On Mon, 2011-11-14 at 15:51 -0500, Steven Rostedt wrote:

On Mon, 2011-11-14 at 18:39 +0100, John Kacur wrote:

quoted

On Mon, 14 Nov 2011, Paul E. McKenney wrote:

quoted

On Mon, Nov 14, 2011 at 02:44:43AM +0100, John Kacur wrote:

quoted

ERROR: "in_serving_softirq" [net/sched/cls_cgroup.ko] undefined!

The above can be fixed by exporting in_serving_softirq

Signed-off-by: John Kacur <jkacur@redhat.com>

The above patch was originally for 3.0.9-rt25
But I also needed to cherry-pick it for 3.2-rc1-rt1
---
 kernel/softirq.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 3db1d6f..5452432 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c

@@ -447,6 +447,7 @@ int in_serving_softirq(void)
 	preempt_enable();
 	return res;
 }
+EXPORT_SYMBOL(in_serving_softirq);

Why not EXPORT_SYMBOL_GPL?

I have no problem with that, note however that the upstream file has

EXPORT_SYMBOL(irq_stat);
EXPORT_SYMBOL(local_bh_disable);
EXPORT_SYMBOL(_local_bh_enable);
EXPORT_SYMBOL(local_bh_enable);
EXPORT_SYMBOL(local_bh_enable_ip);
EXPORT_SYMBOL(__tasklet_schedule);
EXPORT_SYMBOL(__tasklet_hi_schedule);
EXPORT_SYMBOL(__tasklet_hi_schedule_first);
EXPORT_SYMBOL(tasklet_init);
EXPORT_SYMBOL(tasklet_kill);
EXPORT_SYMBOL(__send_remote_softirq);
EXPORT_SYMBOL(send_remote_softirq);

Any reason we can't change all of those to EXPORT_SYMBOL_GPL?\\

IIRC, the point behind EXPORT_SYMBOL_GPL() is that, by using the call
you are using something that is a derivative of the code. Basically all
new functionality of the kernel is Linux specific and symbols exported
should be EXPORT_SYMBOL_GPL().

But, I also recall that we did not want to make things that are normal
OS operations under the EXPORT_SYMBOL_GPL(). This would include the
local_bh_enable/disable(), or anything that is called by generic
operations. For example, spin_lock() is not a GPL symbol, and if we add
some new functionality that causes all spin_locks() to call foo_bar(),
we must also make sure foo_bar() is also under just EXPORT_SYMBOL(),
otherwise, we just forced EXPORT_SYMBOL_GPL() on spin_lock().

Some of the above is probably just simple OS operations or are called by
static OS operation functions.

If we go that route, we might as well make everything
EXPORT_SYMBOL_GPL(), and be damn to those that use nVidia.

EXPORT_SYMBOL_GPL(migrate_disable) alone screws nVidia users, no?

I have an RT user who has no other viable choice than nVidia.  If the
above is true, that user will end up stuck at 2.6.33-rt until we get a
driver that actually works... or they deem linux to be a non-solution.

	-Mike