Merge branch 'sched-fixes'

Victor Nogueira says:

====================
net: sched: Fixes for classifiers

Four different classifiers (bpf, u32, matchall, and flower) are
calling tcf_bind_filter in their callbacks, but arent't undoing it by
calling tcf_unbind_filter if their was an error after binding.

This patch set fixes all this by calling tcf_unbind_filter in such
cases.

This set also undoes a refcount decrement in cls_u32 when an update
fails under specific conditions which are described in patch #3.

v1 -> v2:
* Remove blank line after fixes tag
* Fix reverse xmas tree issues pointed out by Simon

v2 -> v3:
* Inline functions cls_bpf_set_parms and fl_set_parms to avoid adding
  yet another parameter (and a return value at it) to them.
* Remove similar fixes for u32 and matchall, which will be sent soon,
  once we find a way to do the fixes without adding a return parameter
  to their set_parms functions.

v3 -> v4:
* Inline mall_set_parms to avoid adding yet another parameter.
* Remove set_flags parameter from u32_set_parms and create a separate
  function for calling tcf_bind_filter and tcf_unbind_filter in case of
  failure.
* Change cover letter title to also encompass refcnt fix for u32

v4 -> v5:
* Change back tag to net
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/cls_bpf.c

@@ -406,56 +406,6 @@ static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 	return 0;
 }
 
-static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
-			     struct cls_bpf_prog *prog, unsigned long base,
-			     struct nlattr **tb, struct nlattr *est, u32 flags,
-			     struct netlink_ext_ack *extack)
-{
-	bool is_bpf, is_ebpf, have_exts = false;
-	u32 gen_flags = 0;
-	int ret;
-
-	is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
-	is_ebpf = tb[TCA_BPF_FD];
-	if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
-		return -EINVAL;
-
-	ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, flags,
-				extack);
-	if (ret < 0)
-		return ret;
-
-	if (tb[TCA_BPF_FLAGS]) {
-		u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
-
-		if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
-			return -EINVAL;
-
-		have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
-	}
-	if (tb[TCA_BPF_FLAGS_GEN]) {
-		gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
-		if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
-		    !tc_flags_valid(gen_flags))
-			return -EINVAL;
-	}
-
-	prog->exts_integrated = have_exts;
-	prog->gen_flags = gen_flags;
-
-	ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
-		       cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
-	if (ret < 0)
-		return ret;
-
-	if (tb[TCA_BPF_CLASSID]) {
-		prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
-		tcf_bind_filter(tp, &prog->res, base);
-	}
-
-	return 0;
-}
-
 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 			  struct tcf_proto *tp, unsigned long base,
 			  u32 handle, struct nlattr **tca,
@@ -463,9 +413,12 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 			  struct netlink_ext_ack *extack)
 {
 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
+	bool is_bpf, is_ebpf, have_exts = false;
 	struct cls_bpf_prog *oldprog = *arg;
 	struct nlattr *tb[TCA_BPF_MAX + 1];
+	bool bound_to_filter = false;
 	struct cls_bpf_prog *prog;
+	u32 gen_flags = 0;
 	int ret;
 
 	if (tca[TCA_OPTIONS] == NULL)
@@ -504,11 +457,51 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 		goto errout;
 	prog->handle = handle;
 
-	ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], flags,
-				extack);
+	is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
+	is_ebpf = tb[TCA_BPF_FD];
+	if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) {
+		ret = -EINVAL;
+		goto errout_idr;
+	}
+
+	ret = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &prog->exts,
+				flags, extack);
+	if (ret < 0)
+		goto errout_idr;
+
+	if (tb[TCA_BPF_FLAGS]) {
+		u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
+
+		if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) {
+			ret = -EINVAL;
+			goto errout_idr;
+		}
+
+		have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
+	}
+	if (tb[TCA_BPF_FLAGS_GEN]) {
+		gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
+		if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
+		    !tc_flags_valid(gen_flags)) {
+			ret = -EINVAL;
+			goto errout_idr;
+		}
+	}
+
+	prog->exts_integrated = have_exts;
+	prog->gen_flags = gen_flags;
+
+	ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
+		cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
 	if (ret < 0)
 		goto errout_idr;
 
