On 05/08/2013 04:37 PM, Johannes Berg wrote:
On Wed, 2013-05-08 at 10:36 +0200, Johannes Berg wrote:
On Wed, 2013-05-08 at 16:31 +0800, Wei.Yang@xxxxxxxxxxxxx wrote:
From: Wei Yang <Wei.Yang@xxxxxxxxxxxxx>
In case of RT kernel, the return value of softirq_count() always
equal to 0, we need to use in_serving_softirq to decide whether
the current context is in softirq context.
- WARN_ON_ONCE(softirq_count() == 0);
+ WARN_ON_ONCE(!in_serving_softirq());
As I understand the code, I don't believe this change to be correct. The
function can happily run with softirqs disabled (e.g.
local_bh_disable()), for example by being called via ieee80211_rx_ni().
As I understand in_serving_softirq(), it checks that it's actually
inside handling a softirq, no?
Arguably, it should be
WARN_ON_ONCE(!in_softirq());
but that's equivalent:
Yeah, but the softirq is threaded in rt kernel, the softirq_count always
return 0. The warning should always happen with rt kernel.
Wei
include/linux/hardirq.h
* in_softirq - Are we currently processing softirq or have bh disabled?
#define in_softirq() (softirq_count())
johannes
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