1 files changed, 132 insertions, 94 deletions

diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c
index dd9fc2523c76..ba96deacf27c 100644
--- a/net/sched/cls_route.c
+++ b/net/sched/cls_route.c
@@ -29,25 +29,26 @@
  *    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;