Hi,
On Wed, Aug 11, 2021 at 05:03:19AM +0800, Zhouyi Zhou wrote:
> Hi Peter,
> I think comments in wait-type checks may benifit from some comments
> improvement.
Thanks for looking into this!
Even for an RFC patch, it's better that you write a proper commit log,
and note that you can put all this background information right after
the "---" line, if you think that will help people review it.
> I recklessly add Paul to signed-off-by, because I asked his opinion
> about comment in rcu_read_lock_bh part.
>
Probably a Suggested-by will suffice, but I leave that to Paul ;-)
> Thanks a lot
> Zhouyi
>
> Signed-off-by: Zhouyi Zhou <zhouzhouyi@xxxxxxxxx>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Please make you the last one in the "Signed-off-by" list, see
Documentation/process/submitting-patches.rst:
"Notably, the last Signed-off-by: must always be that of the developer
submitting the patch."
Regards,
Boqun
> ---
> include/linux/lockdep_types.h | 2 +-
> kernel/locking/lockdep.c | 2 +-
> kernel/rcu/update.c | 4 ++--
> 3 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/lockdep_types.h b/include/linux/lockdep_types.h
> index 3e726ace5c62..d22430840b53 100644
> --- 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 bf1c00c881e4..952d0ccf8776 100644
> --- 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 c21b38cc25e9..690b0cec7459 100644
> --- 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);
>
> --
> 2.25.1
>