+	if (tb[TCA_BPF_CLASSID]) {
+		prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
+		tcf_bind_filter(tp, &prog->res, base);
+		bound_to_filter = true;
+	}
+
 	ret = cls_bpf_offload(tp, prog, oldprog, extack);
 	if (ret)
 		goto errout_parms;
@@ -530,6 +523,8 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 	return 0;
 
 errout_parms:
+	if (bound_to_filter)
+		tcf_unbind_filter(tp, &prog->res);
 	cls_bpf_free_parms(prog);
 errout_idr:
 	if (!oldprog)

net/sched/cls_flower.c

@@ -2173,53 +2173,6 @@ static bool fl_needs_tc_skb_ext(const struct fl_flow_key *mask)
 	return mask->meta.l2_miss;
 }
 
-static int fl_set_parms(struct net *net, struct tcf_proto *tp,
-			struct cls_fl_filter *f, struct fl_flow_mask *mask,
-			unsigned long base, struct nlattr **tb,
-			struct nlattr *est,
-			struct fl_flow_tmplt *tmplt,
-			u32 flags, u32 fl_flags,
-			struct netlink_ext_ack *extack)
-{
-	int err;
-
-	err = tcf_exts_validate_ex(net, tp, tb, est, &f->exts, flags,
-				   fl_flags, extack);
-	if (err < 0)
-		return err;
-
-	if (tb[TCA_FLOWER_CLASSID]) {
-		f->res.classid = nla_get_u32(tb[TCA_FLOWER_CLASSID]);
-		if (flags & TCA_ACT_FLAGS_NO_RTNL)
-			rtnl_lock();
-		tcf_bind_filter(tp, &f->res, base);
-		if (flags & TCA_ACT_FLAGS_NO_RTNL)
-			rtnl_unlock();
-	}
-
-	err = fl_set_key(net, tb, &f->key, &mask->key, extack);
-	if (err)
-		return err;
-
-	fl_mask_update_range(mask);
-	fl_set_masked_key(&f->mkey, &f->key, mask);
-
-	if (!fl_mask_fits_tmplt(tmplt, mask)) {
-		NL_SET_ERR_MSG_MOD(extack, "Mask does not fit the template");
-		return -EINVAL;
-	}
-
-	/* Enable tc skb extension if filter matches on data extracted from
-	 * this extension.
-	 */
-	if (fl_needs_tc_skb_ext(&mask->key)) {
-		f->needs_tc_skb_ext = 1;
-		tc_skb_ext_tc_enable();
-	}
-
-	return 0;
-}
-
 static int fl_ht_insert_unique(struct cls_fl_filter *fnew,
 			       struct cls_fl_filter *fold,
 			       bool *in_ht)
@@ -2251,6 +2204,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 	struct cls_fl_head *head = fl_head_dereference(tp);
 	bool rtnl_held = !(flags & TCA_ACT_FLAGS_NO_RTNL);
 	struct cls_fl_filter *fold = *arg;
+	bool bound_to_filter = false;
 	struct cls_fl_filter *fnew;
 	struct fl_flow_mask *mask;
 	struct nlattr **tb;
@@ -2335,15 +2289,46 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 	if (err < 0)
 		goto errout_idr;
 
-	err = fl_set_parms(net, tp, fnew, mask, base, tb, tca[TCA_RATE],
-			   tp->chain->tmplt_priv, flags, fnew->flags,
-			   extack);
-	if (err)
+	err = tcf_exts_validate_ex(net, tp, tb, tca[TCA_RATE],
+				   &fnew->exts, flags, fnew->flags,
+				   extack);
+	if (err < 0)
 		goto errout_idr;
 
