Commit 4b706372 authored Jul 20, 2010 by Neil Horman Committed by David S. Miller Jul 20, 2010

drop_monitor: Add error code to detect duplicate state changes



	Patch to add -EAGAIN error to dropwatch netlink message handling code.
-EAGAIN will be returned anytime userspace attempts to transition the state of
the drop monitor service to a state that its already in.  That allows user space
to detect this condition, so it doesn't wait for a success ACK that will never
arrive.  Tested successfully by me

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent d79d9913

net/core/drop_monitor.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -223,6 +223,11 @@ static int set_all_monitor_traces(int state)

		spin_lock(&trace_state_lock);

		if (state == trace_state) {
		rc = -EAGAIN;
		goto out_unlock;
		}

		switch (state) {
		case TRACE_ON:
		rc \|= register_trace_kfree_skb(trace_kfree_skb_hit, NULL);
		@@ -251,11 +256,12 @@ static int set_all_monitor_traces(int state)

		if (!rc)
		trace_state = state;
		else
		rc = -EINPROGRESS;

		out_unlock:
		spin_unlock(&trace_state_lock);

		if (rc)
		return -EINPROGRESS;
		return rc;
		}