Subject: Re: [PATCH net-next-2.6] net: introduce rcu_dereference_read_lock_or_rtnl

From: Jarek Poplawski <[email-masked]>
Date: Tue, 07 Sep 2010 22:49:28 +0200

Eric Dumazet wrote, On 09/07/2010 10:11 PM:

> We use rcu_dereference_check(p, rcu_read_lock_held() ||
> lockdep_rtnl_is_held()) several times in network stack.
> 
> More usages to come too, so its time to create a helper.
> 
> Signed-off-by: Eric Dumazet <[email-masked]>
> ---
> include/linux/rtnetlink.h |   12 ++++++++++++
> 
> diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
> index 58d4449..5ba48bb 100644
> --- a/include/linux/rtnetlink.h
> +++ b/include/linux/rtnetlink.h
> @@ -745,10 +745,22 @@ extern void rtnl_lock(void);
>  extern void rtnl_unlock(void);
>  extern int rtnl_trylock(void);
>  extern int rtnl_is_locked(void);
> +
>  #ifdef CONFIG_PROVE_LOCKING
>  extern int lockdep_rtnl_is_held(void);
>  #endif /* #ifdef CONFIG_PROVE_LOCKING */
>  
> +/**
> + * rcu_dereference_read_lock_or_rtnl - rcu_dereference with debug checking
> + * @p: The pointer to read, prior to dereferencing
> + *
> + * Do an rcu_dereference(p), but check caller either holds rcu_read_lock()
> + * or RTNL
> + */
> +#define rcu_dereference_read_lock_or_rtnl(p)

My proposal is to shorten the name, and since rcu_read_lock
part seems obvious, maybe rcu_dereference_rtnl() only?

Jarek P.

				\
> +		rcu_dereference_check(p, rcu_read_lock_held() ||	\
> +					 lockdep_rtnl_is_held());
> +
>  extern void rtnetlink_init(void);
>  extern void __rtnl_unlock(void);
>  
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to [email-masked]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>