+	if (tb[TCA_FLOWER_CLASSID]) {
+		fnew->res.classid = nla_get_u32(tb[TCA_FLOWER_CLASSID]);
+		if (flags & TCA_ACT_FLAGS_NO_RTNL)
+			rtnl_lock();
+		tcf_bind_filter(tp, &fnew->res, base);
+		if (flags & TCA_ACT_FLAGS_NO_RTNL)
+			rtnl_unlock();
+		bound_to_filter = true;
+	}
+
+	err = fl_set_key(net, tb, &fnew->key, &mask->key, extack);
+	if (err)
+		goto unbind_filter;
+
+	fl_mask_update_range(mask);
+	fl_set_masked_key(&fnew->mkey, &fnew->key, mask);
+
+	if (!fl_mask_fits_tmplt(tp->chain->tmplt_priv, mask)) {
+		NL_SET_ERR_MSG_MOD(extack, "Mask does not fit the template");
+		err = -EINVAL;
+		goto unbind_filter;
+	}
+
+	/* Enable tc skb extension if filter matches on data extracted from
+	 * this extension.
+	 */
+	if (fl_needs_tc_skb_ext(&mask->key)) {
+		fnew->needs_tc_skb_ext = 1;
+		tc_skb_ext_tc_enable();
+	}
+
 	err = fl_check_assign_mask(head, fnew, fold, mask);
 	if (err)
-		goto errout_idr;
+		goto unbind_filter;
 
 	err = fl_ht_insert_unique(fnew, fold, &in_ht);
 	if (err)
@@ -2434,6 +2419,16 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 				       fnew->mask->filter_ht_params);
 errout_mask:
 	fl_mask_put(head, fnew->mask);
+
+unbind_filter:
+	if (bound_to_filter) {
+		if (flags & TCA_ACT_FLAGS_NO_RTNL)
+			rtnl_lock();
+		tcf_unbind_filter(tp, &fnew->res);
+		if (flags & TCA_ACT_FLAGS_NO_RTNL)
+			rtnl_unlock();
+	}
+
 errout_idr:
 	if (!fold)
 		idr_remove(&head->handle_idr, fnew->handle);

net/sched/cls_matchall.c

@@ -159,26 +159,6 @@ static const struct nla_policy mall_policy[TCA_MATCHALL_MAX + 1] = {
 	[TCA_MATCHALL_FLAGS]		= { .type = NLA_U32 },
 };
 
-static int mall_set_parms(struct net *net, struct tcf_proto *tp,
-			  struct cls_mall_head *head,
-			  unsigned long base, struct nlattr **tb,
-			  struct nlattr *est, u32 flags, u32 fl_flags,
-			  struct netlink_ext_ack *extack)
-{
-	int err;
-
-	err = tcf_exts_validate_ex(net, tp, tb, est, &head->exts, flags,
-				   fl_flags, extack);
-	if (err < 0)
-		return err;
-
-	if (tb[TCA_MATCHALL_CLASSID]) {
-		head->res.classid = nla_get_u32(tb[TCA_MATCHALL_CLASSID]);
-		tcf_bind_filter(tp, &head->res, base);
-	}
-	return 0;
-}
-
 static int mall_change(struct net *net, struct sk_buff *in_skb,
 		       struct tcf_proto *tp, unsigned long base,
 		       u32 handle, struct nlattr **tca,
@@ -187,6 +167,7 @@ static int mall_change(struct net *net, struct sk_buff *in_skb,
 {
 	struct cls_mall_head *head = rtnl_dereference(tp->root);
 	struct nlattr *tb[TCA_MATCHALL_MAX + 1];
+	bool bound_to_filter = false;
 	struct cls_mall_head *new;
 	u32 userflags = 0;
 	int err;
@@ -226,11 +207,17 @@ static int mall_change(struct net *net, struct sk_buff *in_skb,
 		goto err_alloc_percpu;
 	}
 
-	err = mall_set_parms(net, tp, new, base, tb, tca[TCA_RATE],
-			     flags, new->flags, extack);
-	if (err)
+	err = tcf_exts_validate_ex(net, tp, tb, tca[TCA_RATE],
+				   &new->exts, flags, new->flags, extack);
+	if (err < 0)
 		goto err_set_parms;
 
