Commit fbd9a2ce authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by David S. Miller
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net: Add lockdep asserts to ____napi_schedule(). 



____napi_schedule() needs to be invoked with disabled interrupts due to
__raise_softirq_irqoff (in order not to corrupt the per-CPU list).
____napi_schedule() needs also to be invoked from an interrupt context
so that the raised-softirq is processed while the interrupt context is
left.

Add lockdep asserts for both conditions.
While this is the second time the irq/softirq check is needed, provide a
generic lockdep_assert_softirq_will_run() which is used by both caller.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d96657dc

include/linux/lockdep.h

+7 −0
Original line number Diff line number Diff line
@@ -329,6 +329,12 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); 


#define lockdep_assert_none_held_once()		\

	lockdep_assert_once(!current->lockdep_depth)

/*

 * Ensure that softirq is handled within the callchain and not delayed and

 * handled by chance.

 */

#define lockdep_assert_softirq_will_run()	\

	lockdep_assert_once(hardirq_count() | softirq_count())



#define lockdep_recursing(tsk)	((tsk)->lockdep_recursion)
@@ -414,6 +420,7 @@ extern int lockdep_is_held(const void *); 
#define lockdep_assert_held_read(l)		do { (void)(l); } while (0)

#define lockdep_assert_held_once(l)		do { (void)(l); } while (0)

#define lockdep_assert_none_held_once()	do { } while (0)

#define lockdep_assert_softirq_will_run()	do { } while (0)



#define lockdep_recursing(tsk)			(0)

net/core/dev.c

+4 −1
Original line number Diff line number Diff line
@@ -4265,6 +4265,9 @@ static inline void ____napi_schedule(struct softnet_data *sd, 
{

	struct task_struct *thread;



	lockdep_assert_softirq_will_run();

	lockdep_assert_irqs_disabled();



	if (test_bit(NAPI_STATE_THREADED, &napi->state)) {

		/* Paired with smp_mb__before_atomic() in

		 * napi_enable()/dev_set_threaded().
@@ -4872,7 +4875,7 @@ int __netif_rx(struct sk_buff *skb) 
{

	int ret;



	lockdep_assert_once(hardirq_count() | softirq_count());

	lockdep_assert_softirq_will_run();



	trace_netif_rx_entry(skb);

	ret = netif_rx_internal(skb);