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authorDavide Caratti <dcaratti@redhat.com>2019-12-28 18:36:58 +0300
committerDavid S. Miller <davem@davemloft.net>2019-12-31 07:35:19 +0300
commita5b72a083da197b493c7ed1e5730d62d3199f7d6 (patch)
treef9e489c688e132f023ece79069c1014b99410798 /net
parent853697504de043ff0bfd815bd3a64de1dce73dc7 (diff)
downloadlinux-a5b72a083da197b493c7ed1e5730d62d3199f7d6.tar.xz
net/sched: add delete_empty() to filters and use it in cls_flower
Revert "net/sched: cls_u32: fix refcount leak in the error path of u32_change()", and fix the u32 refcount leak in a more generic way that preserves the semantic of rule dumping. On tc filters that don't support lockless insertion/removal, there is no need to guard against concurrent insertion when a removal is in progress. Therefore, for most of them we can avoid a full walk() when deleting, and just decrease the refcount, like it was done on older Linux kernels. This fixes situations where walk() was wrongly detecting a non-empty filter, like it happened with cls_u32 in the error path of change(), thus leading to failures in the following tdc selftests: 6aa7: (filter, u32) Add/Replace u32 with source match and invalid indev 6658: (filter, u32) Add/Replace u32 with custom hash table and invalid handle 74c2: (filter, u32) Add/Replace u32 filter with invalid hash table id On cls_flower, and on (future) lockless filters, this check is necessary: move all the check_empty() logic in a callback so that each filter can have its own implementation. For cls_flower, it's sufficient to check if no IDRs have been allocated. This reverts commit 275c44aa194b7159d1191817b20e076f55f0e620. Changes since v1: - document the need for delete_empty() when TCF_PROTO_OPS_DOIT_UNLOCKED is used, thanks to Vlad Buslov - implement delete_empty() without doing fl_walk(), thanks to Vlad Buslov - squash revert and new fix in a single patch, to be nice with bisect tests that run tdc on u32 filter, thanks to Dave Miller Fixes: 275c44aa194b ("net/sched: cls_u32: fix refcount leak in the error path of u32_change()") Fixes: 6676d5e416ee ("net: sched: set dedicated tcf_walker flag when tp is empty") Suggested-by: Jamal Hadi Salim <jhs@mojatatu.com> Suggested-by: Vlad Buslov <vladbu@mellanox.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Reviewed-by: Vlad Buslov <vladbu@mellanox.com> Tested-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sched/cls_api.c31
-rw-r--r--net/sched/cls_flower.c12
-rw-r--r--net/sched/cls_u32.c25
3 files changed, 17 insertions, 51 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 6a0eacafdb19..76e0d122616a 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -308,33 +308,12 @@ static void tcf_proto_put(struct tcf_proto *tp, bool rtnl_held,
tcf_proto_destroy(tp, rtnl_held, true, extack);
}
-static int walker_check_empty(struct tcf_proto *tp, void *fh,
- struct tcf_walker *arg)
+static bool tcf_proto_check_delete(struct tcf_proto *tp)
{
- if (fh) {
- arg->nonempty = true;
- return -1;
- }
- return 0;
-}
-
-static bool tcf_proto_is_empty(struct tcf_proto *tp, bool rtnl_held)
-{
- struct tcf_walker walker = { .fn = walker_check_empty, };
-
- if (tp->ops->walk) {
- tp->ops->walk(tp, &walker, rtnl_held);
- return !walker.nonempty;
- }
- return true;
-}
+ if (tp->ops->delete_empty)
+ return tp->ops->delete_empty(tp);
-static bool tcf_proto_check_delete(struct tcf_proto *tp, bool rtnl_held)
-{
- spin_lock(&tp->lock);
- if (tcf_proto_is_empty(tp, rtnl_held))
- tp->deleting = true;
- spin_unlock(&tp->lock);
+ tp->deleting = true;
return tp->deleting;
}
@@ -1751,7 +1730,7 @@ static void tcf_chain_tp_delete_empty(struct tcf_chain *chain,
* concurrently.
* Mark tp for deletion if it is empty.
*/
- if (!tp_iter || !tcf_proto_check_delete(tp, rtnl_held)) {
+ if (!tp_iter || !tcf_proto_check_delete(tp)) {
mutex_unlock(&chain->filter_chain_lock);
return;
}
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 0d125de54285..b0f42e62dd76 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -2773,6 +2773,17 @@ static void fl_bind_class(void *fh, u32 classid, unsigned long cl)
f->res.class = cl;
}
+static bool fl_delete_empty(struct tcf_proto *tp)
+{
+ struct cls_fl_head *head = fl_head_dereference(tp);
+
+ spin_lock(&tp->lock);
+ tp->deleting = idr_is_empty(&head->handle_idr);
+ spin_unlock(&tp->lock);
+
+ return tp->deleting;
+}
+
static struct tcf_proto_ops cls_fl_ops __read_mostly = {
.kind = "flower",
.classify = fl_classify,
@@ -2782,6 +2793,7 @@ static struct tcf_proto_ops cls_fl_ops __read_mostly = {
.put = fl_put,
.change = fl_change,
.delete = fl_delete,
+ .delete_empty = fl_delete_empty,
.walk = fl_walk,
.reoffload = fl_reoffload,
.hw_add = fl_hw_add,
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 66c6bcec16cb..a0e6fac613de 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -1108,33 +1108,10 @@ erridr:
return err;
}
-static bool u32_hnode_empty(struct tc_u_hnode *ht, bool *non_root_ht)
-{
- int i;
-
- if (!ht)
- return true;
- if (!ht->is_root) {
- *non_root_ht = true;
- return false;
- }
- if (*non_root_ht)
- return false;
- if (ht->refcnt < 2)
- return true;
-
- for (i = 0; i <= ht->divisor; i++) {
- if (rtnl_dereference(ht->ht[i]))
- return false;
- }
- return true;
-}
-
static void u32_walk(struct tcf_proto *tp, struct tcf_walker *arg,
bool rtnl_held)
{
struct tc_u_common *tp_c = tp->data;
- bool non_root_ht = false;
struct tc_u_hnode *ht;
struct tc_u_knode *n;
unsigned int h;
@@ -1147,8 +1124,6 @@ static void u32_walk(struct tcf_proto *tp, struct tcf_walker *arg,
ht = rtnl_dereference(ht->next)) {
if (ht->prio != tp->prio)
continue;
- if (u32_hnode_empty(ht, &non_root_ht))
- return;
if (arg->count >= arg->skip) {
if (arg->fn(tp, ht, arg) < 0) {
arg->stop = 1;