On Mon, Feb 20, 2006 at 02:31:05PM +0100, Patrick McHardy ([EMAIL PROTECTED])
wrote:
> Evgeniy Polyakov wrote:
> > Do not allocate and send new skb if there are no listeners.
> > cn_netlink_send() can return -ESRCH in this case.
>
> I don't think it makes sense to return an error. netlink_has_listeners()
> can return false positives, so no error would still not mean that the
> packet was really delivered. cn_netlink_send also doesn't propagate the
> return code of netlink_broadcast, so nobody seems to be interested
> anyway.
Yep, return code of netlink_broadcast() also should be returned back.
Main idea is to show, that if error is returned, then data 100% was not
delivered, no matter where it was dropped.
And alhtough nobody really does not care about it, since there is
sequence number inside, I think better to indicate if message was
dropped or not.
Signed-off-by: Evgeniy Polyakov <[EMAIL PROTECTED]>
diff --git a/Documentation/connector/connector.txt
b/Documentation/connector/connector.txt
index 57a314b..ad6e0ba 100644
--- a/Documentation/connector/connector.txt
+++ b/Documentation/connector/connector.txt
@@ -69,10 +69,11 @@ Unregisters new callback with connector
struct cb_id *id - unique connector's user identifier.
-void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask);
+int cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask);
Sends message to the specified groups. It can be safely called from
-any context, but may silently fail under strong memory pressure.
+softirq context, but may silently fail under strong memory pressure.
+If there are no listeners for given group -ESRCH can be returned.
struct cn_msg * - message header(with attached data).
u32 __group - destination group.
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index 505677f..89cc29f 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -97,6 +97,9 @@ int cn_netlink_send(struct cn_msg *msg,
group = __group;
}
+ if (!netlink_has_listeners(dev->nls), group)
+ return -ESRCH;
+
size = NLMSG_SPACE(sizeof(*msg) + msg->len);
skb = alloc_skb(size, gfp_mask);
@@ -111,9 +114,7 @@ int cn_netlink_send(struct cn_msg *msg,
NETLINK_CB(skb).dst_group = group;
- netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
-
- return 0;
+ return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
nlmsg_failure:
kfree_skb(skb);
--
Evgeniy Polyakov
-
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