The use of xchg() hasn't been necessary since 2.2.something when proper
locking was added to packet schedulers. In the case of classifiers they
mostly weren't even necessary before that since they're mainly used
to assign a NULL pointer to the filter root in the ->destroy path;
the root is destroyed immediately after that.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The classifier should cover the most common use case and will work
without any special configuration.
The principle of the classifier is to directly access the
task_struct via get_current(). In order for this to work,
classification requests from softirqs must be ignored. This is
not a problem because the vast majority of packets in softirq
context are not assigned to a task anyway. For this to work, a
mechanism is needed to trace softirq context.
This repost goes back to the method of relying on the number of
nested bh disable calls for the sake of not adding too much
complexity and the option to come up with something more reliable
if actually needed.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
