From 058a6c033488494a6b1477b05fe8e1a16e344462 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 2 Feb 2018 16:02:22 +0100 Subject: [PATCH] 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: a1b7c5fd7fe9 ("net: sched: add cls_u32 offload hooks for netdevs") Fixes: de5df63228fc ("net: sched: cls_u32 changes to knode must appear atomic to readers") Signed-off-by: Paolo Abeni Acked-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/cls_u32.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 60c892c36a60..e3c5e390ec23 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -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