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| author |   Paul E. McKenney <paulmck@kernel.org> | 2021-07-28 12:28:27 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-09-15 11:37:50 -0700 |
| commit | a5c071ccfa1728508f31e61213ee795e4529d0d4 (patch) | |
| tree | 3b236ac03d771d84b53a8850a235312c830468a5 | |
| parent | rcu-tasks: Add trc_inspect_reader() checks for exiting critical section (diff) | |
| download | wireguard-linux-a5c071ccfa1728508f31e61213ee795e4529d0d4.tar.xz wireguard-linux-a5c071ccfa1728508f31e61213ee795e4529d0d4.zip | |
rcu-tasks: Remove second argument of rcu_read_unlock_trace_special()
The second argument of rcu_read_unlock_trace_special() is always zero.
When called from exit_tasks_rcu_finish_trace(), it is the constant
zero, and rcu_read_unlock_trace_special() doesn't get called from
rcu_read_unlock_trace() unless the value of local variable "nesting"
is zero because in that case the early return is taken instead.
This commit therefore removes the "nesting" argument from the
rcu_read_unlock_trace_special() function, substituting the constant
zero within that function. This commit also adds a WARN_ON_ONCE()
to rcu_read_lock_trace_held() in case non-zeroness some day appears.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| -rw-r--r-- | include/linux/rcupdate_trace.h | 5 | ||||
| -rw-r--r-- | kernel/rcu/tasks.h | 6 |
2 files changed, 6 insertions, 5 deletions
diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h index 86c8f6c98412..6f9c35817398 100644 --- a/include/linux/rcupdate_trace.h +++ b/include/linux/rcupdate_trace.h @@ -31,7 +31,7 @@ static inline int rcu_read_lock_trace_held(void) #ifdef CONFIG_TASKS_TRACE_RCU -void rcu_read_unlock_trace_special(struct task_struct *t, int nesting); +void rcu_read_unlock_trace_special(struct task_struct *t); /** * rcu_read_lock_trace - mark beginning of RCU-trace read-side critical section @@ -80,7 +80,8 @@ static inline void rcu_read_unlock_trace(void) WRITE_ONCE(t->trc_reader_nesting, nesting); return; // We assume shallow reader nesting. } - rcu_read_unlock_trace_special(t, nesting); + WARN_ON_ONCE(nesting != 0); + rcu_read_unlock_trace_special(t); } void call_rcu_tasks_trace(struct rcu_head *rhp, rcu_callback_t func); diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 8387e70e6b00..a3f4f9bd8c67 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -848,7 +848,7 @@ static void rcu_read_unlock_iw(struct irq_work *iwp) static DEFINE_IRQ_WORK(rcu_tasks_trace_iw, rcu_read_unlock_iw); /* If we are the last reader, wake up the grace-period kthread. */ -void rcu_read_unlock_trace_special(struct task_struct *t, int nesting) +void rcu_read_unlock_trace_special(struct task_struct *t) { int nq = READ_ONCE(t->trc_reader_special.b.need_qs); @@ -858,7 +858,7 @@ void rcu_read_unlock_trace_special(struct task_struct *t, int nesting) // Update .need_qs before ->trc_reader_nesting for irq/NMI handlers. if (nq) WRITE_ONCE(t->trc_reader_special.b.need_qs, false); - WRITE_ONCE(t->trc_reader_nesting, nesting); + WRITE_ONCE(t->trc_reader_nesting, 0); if (nq && atomic_dec_and_test(&trc_n_readers_need_end)) irq_work_queue(&rcu_tasks_trace_iw); } @@ -1200,7 +1200,7 @@ static void exit_tasks_rcu_finish_trace(struct task_struct *t) WARN_ON_ONCE(READ_ONCE(t->trc_reader_nesting)); WRITE_ONCE(t->trc_reader_nesting, 0); if (WARN_ON_ONCE(READ_ONCE(t->trc_reader_special.b.need_qs))) - rcu_read_unlock_trace_special(t, 0); + rcu_read_unlock_trace_special(t); } /** |