[PATCH net-next 6/9] genetlink: bring back per op policy

[Jakub Kicinski]

Add policy to the struct genl_ops structure, this time
with maxattr, so it can be used properly.

Propagate .policy and .maxattr from the family
in genl_get_cmd() if needed, this way the rest of the
code does not have to worry if the policy is per op
or global.

Signed-off-by: Jakub Kicinski <k...@kernel.org>
Reviewed-by: Johannes Berg <johan...@sipsolutions.net>
---
 include/net/genetlink.h |  4 ++++
 net/netlink/genetlink.c | 18 +++++++++++++-----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index 8ea1fc1ed1c7..cb35625d001e 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -137,6 +137,8 @@ struct genl_small_ops {
  * @cmd: command identifier
  * @internal_flags: flags used by the family
  * @flags: flags
+ * @maxattr: maximum number of attributes supported
+ * @policy: netlink policy (takes precedence over family policy)
  * @doit: standard command callback
  * @start: start callback for dumps
  * @dumpit: callback for dumpers
@@ -149,6 +151,8 @@ struct genl_ops {
        int                    (*dumpit)(struct sk_buff *skb,
                                         struct netlink_callback *cb);
        int                    (*done)(struct netlink_callback *cb);
+       const struct nla_policy *policy;
+       unsigned int            maxattr;
        u8                      cmd;
        u8                      internal_flags;
        u8                      flags;
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 183f01e62ae9..2a3608cfb179 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -116,6 +116,11 @@ static void genl_op_from_full(const struct genl_family 
*family,
                              unsigned int i, struct genl_ops *op)
 {
        *op = family->ops[i];
+
+       if (!op->maxattr)
+               op->maxattr = family->maxattr;
+       if (!op->policy)
+               op->policy = family->policy;
 }
 
 static int genl_get_cmd_full(u8 cmd, const struct genl_family *family,
@@ -142,6 +147,9 @@ static void genl_op_from_small(const struct genl_family 
*family,
        op->internal_flags = family->small_ops[i].internal_flags;
        op->flags       = family->small_ops[i].flags;
        op->validate    = family->small_ops[i].validate;
+
+       op->maxattr = family->maxattr;
+       op->policy = family->policy;
 }
 
 static int genl_get_cmd_small(u8 cmd, const struct genl_family *family,
@@ -529,16 +537,16 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family 
*family,
        struct nlattr **attrbuf;
        int err;
 
-       if (!family->maxattr)
+       if (!ops->maxattr)
                return NULL;
 
-       attrbuf = kmalloc_array(family->maxattr + 1,
+       attrbuf = kmalloc_array(ops->maxattr + 1,
                                sizeof(struct nlattr *), GFP_KERNEL);
        if (!attrbuf)
                return ERR_PTR(-ENOMEM);
 
-       err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
-                           family->policy, validate, extack);
+       err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
+                           validate, extack);
        if (err) {
                kfree(attrbuf);
                return ERR_PTR(err);
@@ -845,7 +853,7 @@ static int ctrl_fill_info(const struct genl_family *family, 
u32 portid, u32 seq,
                                op_flags |= GENL_CMD_CAP_DUMP;
                        if (op.doit)
                                op_flags |= GENL_CMD_CAP_DO;
-                       if (family->policy)
+                       if (op.policy)
                                op_flags |= GENL_CMD_CAP_HASPOL;
 
                        nest = nla_nest_start_noflag(skb, i + 1);
-- 
2.26.2