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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/sched/cls_u32.c
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/sched/cls_u32.c')
-rw-r--r--net/sched/cls_u32.c25
1 files changed, 0 insertions, 25 deletions
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;