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cls_u32: add missing RCU annotation. 

In a couple of points of the control path, n->ht_down is currently
accessed without the required RCU annotation. The accesses are
safe, but sparse complaints. Since we already held the
rtnl lock, let use rtnl_dereference().

Fixes: a1b7c5fd7f ("net: sched: add cls_u32 offload hooks for netdevs")
Fixes: de5df63228 ("net: sched: cls_u32 changes to knode must appear atomic to readers")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2018-02-02 16:02:22 +01:00 committed by David S. Miller
parent 0072f0c40b
commit 058a6c0334
1 changed files with 7 additions and 5 deletions
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12
net/sched/cls_u32.c
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@ -548,6 +548,7 @@ static void u32_remove_hw_knode(struct tcf_proto *tp, struct tc_u_knode *n,
static int u32_replace_hw_knode(struct tcf_proto *tp, struct tc_u_knode *n,
u32 flags, struct netlink_ext_ack *extack)
{
struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
struct tcf_block *block = tp->chain->block;
struct tc_cls_u32_offload cls_u32 = {};
bool skip_sw = tc_skip_sw(flags);
@ -567,7 +568,7 @@ static int u32_replace_hw_knode(struct tcf_proto *tp, struct tc_u_knode *n,
cls_u32.knode.sel = &n->sel;
cls_u32.knode.exts = &n->exts;
if (n->ht_down)
cls_u32.knode.link_handle = n->ht_down->handle;
cls_u32.knode.link_handle = ht->handle;
err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSU32, &cls_u32, skip_sw);
if (err < 0) {
@ -855,8 +856,9 @@ static void u32_replace_knode(struct tcf_proto *tp, struct tc_u_common *tp_c,
static struct tc_u_knode *u32_init_knode(struct tcf_proto *tp,
struct tc_u_knode *n)
{
struct tc_u_knode *new;
struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
struct tc_u32_sel *s = &n->sel;
struct tc_u_knode *new;
new = kzalloc(sizeof(*n) + s->nkeys*sizeof(struct tc_u32_key),
GFP_KERNEL);
@ -874,11 +876,11 @@ static struct tc_u_knode *u32_init_knode(struct tcf_proto *tp,
new->fshift = n->fshift;
new->res = n->res;
new->flags = n->flags;
RCU_INIT_POINTER(new->ht_down, n->ht_down);
RCU_INIT_POINTER(new->ht_down, ht);
/* bump reference count as long as we hold pointer to structure */
if (new->ht_down)
new->ht_down->refcnt++;
if (ht)
ht->refcnt++;
#ifdef CONFIG_CLS_U32_PERF
/* Statistics may be incremented by readers during update