & 0xF;
 }
 
+static DEFINE_SPINLOCK(fastmap_lock);
 static void
-route4_reset_fastmap(struct Qdisc *q, struct route4_head *head, u32 id)
+route4_reset_fastmap(struct route4_head *head)
 {
-       spinlock_t *root_lock = qdisc_root_sleeping_lock(q);
-
-       spin_lock_bh(root_lock);
+       spin_lock_bh(&fastmap_lock);
        memset(head->fastmap, 0, sizeof(head->fastmap));
-       spin_unlock_bh(root_lock);
+       spin_unlock_bh(&fastmap_lock);
 }
 
 static void
@@ -80,9 +82,12 @@ route4_set_fastmap(struct route4_head *head, u32 id, int iif,
 {
        int h = route4_fastmap_hash(id, iif);
 
+       /* fastmap updates must look atomic to aling id, iff, filter */
+       spin_lock_bh(&fastmap_lock);
        head->fastmap[h].id = id;
        head->fastmap[h].iif = iif;
        head->fastmap[h].filter = f;
+       spin_unlock_bh(&fastmap_lock);
 }
 
 static inline int route4_hash_to(u32 id)
@@ -123,7 +128,7 @@ static inline int route4_hash_wild(void)
 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
                           struct tcf_result *res)
 {
-       struct route4_head *head = tp->root;
+       struct route4_head *head = rcu_dereference_bh(tp->root);
        struct dst_entry *dst;
        struct route4_bucket *b;
        struct route4_filter *f;
@@ -141,32 +146,43 @@ static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
        iif = inet_iif(skb);
 
        h = route4_fastmap_hash(id, iif);
+
+       spin_lock(&fastmap_lock);
        if (id == head->fastmap[h].id &&
            iif == head->fastmap[h].iif &&
            (f = head->fastmap[h].filter) != NULL) {
-               if (f == ROUTE4_FAILURE)
+               if (f == ROUTE4_FAILURE) {
+                       spin_unlock(&fastmap_lock);
                        goto failure;
+               }
 
                *res = f->res;
+               spin_unlock(&fastmap_lock);
                return 0;
        }
+       spin_unlock(&fastmap_lock);
 
        h = route4_hash_to(id);
 
 restart:
-       b = head->table[h];
+       b = rcu_dereference_bh(head->table[h]);
        if (b) {
-               for (f = b->ht[route4_hash_from(id)]; f; f = f->next)
+               for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
+                    f;
+                    f = rcu_dereference_bh(f->next))
                        if (f->id == id)
                                ROUTE4_APPLY_RESULT();
 
-               for (f = b->ht[route4_hash_iif(iif)]; f; f = f->next)
+               for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
+                    f;
+                    f = rcu_dereference_bh(f->next))
                        if (f->iif == iif)
                                ROUTE4_APPLY_RESULT();
 
-               for (f = b->ht[route4_hash_wild()]; f; f = f->next)
+               for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
+                    f;
+                    f = rcu_dereference_bh(f->next))
                        ROUTE4_APPLY_RESULT();
-
        }
        if (h < 256) {
                h = 256;
@@ -213,7 +229,7 @@ static inline u32 from_hash(u32 id)
 
 static unsigned long route4_get(struct tcf_proto *tp, u32 handle)
 {
-       struct route4_head *head = tp->root;
+       struct route4_head *head = rtnl_dereference(tp->root);
        struct route4_bucket *b;
        struct route4_filter *f;
        unsigned int h1, h2;
@@ -229,9 +245,11 @@ static unsigned long route4_get(struct tcf_proto *tp, u32 handle)
        if (h2 > 32)
                return 0;
 
-       b = head->table[h1];
+       b = rtnl_dereference(head->table[h1]);
        if (b) {
-               for (f = b->ht[h2]; f; f = f->next)
+               for (f = rtnl_dereference(b->ht[h2]);
+                    f;
+                    f = rtnl_dereference(f->next))
                        if (f->handle == handle)
                                return (unsigned long)f;
        }
@@ -248,8 +266,11 @@ static int route4_init(struct tcf_proto *tp)
 }
 
 static void
-route4_delete_filter(struct tcf_proto *tp, struct route4_filter *f)
+route4_delete_filter(struct rcu_head *head)
 {
+       struct route4_filter *f = container_of(head, struct route4_filter, rcu);
+       struct tcf_proto *tp = f->tp;
+
        tcf_unbind_filter(tp, &f->res);
        tcf_exts_destroy(tp, &f->exts);
        kfree(f);
@@ -257,7 +278,7 @@ route4_delete_filter(struct tcf_proto *tp, struct route4_filter *f)
 
 static void route4_destroy(struct tcf_proto *tp)
 {
-       struct route4_head *head = tp->root;
+       struct route4_head *head = rtnl_dereference(tp->root);
        int h1, h2;
 
        if (head == NULL)
@@ -266,28 +287,35 @@ static void route4_destroy(struct tcf_proto *tp)
        for (h1 = 0; h1 <= 256; h1++) {
                struct route4_bucket *b;
 
