The start callback allows the caller to set up a context for the
dump callbacks. Presumably, the context can then be destroyed in
the done callback.
Signed-off-by: Tom Herbert <t...@herbertland.com>
---
include/linux/netlink.h | 2 ++
include/net/genetlink.h | 2 ++
net/netlink/af_netlink.c | 4 ++++
net/netlink/genetlink.c | 16 ++++++++++++++++
4 files changed, 24 insertions(+)
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 639e9b8..0b41959 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -131,6 +131,7 @@ netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
struct netlink_callback {
struct sk_buff *skb;
const struct nlmsghdr *nlh;
+ int (*start)(struct netlink_callback *);
int (*dump)(struct sk_buff * skb,
struct netlink_callback *cb);
int (*done)(struct netlink_callback *cb);
@@ -153,6 +154,7 @@ struct nlmsghdr *
__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int
flags);
struct netlink_dump_control {
+ int (*start)(struct netlink_callback *);
int (*dump)(struct sk_buff *skb, struct netlink_callback *);
int (*done)(struct netlink_callback *);
void *data;
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index a9af1cc..d76f2da 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -114,6 +114,7 @@ static inline void genl_info_net_set(struct genl_info
*info, struct net *net)
* @flags: flags
* @policy: attribute validation policy
* @doit: standard command callback
+ * @start: start callback for dumps
* @dumpit: callback for dumpers
* @done: completion callback for dumps
* @ops_list: operations list
@@ -122,6 +123,7 @@ struct genl_ops {
const struct nla_policy *policy;
int (*doit)(struct sk_buff *skb,
struct genl_info *info);
+ int (*start)(struct netlink_callback *cb);
int (*dumpit)(struct sk_buff *skb,
struct netlink_callback *cb);
int (*done)(struct netlink_callback *cb);
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 7f86d3b..25c6633 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2870,6 +2870,7 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff
*skb,
cb = &nlk->cb;
memset(cb, 0, sizeof(*cb));
+ cb->start = control->start;
cb->dump = control->dump;
cb->done = control->done;
cb->nlh = nlh;
@@ -2882,6 +2883,9 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff
*skb,
mutex_unlock(nlk->cb_mutex);
+ if (cb->start)
+ cb->start(cb);
+
ret = netlink_dump(sk);
sock_put(sk);
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 2ed5f96..3d111b0 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -513,6 +513,20 @@ void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
}
EXPORT_SYMBOL(genlmsg_put);
+static int genl_lock_start(struct netlink_callback *cb)
+{
+ /* our ops are always const - netlink API doesn't propagate that */
+ const struct genl_ops *ops = cb->data;
+ int rc = 0;
+
+ if (ops->start) {
+ genl_lock();
+ rc = ops->start(cb);
+ genl_unlock();
+ }
+ return rc;
+}
+
static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
{
/* our ops are always const - netlink API doesn't propagate that */
@@ -577,6 +591,7 @@ static int genl_family_rcv_msg(struct genl_family *family,
.module = family->module,
/* we have const, but the netlink API doesn't */
.data = (void *)ops,
+ .start = genl_lock_start,
.dump = genl_lock_dumpit,
.done = genl_lock_done,
};
@@ -588,6 +603,7 @@ static int genl_family_rcv_msg(struct genl_family *family,
} else {
struct netlink_dump_control c = {
.module = family->module,
+ .start = ops->start,
.dump = ops->dumpit,
.done = ops->done,
};
--
2.4.6
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