+	if (tb[TCA_MATCHALL_CLASSID]) {
+		new->res.classid = nla_get_u32(tb[TCA_MATCHALL_CLASSID]);
+		tcf_bind_filter(tp, &new->res, base);
+		bound_to_filter = true;
+	}
+
 	if (!tc_skip_hw(new->flags)) {
 		err = mall_replace_hw_filter(tp, new, (unsigned long)new,
 					     extack);
@@ -246,6 +233,8 @@ static int mall_change(struct net *net, struct sk_buff *in_skb,
 	return 0;
 
 err_replace_hw_filter:
+	if (bound_to_filter)
+		tcf_unbind_filter(tp, &new->res);
 err_set_parms:
 	free_percpu(new->pf);
 err_alloc_percpu:

net/sched/cls_u32.c

@@ -712,8 +712,23 @@ static const struct nla_policy u32_policy[TCA_U32_MAX + 1] = {
 	[TCA_U32_FLAGS]		= { .type = NLA_U32 },
 };
 
+static void u32_unbind_filter(struct tcf_proto *tp, struct tc_u_knode *n,
+			      struct nlattr **tb)
+{
+	if (tb[TCA_U32_CLASSID])
+		tcf_unbind_filter(tp, &n->res);
+}
+
+static void u32_bind_filter(struct tcf_proto *tp, struct tc_u_knode *n,
+			    unsigned long base, struct nlattr **tb)
+{
+	if (tb[TCA_U32_CLASSID]) {
+		n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
+		tcf_bind_filter(tp, &n->res, base);
+	}
+}
+
 static int u32_set_parms(struct net *net, struct tcf_proto *tp,
-			 unsigned long base,
 			 struct tc_u_knode *n, struct nlattr **tb,
 			 struct nlattr *est, u32 flags, u32 fl_flags,
 			 struct netlink_ext_ack *extack)
@@ -760,10 +775,6 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
 		if (ht_old)
 			ht_old->refcnt--;
 	}
-	if (tb[TCA_U32_CLASSID]) {
-		n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
-		tcf_bind_filter(tp, &n->res, base);
-	}
 
 	if (ifindex >= 0)
 		n->ifindex = ifindex;
@@ -903,17 +914,27 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		if (!new)
 			return -ENOMEM;
 
-		err = u32_set_parms(net, tp, base, new, tb,
-				    tca[TCA_RATE], flags, new->flags,
-				    extack);
+		err = u32_set_parms(net, tp, new, tb, tca[TCA_RATE],
+				    flags, new->flags, extack);
 
 		if (err) {
 			__u32_destroy_key(new);
 			return err;
 		}
 
+		u32_bind_filter(tp, new, base, tb);
+
 		err = u32_replace_hw_knode(tp, new, flags, extack);
 		if (err) {
+			u32_unbind_filter(tp, new, tb);
+
+			if (tb[TCA_U32_LINK]) {
+				struct tc_u_hnode *ht_old;
+
+				ht_old = rtnl_dereference(n->ht_down);
+				if (ht_old)
+					ht_old->refcnt++;
+			}
 			__u32_destroy_key(new);
 			return err;
 		}
@@ -1074,15 +1095,18 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 	}
 #endif
 
-	err = u32_set_parms(net, tp, base, n, tb, tca[TCA_RATE],
+	err = u32_set_parms(net, tp, n, tb, tca[TCA_RATE],
 			    flags, n->flags, extack);
+
+	u32_bind_filter(tp, n, base, tb);
+
 	if (err == 0) {
 		struct tc_u_knode __rcu **ins;
 		struct tc_u_knode *pins;
 
 		err = u32_replace_hw_knode(tp, n, flags, extack);
 		if (err)
-			goto errhw;
+			goto errunbind;
 
 		if (!tc_in_hw(n->flags))
 			n->flags |= TCA_CLS_FLAGS_NOT_IN_HW;
@@ -1100,7 +1124,9 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		return 0;
 	}
 
-errhw:
+errunbind:
+	u32_unbind_filter(tp, n, tb);
+
 #ifdef CONFIG_CLS_U32_MARK
 	free_percpu(n->pcpu_success);
 #endif