Re: [PATCH] locking/rwsem: add scoped guard for down_read_killable()

[Waiman Long]

On 5/29/26 10:16 AM, Oleg Nesterov wrote:
> We have lock guards for down_read_trylock/interruptible() but
> down_read_killable() is missing.
>
> At least scoped_cond_guard(rwsem_read_kill, signal->exec_update_lock)
> can have a lot of users: __pidfd_fget(), mm_access(), find_mm_struct(),
> kernel_migrate_pages(), and probably more.
>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> ---
>   include/linux/rwsem.h | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
> index 6a1a7bae5f81..f0cc72d8f0f2 100644
> --- a/include/linux/rwsem.h
> +++ b/include/linux/rwsem.h
> @@ -259,6 +259,7 @@ extern void up_write(struct rw_semaphore *sem) __releases(sem);
>   DEFINE_LOCK_GUARD_1(rwsem_read, struct rw_semaphore, down_read(_T->lock), up_read(_T->lock))
>   DEFINE_LOCK_GUARD_1_COND(rwsem_read, _try, down_read_trylock(_T->lock))
>   DEFINE_LOCK_GUARD_1_COND(rwsem_read, _intr, down_read_interruptible(_T->lock), _RET == 0)
> +DEFINE_LOCK_GUARD_1_COND(rwsem_read, _kill, down_read_killable(_T->lock), _RET == 0)
>   
>   DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
>   #define class_rwsem_read_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read, _T)
> @@ -266,6 +267,8 @@ DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_try, __acquires_shared(_T), __releases_sha
>   #define class_rwsem_read_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_try, _T)
>   DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_intr, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
>   #define class_rwsem_read_intr_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_intr, _T)
> +DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_kill, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
> +#define class_rwsem_read_kill_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_kill, _T)
>   
>   DEFINE_LOCK_GUARD_1(rwsem_write, struct rw_semaphore, down_write(_T->lock), up_write(_T->lock))
>   DEFINE_LOCK_GUARD_1_COND(rwsem_write, _try, down_write_trylock(_T->lock))
Acked-by: Waiman Long <longman@xxxxxxxxxx>