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Commit 516cba96 authored by Jakub Kicinski's avatar Jakub Kicinski
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Merge branch 'net-sched-cls_u32-use-proper-refcounts' 

Pedro Tammela says:

====================
net/sched: cls_u32: use proper refcounts

In u32 we are open coding refcounts of hashtables with integers which is
far from ideal. Update those with proper refcount and add a couple of
tests to tdc that exercise the refcounts explicitly.
====================

Link: https://lore.kernel.org/r/20231114141856.974326-1-pctammela@mojatatu.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 289354f2 54293e4d
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Showing with 75 additions and 18 deletions
net/sched/cls_u32.c
View file @ 516cba96
......@@ -71,7 +71,7 @@ struct tc_u_hnode {
struct tc_u_hnode __rcu *next;
u32 handle;
u32 prio;
int refcnt;
refcount_t refcnt;
unsigned int divisor;
struct idr handle_idr;
bool is_root;
......@@ -86,7 +86,7 @@ struct tc_u_hnode {
struct tc_u_common {
struct tc_u_hnode __rcu *hlist;
void *ptr;
int refcnt;
refcount_t refcnt;
struct idr handle_idr;
struct hlist_node hnode;
long knodes;
......@@ -359,7 +359,7 @@ static int u32_init(struct tcf_proto *tp)
if (root_ht == NULL)
return -ENOBUFS;
root_ht->refcnt++;
refcount_set(&root_ht->refcnt, 1);
root_ht->handle = tp_c ? gen_new_htid(tp_c, root_ht) : 0x80000000;
root_ht->prio = tp->prio;
root_ht->is_root = true;
......@@ -371,18 +371,20 @@ static int u32_init(struct tcf_proto *tp)
kfree(root_ht);
return -ENOBUFS;
}
refcount_set(&tp_c->refcnt, 1);
tp_c->ptr = key;
INIT_HLIST_NODE(&tp_c->hnode);
idr_init(&tp_c->handle_idr);
hlist_add_head(&tp_c->hnode, tc_u_hash(key));
} else {
refcount_inc(&tp_c->refcnt);
}
tp_c->refcnt++;
RCU_INIT_POINTER(root_ht->next, tp_c->hlist);
rcu_assign_pointer(tp_c->hlist, root_ht);
root_ht->refcnt++;
/* root_ht must be destroyed when tcf_proto is destroyed */
rcu_assign_pointer(tp->root, root_ht);
tp->data = tp_c;
return 0;
......@@ -393,7 +395,7 @@ static void __u32_destroy_key(struct tc_u_knode *n)
struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
tcf_exts_destroy(&n->exts);
if (ht && --ht->refcnt == 0)
if (ht && refcount_dec_and_test(&ht->refcnt))
kfree(ht);
kfree(n);
}
......@@ -601,8 +603,6 @@ static int u32_destroy_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht,
struct tc_u_hnode __rcu **hn;
struct tc_u_hnode *phn;
WARN_ON(--ht->refcnt);
u32_clear_hnode(tp, ht, extack);
hn = &tp_c->hlist;
......@@ -630,10 +630,10 @@ static void u32_destroy(struct tcf_proto *tp, bool rtnl_held,
WARN_ON(root_ht == NULL);
if (root_ht && --root_ht->refcnt == 1)
if (root_ht && refcount_dec_and_test(&root_ht->refcnt))
u32_destroy_hnode(tp, root_ht, extack);
if (--tp_c->refcnt == 0) {
if (refcount_dec_and_test(&tp_c->refcnt)) {
struct tc_u_hnode *ht;
hlist_del(&tp_c->hnode);
......@@ -645,7 +645,7 @@ static void u32_destroy(struct tcf_proto *tp, bool rtnl_held,
/* u32_destroy_key() will later free ht for us, if it's
* still referenced by some knode
*/
if (--ht->refcnt == 0)
if (refcount_dec_and_test(&ht->refcnt))
kfree_rcu(ht, rcu);
}
......@@ -674,7 +674,7 @@ static int u32_delete(struct tcf_proto *tp, void *arg, bool *last,
return -EINVAL;
}
if (ht->refcnt == 1) {
if (refcount_dec_if_one(&ht->refcnt)) {
u32_destroy_hnode(tp, ht, extack);
} else {
NL_SET_ERR_MSG_MOD(extack, "Can not delete in-use filter");
......@@ -682,7 +682,7 @@ static int u32_delete(struct tcf_proto *tp, void *arg, bool *last,