-               b = head->table[h1];
+               b = rtnl_dereference(head->table[h1]);
                if (b) {
                        for (h2 = 0; h2 <= 32; h2++) {
                                struct route4_filter *f;
 
-                               while ((f = b->ht[h2]) != NULL) {
-                                       b->ht[h2] = f->next;
-                                       route4_delete_filter(tp, f);
+                               while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
+                                       struct route4_filter *next;
+
+                                       next = rtnl_dereference(f->next);
+                                       RCU_INIT_POINTER(b->ht[h2], next);
+                                       call_rcu(&f->rcu, route4_delete_filter);
                                }
                        }
-                       kfree(b);
+                       RCU_INIT_POINTER(head->table[h1], NULL);
+                       kfree_rcu(b, rcu);
                }
        }
-       kfree(head);
+       RCU_INIT_POINTER(tp->root, NULL);
+       kfree_rcu(head, rcu);
 }
 
 static int route4_delete(struct tcf_proto *tp, unsigned long arg)
 {
-       struct route4_head *head = tp->root;
-       struct route4_filter **fp, *f = (struct route4_filter *)arg;
-       unsigned int h = 0;
+       struct route4_head *head = rtnl_dereference(tp->root);
+       struct route4_filter *f = (struct route4_filter *)arg;
+       struct route4_filter __rcu **fp;
+       struct route4_filter *nf;
        struct route4_bucket *b;
+       unsigned int h = 0;
        int i;
 
        if (!head || !f)
@@ -296,27 +324,35 @@ static int route4_delete(struct tcf_proto *tp, unsigned long arg)
        h = f->handle;
        b = f->bkt;
 
-       for (fp = &b->ht[from_hash(h >> 16)]; *fp; fp = &(*fp)->next) {
-               if (*fp == f) {
-                       tcf_tree_lock(tp);
-                       *fp = f->next;
-                       tcf_tree_unlock(tp);
+       fp = &b->ht[from_hash(h >> 16)];
+       for (nf = rtnl_dereference(*fp); nf;
+            fp = &nf->next, nf = rtnl_dereference(*fp)) {
+               if (nf == f) {
+                       /* unlink it */
+                       RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 
-                       route4_reset_fastmap(tp->q, head, f->id);
-                       route4_delete_filter(tp, f);
+                       /* Remove any fastmap lookups that might ref filter
+                        * notice we unlink'd the filter so we can't get it
+                        * back in the fastmap.
+                        */
+                       route4_reset_fastmap(head);
 
-                       /* Strip tree */
+                       /* Delete it */
+                       call_rcu(&f->rcu, route4_delete_filter);
 
-                       for (i = 0; i <= 32; i++)
-                               if (b->ht[i])
+                       /* Strip RTNL protected tree */
+                       for (i = 0; i <= 32; i++) {
+                               struct route4_filter *rt;
+
+                               rt = rtnl_dereference(b->ht[i]);
+                               if (rt)
                                        return 0;
+                       }
 
                        /* OK, session has no flows */
-                       tcf_tree_lock(tp);
-                       head->table[to_hash(h)] = NULL;
-                       tcf_tree_unlock(tp);
+                       RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
+                       kfree_rcu(b, rcu);
 
-                       kfree(b);
                        return 0;
                }
        }
@@ -380,26 +416,25 @@ static int route4_set_parms(struct net *net, struct tcf_proto *tp,
        }
 
        h1 = to_hash(nhandle);
-       b = head->table[h1];
+       b = rtnl_dereference(head->table[h1]);
        if (!b) {
                err = -ENOBUFS;
                b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
                if (b == NULL)
                        goto errout;
 
-               tcf_tree_lock(tp);
-               head->table[h1] = b;
-               tcf_tree_unlock(tp);
+               rcu_assign_pointer(head->table[h1], b);
        } else {
                unsigned int h2 = from_hash(nhandle >> 16);
 
                err = -EEXIST;
-               for (fp = b->ht[h2]; fp; fp = fp->next)
+               for (fp = rtnl_dereference(b->ht[h2]);
+                    fp;
+                    fp = rtnl_dereference(fp->next))
                        if (fp->handle == f->handle)
                                goto errout;
        }
 
-       tcf_tree_lock(tp);
        if (tb[TCA_ROUTE4_TO])
                f->id = to;
 
