2022-02-25 00:54:32

by Andrew Halaney

Subject: [PATCH] Documentation/locking/locktypes: Fix PREEMPT_RT _bh() description

With PREEMPT_RT the _bh() version of a spinlock leaves preemption
enabled, align the doc to say that instead of the opposite.

Reported-by: Leah Leshchinsky <[email protected]>
Signed-off-by: Andrew Halaney <[email protected]>
---
Documentation/locking/locktypes.rst | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/locking/locktypes.rst b/Documentation/locking/locktypes.rst
index 4fd7b70fcde1..bfa75ea1b66a 100644
--- a/Documentation/locking/locktypes.rst
+++ b/Documentation/locking/locktypes.rst
@@ -247,7 +247,7 @@ based on rt_mutex which changes the semantics:
Non-PREEMPT_RT kernels disable preemption to get this effect.

PREEMPT_RT kernels use a per-CPU lock for serialization which keeps
- preemption disabled. The lock disables softirq handlers and also
+ preemption enabled. The lock disables softirq handlers and also
prevents reentrancy due to task preemption.

PREEMPT_RT kernels preserve all other spinlock_t semantics:
--
2.35.1

2022-02-25 03:54:02

by Boqun Feng

Subject: Re: [PATCH] Documentation/locking/locktypes: Fix PREEMPT_RT _bh() description

On Thu, Feb 24, 2022 at 03:23:12PM -0600, Andrew Halaney wrote:
> With PREEMPT_RT the _bh() version of a spinlock leaves preemption
> enabled, align the doc to say that instead of the opposite.
>
> Reported-by: Leah Leshchinsky <[email protected]>
> Signed-off-by: Andrew Halaney <[email protected]>

Reviewed-by: Boqun Feng <[email protected]>

Regards,
Boqun

> ---
> Documentation/locking/locktypes.rst | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/locking/locktypes.rst b/Documentation/locking/locktypes.rst
> index 4fd7b70fcde1..bfa75ea1b66a 100644
> --- a/Documentation/locking/locktypes.rst
> +++ b/Documentation/locking/locktypes.rst
> @@ -247,7 +247,7 @@ based on rt_mutex which changes the semantics:
> Non-PREEMPT_RT kernels disable preemption to get this effect.
>
> PREEMPT_RT kernels use a per-CPU lock for serialization which keeps
> - preemption disabled. The lock disables softirq handlers and also
> + preemption enabled. The lock disables softirq handlers and also
> prevents reentrancy due to task preemption.
>
> PREEMPT_RT kernels preserve all other spinlock_t semantics:
> --
> 2.35.1
>

2022-03-04 18:16:58

by Jonathan Corbet

Subject: Re: [PATCH] Documentation/locking/locktypes: Fix PREEMPT_RT _bh() description

Andrew Halaney <[email protected]> writes:

> With PREEMPT_RT the _bh() version of a spinlock leaves preemption
> enabled, align the doc to say that instead of the opposite.
>
> Reported-by: Leah Leshchinsky <[email protected]>
> Signed-off-by: Andrew Halaney <[email protected]>
> ---
> Documentation/locking/locktypes.rst | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/locking/locktypes.rst b/Documentation/locking/locktypes.rst
> index 4fd7b70fcde1..bfa75ea1b66a 100644
> --- a/Documentation/locking/locktypes.rst
> +++ b/Documentation/locking/locktypes.rst
> @@ -247,7 +247,7 @@ based on rt_mutex which changes the semantics:
> Non-PREEMPT_RT kernels disable preemption to get this effect.
>
> PREEMPT_RT kernels use a per-CPU lock for serialization which keeps
> - preemption disabled. The lock disables softirq handlers and also
> + preemption enabled. The lock disables softirq handlers and also
> prevents reentrancy due to task preemption.

Applied, thanks.

jon