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datapath: Avoid using stack larger than 1024.

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When compiling OvS-master on 4.4.0-81 kernel,
there is a warning:

    CC [M]  /root/ovs/datapath/linux/datapath.o
    /root/ovs/datapath/linux/datapath.c: In function
    'ovs_flow_cmd_set':
    /root/ovs/datapath/linux/datapath.c:1221:1: warning:
    the frame size of 1040 bytes is larger than 1024 bytes
    [-Wframe-larger-than=]

This patch factors out match-init and action-copy to avoid
"Wframe-larger-than=1024" warning. Because mask is only
used to get actions, we new a function to save some
stack space.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tonghao Zhang 2017-06-29 17:27:44 -07:00 committed by David S. Miller
parent 7e5988df26
commit 9cc9a5cb17
1 changed files with 58 additions and 23 deletions
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81
net/openvswitch/datapath.c
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@ -1090,6 +1090,58 @@ static struct sw_flow_actions *get_flow_actions(struct net *net,
return acts;
}
/* Factor out match-init and action-copy to avoid
* "Wframe-larger-than=1024" warning. Because mask is only
* used to get actions, we new a function to save some
* stack space.
*
* If there are not key and action attrs, we return 0
* directly. In the case, the caller will also not use the
* match as before. If there is action attr, we try to get
* actions and save them to *acts. Before returning from
* the function, we reset the match->mask pointer. Because
* we should not to return match object with dangling reference
* to mask.
* */
static int ovs_nla_init_match_and_action(struct net *net,
struct sw_flow_match *match,
struct sw_flow_key *key,
struct nlattr **a,
struct sw_flow_actions **acts,
bool log)
{
struct sw_flow_mask mask;
int error = 0;
if (a[OVS_FLOW_ATTR_KEY]) {
ovs_match_init(match, key, true, &mask);
error = ovs_nla_get_match(net, match, a[OVS_FLOW_ATTR_KEY],
a[OVS_FLOW_ATTR_MASK], log);
if (error)
goto error;
}
if (a[OVS_FLOW_ATTR_ACTIONS]) {
if (!a[OVS_FLOW_ATTR_KEY]) {
OVS_NLERR(log,
"Flow key attribute not present in set flow.");
return -EINVAL;
}
*acts = get_flow_actions(net, a[OVS_FLOW_ATTR_ACTIONS], key,
&mask, log);
if (IS_ERR(*acts)) {
error = PTR_ERR(*acts);
goto error;
}
}
/* On success, error is 0. */
error:
match->mask = NULL;
return error;
}
static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = sock_net(skb->sk);
@ -1097,7 +1149,6 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
struct ovs_header *ovs_header = info->userhdr;
struct sw_flow_key key;
struct sw_flow *flow;
struct sw_flow_mask mask;
struct sk_buff *reply = NULL;
struct datapath *dp;
struct sw_flow_actions *old_acts = NULL, *acts = NULL;
@ -1109,34 +1160,18 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
bool ufid_present;
ufid_present = ovs_nla_get_ufid(&sfid, a[OVS_FLOW_ATTR_UFID], log);
if (a[OVS_FLOW_ATTR_KEY]) {
ovs_match_init(&match, &key, true, &mask);
error = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY],
a[OVS_FLOW_ATTR_MASK], log);
} else if (!ufid_present) {
if (!a[OVS_FLOW_ATTR_KEY] && !ufid_present) {
OVS_NLERR(log,
"Flow set message rejected, Key attribute missing.");
error = -EINVAL;
return -EINVAL;
}
error = ovs_nla_init_match_and_action(net, &match, &key, a,
&acts, log);
if (error)
goto error;
/* Validate actions. */
if (a[OVS_FLOW_ATTR_ACTIONS]) {
if (!a[OVS_FLOW_ATTR_KEY]) {
OVS_NLERR(log,
"Flow key attribute not present in set flow.");
error = -EINVAL;
goto error;
}
acts = get_flow_actions(net, a[OVS_FLOW_ATTR_ACTIONS], &key,
&mask, log);
if (IS_ERR(acts)) {
error = PTR_ERR(acts);
goto error;
}
if (acts) {
/* Can allocate before locking if have acts. */
reply = ovs_flow_cmd_alloc_info(acts, &sfid, info, false,
ufid_flags);