@@ -410,7 +445,7 @@ static int route4_set_parms(struct net *net, struct tcf_proto *tp,
 
        f->handle = nhandle;
        f->bkt = b;
-       tcf_tree_unlock(tp);
+       f->tp = tp;
 
        if (tb[TCA_ROUTE4_CLASSID]) {
                f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
@@ -431,14 +466,15 @@ static int route4_change(struct net *net, struct sk_buff *in_skb,
                       struct nlattr **tca,
                       unsigned long *arg, bool ovr)
 {
-       struct route4_head *head = tp->root;
-       struct route4_filter *f, *f1, **fp;
+       struct route4_head *head = rtnl_dereference(tp->root);
+       struct route4_filter __rcu **fp;
+       struct route4_filter *fold, *f1, *pfp, *f = NULL;
        struct route4_bucket *b;
        struct nlattr *opt = tca[TCA_OPTIONS];
        struct nlattr *tb[TCA_ROUTE4_MAX + 1];
        unsigned int h, th;
-       u32 old_handle = 0;
        int err;
+       bool new = true;
 
        if (opt == NULL)
                return handle ? -EINVAL : 0;
@@ -447,70 +483,70 @@ static int route4_change(struct net *net, struct sk_buff *in_skb,
        if (err < 0)
                return err;
 
-       f = (struct route4_filter *)*arg;
-       if (f) {
-               if (f->handle != handle && handle)
+       fold = (struct route4_filter *)*arg;
+       if (fold && handle && fold->handle != handle)
                        return -EINVAL;
 
-               if (f->bkt)
-                       old_handle = f->handle;
-
-               err = route4_set_parms(net, tp, base, f, handle, head, tb,
-                       tca[TCA_RATE], 0, ovr);
-               if (err < 0)
-                       return err;
-
-               goto reinsert;
-       }
-
        err = -ENOBUFS;
        if (head == NULL) {
                head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
                if (head == NULL)
                        goto errout;
-
-               tcf_tree_lock(tp);
-               tp->root = head;
-               tcf_tree_unlock(tp);
+               rcu_assign_pointer(tp->root, head);
        }
 
        f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
-       if (f == NULL)
+       if (!f)
                goto errout;
 
        tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
+       if (fold) {
+               f->id = fold->id;
+               f->iif = fold->iif;
+               f->res = fold->res;
+               f->handle = fold->handle;
+
+               f->tp = fold->tp;
+               f->bkt = fold->bkt;
+               new = false;
+       }
+
        err = route4_set_parms(net, tp, base, f, handle, head, tb,
-               tca[TCA_RATE], 1, ovr);
+                              tca[TCA_RATE], new, ovr);
        if (err < 0)
                goto errout;
 
-reinsert:
        h = from_hash(f->handle >> 16);
-       for (fp = &f->bkt->ht[h]; (f1 = *fp) != NULL; fp = &f1->next)
+       fp = &f->bkt->ht[h];
+       for (pfp = rtnl_dereference(*fp);
+            (f1 = rtnl_dereference(*fp)) != NULL;
+            fp = &f1->next)
                if (f->handle < f1->handle)
                        break;
 
-       f->next = f1;
-       tcf_tree_lock(tp);
-       *fp = f;
+       rcu_assign_pointer(f->next, f1);
+       rcu_assign_pointer(*fp, f);
 
-       if (old_handle && f->handle != old_handle) {
-               th = to_hash(old_handle);
-               h = from_hash(old_handle >> 16);
-               b = head->table[th];
+       if (fold && fold->handle && f->handle != fold->handle) {
+               th = to_hash(fold->handle);
+               h = from_hash(fold->handle >> 16);
+               b = rtnl_dereference(head->table[th]);
                if (b) {
-                       for (fp = &b->ht[h]; *fp; fp = &(*fp)->next) {
-                               if (*fp == f) {
+                       fp = &b->ht[h];
+                       for (pfp = rtnl_dereference(*fp); pfp;
+                            fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
+                               if (pfp == f) {
                                        *fp = f->next;
                                        break;
                                }
                        }
                }
        }
-       tcf_tree_unlock(tp);
 
-       route4_reset_fastmap(tp->q, head, f->id);
+       route4_reset_fastmap(head);
        *arg = (unsigned long)f;
+       if (fold)
+               call_rcu(&fold->rcu, route4_delete_filter);
        return 0;
 
 errout:
@@ -520,7 +556,7 @@ errout:
 
 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 {
-       struct route4_head *head = tp->root;
+       struct route4_head *head = rtnl_dereference(tp->root);
        unsigned int h, h1;
 
        if (head == NULL)
@@ -530,13 +566,15 @@ static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
                return;
 
        for (h = 0; h <= 256; h++) {
-               struct route4_bucket *b = head->table[h];
+               struct route4_bucket *b = rtnl_dereference(head->table[h]);
 
                if (b) {
                        for (h1 = 0; h1 <= 32; h1++) {
                                struct route4_filter *f;
 
-                               for (f = b->ht[h1]; f; f = f->next) {
+                               for (f = rtnl_dereference(b->ht[h1]);
+                                    f;
+                                    f = rtnl_dereference(f->next)) {
                                        if (arg->count < arg->skip) {
                                                arg->count++;
                                                continue;