lockdep: Improve comments in wait-type checks

Comments in wait-type checks be improved by mentioning the
PREEPT_RT kernel configure option.

Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20210811025920.20751-1-zhouzhouyi@gmail.com

diff --git a/include/linux/lockdep_types.h b/include/linux/lockdep_types.h
index 3e726ac..d224308 100644 (file)
--- a/include/linux/lockdep_types.h
+++ b/include/linux/lockdep_types.h
@@ -21,7 +21,7 @@ enum lockdep_wait_type {
        LD_WAIT_SPIN,           /* spin loops, raw_spinlock_t etc.. */
 
 #ifdef CONFIG_PROVE_RAW_LOCK_NESTING
-       LD_WAIT_CONFIG,         /* CONFIG_PREEMPT_LOCK, spinlock_t etc.. */
+       LD_WAIT_CONFIG,         /* preemptible in PREEMPT_RT, spinlock_t etc.. */
 #else
        LD_WAIT_CONFIG = LD_WAIT_SPIN,
 #endif

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index bfa0a34..4e63129 100644 (file)
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4671,7 +4671,7 @@ print_lock_invalid_wait_context(struct task_struct *curr,
 /*
  * Verify the wait_type context.
  *
- * This check validates we takes locks in the right wait-type order; that is it
+ * This check validates we take locks in the right wait-type order; that is it
  * ensures that we do not take mutexes inside spinlocks and do not attempt to
  * acquire spinlocks inside raw_spinlocks and the sort.
  *

diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index c21b38c..690b0ce 100644 (file)
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -247,7 +247,7 @@ struct lockdep_map rcu_lock_map = {
        .name = "rcu_read_lock",
        .key = &rcu_lock_key,
        .wait_type_outer = LD_WAIT_FREE,
-       .wait_type_inner = LD_WAIT_CONFIG, /* XXX PREEMPT_RCU ? */
+       .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT implies PREEMPT_RCU */
 };
 EXPORT_SYMBOL_GPL(rcu_lock_map);
 
@@ -256,7 +256,7 @@ struct lockdep_map rcu_bh_lock_map = {
        .name = "rcu_read_lock_bh",
        .key = &rcu_bh_lock_key,
        .wait_type_outer = LD_WAIT_FREE,
-       .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_LOCK also makes BH preemptible */
+       .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT makes BH preemptible. */
 };
 EXPORT_SYMBOL_GPL(rcu_bh_lock_map);