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authorTom Herbert <tom@herbertland.com>2015-12-15 15:41:37 -0800
committerDavid S. Miller <davem@davemloft.net>2015-12-15 23:25:20 -0500
commitfc9e50f5a5a4e1fa9ba2756f745a13e693cf6a06 (patch)
tree168120764bcdbba0aad5859c9044f7dd84eb4350 /net/netlink
parent3502cad73c4bbf8f6365d539e814159275252c59 (diff)
downloadlinux-fc9e50f5a5a4e1fa9ba2756f745a13e693cf6a06.tar.gz
netlink: add a start callback for starting a netlink dump
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 <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
-rw-r--r--net/netlink/af_netlink.c4
-rw-r--r--net/netlink/genetlink.c16
2 files changed, 20 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 59651af8cc27..81dc1bb6e016 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2915,6 +2915,7 @@ 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;
@@ -2927,6 +2928,9 @@ 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 bc0e504f33a6..8e63662c6fb0 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,
 			};