From: Jiri Pirko <jiri@mellanox.com>
Date: Tue, 13 Feb 2018 12:00:17 +0100
Subject: net: sched: fix tc_u_common lookup
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Patch-mainline: v4.16-rc3
Git-commit: 339c21d7c459238135d87da8fefbfd25d98bc375
References: bsc#1109837
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 <pstaszewski@itcare.pl>
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Fixes: 7fa9d974f3c2 ("net: sched: cls_u32: use block instead of q in tc_u_common")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/sched/cls_u32.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -97,7 +97,7 @@ 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;
@@ -331,9 +331,25 @@ static struct hlist_head *tc_u_common_ha
#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)
@@ -343,7 +359,7 @@ static struct tc_u_common *tc_u_common_f
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;
@@ -372,7 +388,7 @@ 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);