}
out:
*last = tp_c->refcnt == 1 && tp_c->knodes == 0;
*last = refcount_read(&tp_c->refcnt) == 1 && tp_c->knodes == 0;
return ret;
}
......@@ -766,14 +766,14 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
NL_SET_ERR_MSG_MOD(extack, "Not linking to root node");
return -EINVAL;
}
ht_down->refcnt++;
refcount_inc(&ht_down->refcnt);
}
ht_old = rtnl_dereference(n->ht_down);
rcu_assign_pointer(n->ht_down, ht_down);
if (ht_old)
ht_old->refcnt--;
refcount_dec(&ht_old->refcnt);
}
if (ifindex >= 0)
......@@ -852,7 +852,7 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp,
/* bump reference count as long as we hold pointer to structure */
if (ht)
ht->refcnt++;
refcount_inc(&ht->refcnt);
return new;
}
......@@ -932,7 +932,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
ht_old = rtnl_dereference(n->ht_down);
if (ht_old)
ht_old->refcnt++;
refcount_inc(&ht_old->refcnt);
}
__u32_destroy_key(new);
return err;
......@@ -980,7 +980,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
return err;
}
}
ht->refcnt = 1;
refcount_set(&ht->refcnt, 1);
ht->divisor = divisor;
ht->handle = handle;
ht->prio = tp->prio;
......
tools/testing/selftests/tc-testing/tc-tests/filters/u32.json
View file @ 516cba96
......@@ -272,5 +272,62 @@
"teardown": [
"$TC qdisc del dev $DEV1 parent root drr"
]
},
{
"id": "bd32",
"name": "Try to delete hashtable referenced by another u32 filter",
"category": [
"filter",
"u32"
],
"plugins": {
"requires": "nsPlugin"
},
"setup": [
"$TC qdisc add dev $DEV1 parent root handle 10: drr",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 handle 1: u32 divisor 1",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 u32 ht 800: match ip src any link 1:"
],
"cmdUnderTest": "$TC filter delete dev $DEV1 parent 10: prio 2 handle 1: u32",
"expExitCode": "2",
"verifyCmd": "$TC filter show dev $DEV1",
"matchPattern": "protocol ip pref 2 u32 chain 0 fh 1:",
"matchCount": "1",
"teardown": [
"$TC qdisc del dev $DEV1 parent root drr"
]
},
{
"id": "4585",
"name": "Delete small tree of u32 hashtables and filters",
"category": [
"filter",
"u32"
],
"plugins": {
"requires": "nsPlugin"
},
"setup": [
"$TC qdisc add dev $DEV1 parent root handle 10: drr",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 handle 1: u32 divisor 1",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 handle 2: u32 divisor 1",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 handle 3: u32 divisor 2",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 handle 4: u32 divisor 1",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 u32 ht 1: match ip src any action drop",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 u32 ht 2: match ip src any action drop",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 u32 ht 3: match ip src any link 2:",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 u32 ht 3: match ip src any link 1:",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 u32 ht 4: match ip src any action drop",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 u32 ht 800: match ip src any link 3:",
"$TC filter add dev $DEV1 parent 10:0 protocol ip prio 2 u32 ht 800: match ip src any link 4:"
],
"cmdUnderTest": "$TC filter delete dev $DEV1 parent 10:",
"expExitCode": "0",
"verifyCmd": "$TC filter show dev $DEV1",
"matchPattern": "protocol ip pref 2 u32",
"matchCount": "0",
"teardown": [
"$TC qdisc del dev $DEV1 parent root drr"
]
}
]
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