add rcu_read_locked() to detect holding of rcu lock.

Signed-off-by: Chuang Xu <xuchuangxclwt@bytedance.com>
---
 include/qemu/rcu.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h
index b063c6fde8..42cbd0080f 100644
--- a/include/qemu/rcu.h
+++ b/include/qemu/rcu.h
@@ -119,6 +119,13 @@ static inline void rcu_read_unlock(void)
     }
 }
 
+static inline bool rcu_read_locked(void)
+{
+    struct rcu_reader_data *p_rcu_reader = get_ptr_rcu_reader();
+
+    return p_rcu_reader->depth > 0;
+}
+
 extern void synchronize_rcu(void);
 
 /*
-- 
2.20.1

Chuang Xu <xuchuangxclwt@bytedance.com> writes:

> add rcu_read_locked() to detect holding of rcu lock.
>
> Signed-off-by: Chuang Xu <xuchuangxclwt@bytedance.com>
> ---
>  include/qemu/rcu.h | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h
> index b063c6fde8..42cbd0080f 100644
> --- a/include/qemu/rcu.h
> +++ b/include/qemu/rcu.h
> @@ -119,6 +119,13 @@ static inline void rcu_read_unlock(void)
>      }
>  }
>  
> +static inline bool rcu_read_locked(void)

We use the locked suffix to indicate functions that should be called
with a lock held. Perhaps renaming this to rcu_read_is_locked() would
make the intent of the function clearer?

> +{
> +    struct rcu_reader_data *p_rcu_reader = get_ptr_rcu_reader();
> +
> +    return p_rcu_reader->depth > 0;
> +}
> +
>  extern void synchronize_rcu(void);
>  
>  /*


-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

On 2023/1/4 下午10:20, Alex Bennée wrote:
> Chuang Xu writes:
>
>> add rcu_read_locked() to detect holding of rcu lock.
>>
>> Signed-off-by: Chuang Xu
>> ---
>> include/qemu/rcu.h | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h
>> index b063c6fde8..42cbd0080f 100644
>> --- a/include/qemu/rcu.h
>> +++ b/include/qemu/rcu.h
>> @@ -119,6 +119,13 @@ static inline void rcu_read_unlock(void)
>> }
>> }
>>
>> +static inline bool rcu_read_locked(void)
> We use the locked suffix to indicate functions that should be called
> with a lock held. Perhaps renaming this to rcu_read_is_locked() would
> make the intent of the function clearer?

Yes, rcu_read_is_locked() do make the intent of the function clearer.
I'll rename the function in v5.

Thanks!

>> +{
>> + struct rcu_reader_data *p_rcu_reader = get_ptr_rcu_reader();
>> +
>> + return p_rcu_reader->depth > 0;
>> +}
>> +
>> extern void synchronize_rcu(void);
>>
>> /*
>