From bb047ddd145860ff24820320a21f03cf8c071b22 Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Tue, 13 Feb 2018 12:00:16 +0100 Subject: [PATCH 1/2] net: sched: don't set q pointer for shared blocks It is pointless to set block->q for block which are shared among multiple qdiscs. So remove the assignment in that case. Do a bit of code reshuffle to make block->index initialized at that point so we can use tcf_block_shared() helper. Reported-by: Cong Wang Fixes: 4861738775d7 ("net: sched: introduce shared filter blocks infrastructure") Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller --- net/sched/cls_api.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 2bc1bc23d42ec..a7dc7271042a2 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -376,17 +376,12 @@ struct tcf_net { static unsigned int tcf_net_id; static int tcf_block_insert(struct tcf_block *block, struct net *net, - u32 block_index, struct netlink_ext_ack *extack) + struct netlink_ext_ack *extack) { struct tcf_net *tn = net_generic(net, tcf_net_id); - int err; - err = idr_alloc_u32(&tn->idr, block, &block_index, block_index, - GFP_KERNEL); - if (err) - return err; - block->index = block_index; - return 0; + return idr_alloc_u32(&tn->idr, block, &block->index, block->index, + GFP_KERNEL); } static void tcf_block_remove(struct tcf_block *block, struct net *net) @@ -397,6 +392,7 @@ static void tcf_block_remove(struct tcf_block *block, struct net *net) } static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q, + u32 block_index, struct netlink_ext_ack *extack) { struct tcf_block *block; @@ -419,10 +415,13 @@ static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q, err = -ENOMEM; goto err_chain_create; } - block->net = qdisc_net(q); block->refcnt = 1; block->net = net; - block->q = q; + block->index = block_index; + + /* Don't store q pointer for blocks which are shared */ + if (!tcf_block_shared(block)) + block->q = q; return block; err_chain_create: @@ -518,13 +517,12 @@ int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q, } if (!block) { - block = tcf_block_create(net, q, extack); + block = tcf_block_create(net, q, ei->block_index, extack); if (IS_ERR(block)) return PTR_ERR(block); created = true; - if (ei->block_index) { - err = tcf_block_insert(block, net, - ei->block_index, extack); + if (tcf_block_shared(block)) { + err = tcf_block_insert(block, net, extack); if (err) goto err_block_insert; } From 339c21d7c459238135d87da8fefbfd25d98bc375 Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Tue, 13 Feb 2018 12:00:17 +0100 Subject: [PATCH 2/2] net: sched: fix tc_u_common lookup MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The offending commit wrongly assumes 1:1 mapping between block and q. However, there are multiple blocks for a single q for classful qdiscs. Since the obscure tc_u_common sharing mechanism expects it to be shared among a qdisc, fix it by storing q pointer in case the block is not shared. Reported-by: Paweł Staszewski Reported-by: Cong Wang Fixes: 7fa9d974f3c2 ("net: sched: cls_u32: use block instead of q in tc_u_common") Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller --- net/sched/cls_u32.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 6c7601a530e35..ed8b6a24b9e93 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -96,7 +96,7 @@ struct tc_u_hnode { struct tc_u_common { struct tc_u_hnode __rcu *hlist; - struct tcf_block *block; + void *ptr; int refcnt; struct idr handle_idr; struct hlist_node hnode; @@ -330,9 +330,25 @@ static struct hlist_head *tc_u_common_hash; #define U32_HASH_SHIFT 10 #define U32_HASH_SIZE (1 << U32_HASH_SHIFT) +static void *tc_u_common_ptr(const struct tcf_proto *tp) +{ + struct tcf_block *block = tp->chain->block; + + /* The block sharing is currently supported only + * for classless qdiscs. In that case we use block + * for tc_u_common identification. In case the + * block is not shared, block->q is a valid pointer + * and we can use that. That works for classful qdiscs. + */ + if (tcf_block_shared(block)) + return block; + else + return block->q; +} + static unsigned int tc_u_hash(const struct tcf_proto *tp) { - return hash_ptr(tp->chain->block, U32_HASH_SHIFT); + return hash_ptr(tc_u_common_ptr(tp), U32_HASH_SHIFT); } static struct tc_u_common *tc_u_common_find(const struct tcf_proto *tp) @@ -342,7 +358,7 @@ static struct tc_u_common *tc_u_common_find(const struct tcf_proto *tp) h = tc_u_hash(tp); hlist_for_each_entry(tc, &tc_u_common_hash[h], hnode) { - if (tc->block == tp->chain->block) + if (tc->ptr == tc_u_common_ptr(tp)) return tc; } return NULL; @@ -371,7 +387,7 @@ static int u32_init(struct tcf_proto *tp) kfree(root_ht); return -ENOBUFS; } - tp_c->block = tp->chain->block; + tp_c->ptr = tc_u_common_ptr(tp); INIT_HLIST_NODE(&tp_c->hnode); idr_init(&tp_c->handle_idr);