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: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 467b942..0cc65d2 100644 (file)
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -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)
 

diff --git a/net/core/dev.c b/net/core/dev.c
index 8d25ec5..75bab5b 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -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);