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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.

Sebastian Andrzej Siewior committed 4 years ago

Commit fbd9a2c1 parent d96657d2 files · +11 −1Browse files

Unified · Split

2 files
  1. include/linux/lockdep.h +7 −0
  2. net/core/dev.c +4 −1
include/linux/lockdep.h+7−0
@@ -329,6 +329,12 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); · 328 unmodified lines
329 329
330#define lockdep_assert_none_held_once() \330#define lockdep_assert_none_held_once() \
331 lockdep_assert_once(!current->lockdep_depth)331 lockdep_assert_once(!current->lockdep_depth)
332/*
333 * Ensure that softirq is handled within the callchain and not delayed and
334 * handled by chance.
335 */
336#define lockdep_assert_softirq_will_run() \
337 lockdep_assert_once(hardirq_count() | softirq_count())
332 338
333#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)339#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
334 340
@@ -414,6 +420,7 @@ extern int lockdep_is_held(const void *); · 79 unmodified lines
414#define lockdep_assert_held_read(l) do { (void)(l); } while (0)420#define lockdep_assert_held_read(l) do { (void)(l); } while (0)
415#define lockdep_assert_held_once(l) do { (void)(l); } while (0)421#define lockdep_assert_held_once(l) do { (void)(l); } while (0)
416#define lockdep_assert_none_held_once() do { } while (0)422#define lockdep_assert_none_held_once() do { } while (0)
423#define lockdep_assert_softirq_will_run() do { } while (0)
417 424
418#define lockdep_recursing(tsk) (0)425#define lockdep_recursing(tsk) (0)
419 426
net/core/dev.c+4−1
@@ -4265,6 +4265,9 @@ static inline void ____napi_schedule(struct softnet_data *sd, · 4264 unmodified lines
4265{4265{
4266 struct task_struct *thread;4266 struct task_struct *thread;
4267 4267
4268 lockdep_assert_softirq_will_run();
4269 lockdep_assert_irqs_disabled();
4270
4268 if (test_bit(NAPI_STATE_THREADED, &napi->state)) {4271 if (test_bit(NAPI_STATE_THREADED, &napi->state)) {
4269 /* Paired with smp_mb__before_atomic() in4272 /* Paired with smp_mb__before_atomic() in
4270 * napi_enable()/dev_set_threaded().4273 * napi_enable()/dev_set_threaded().
@@ -4872,7 +4875,7 @@ int __netif_rx(struct sk_buff *skb) · 601 unmodified lines
4872{4875{
4873 int ret;4876 int ret;
4874 4877
4875 lockdep_assert_once(hardirq_count() | softirq_count());4878 lockdep_assert_softirq_will_run();
4876 4879
4877 trace_netif_rx_entry(skb);4880 trace_netif_rx_entry(skb);
4878 ret = netif_rx_internal(skb);4881 ret = netif_rx_internal(skb);

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