linux-kernel - Re: [PATCH 3/3] net - removing superfluous rcu_read_lock

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Message-ID: <1288648032.5167.0.camel@sifl>
Date:	Mon, 01 Nov 2010 17:47:12 -0400
From:	Paul Moore <paul.moore@...com>
To:	Jiri Olsa <jolsa@...hat.com>
Cc:	dhowells@...hat.com, lizf@...fujitsu.com,
	johannes@...solutions.net, dipankar@...ibm.com,
	linux-kernel@...r.kernel.org,
	containers@...ts.linux-foundation.org, kvm@...r.kernel.org
Subject: Re: [PATCH 3/3] net - removing superfluous rcu_read_lock_held check

On Mon, 2010-11-01 at 20:15 +0100, Jiri Olsa wrote:
> hi,
> the rcu_dereference_check is defined as
> 
> 	#define rcu_dereference_check(p, c) \
> 	   __rcu_dereference_check((p), rcu_read_lock_held() || (c), __rcu)
> 
> so the caller does not need to specify rcu_read_lock_held() condition.
> 
> wbr,
> jirka
> 
> 
> Signed-off-by: Jiri Olsa <jolsa@...hat.com>

The NetLabel changes look fine to me; thanks for the cleanup.

> ---
>  include/linux/rtnetlink.h          |    3 +--
>  include/net/sock.h                 |    3 +--
>  net/mac80211/sta_info.c            |    4 ----
>  net/netlabel/netlabel_domainhash.c |    3 +--
>  net/netlabel/netlabel_unlabeled.c  |    3 +--
>  5 files changed, 4 insertions(+), 12 deletions(-)
> 
> diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
> index d42f274..dfe5ba1 100644
> --- a/include/linux/rtnetlink.h
> +++ b/include/linux/rtnetlink.h
> @@ -758,8 +758,7 @@ extern int lockdep_rtnl_is_held(void);
>   * or RTNL. Note : Please prefer rtnl_dereference() or rcu_dereference()
>   */
>  #define rcu_dereference_rtnl(p)					\
> -	rcu_dereference_check(p, rcu_read_lock_held() ||	\
> -				 lockdep_rtnl_is_held())
> +	rcu_dereference_check(p, lockdep_rtnl_is_held())
>  
>  /**
>   * rtnl_dereference - fetch RCU pointer when updates are prevented by RTNL
> diff --git a/include/net/sock.h b/include/net/sock.h
> index c7a7362..bee3e9c 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -1274,8 +1274,7 @@ extern unsigned long sock_i_ino(struct sock *sk);
>  static inline struct dst_entry *
>  __sk_dst_get(struct sock *sk)
>  {
> -	return rcu_dereference_check(sk->sk_dst_cache, rcu_read_lock_held() ||
> -						       sock_owned_by_user(sk) ||
> +	return rcu_dereference_check(sk->sk_dst_cache, sock_owned_by_user(sk) ||
>  						       lockdep_is_held(&sk->sk_lock.slock));
>  }
>  
> diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
> index 6d8f897..c879217 100644
> --- a/net/mac80211/sta_info.c
> +++ b/net/mac80211/sta_info.c
> @@ -94,7 +94,6 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
>  	struct sta_info *sta;
>  
>  	sta = rcu_dereference_check(local->sta_hash[STA_HASH(addr)],
> -				    rcu_read_lock_held() ||
>  				    lockdep_is_held(&local->sta_lock) ||
>  				    lockdep_is_held(&local->sta_mtx));
>  	while (sta) {
> @@ -102,7 +101,6 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
>  		    memcmp(sta->sta.addr, addr, ETH_ALEN) == 0)
>  			break;
>  		sta = rcu_dereference_check(sta->hnext,
> -					    rcu_read_lock_held() ||
>  					    lockdep_is_held(&local->sta_lock) ||
>  					    lockdep_is_held(&local->sta_mtx));
>  	}
> @@ -120,7 +118,6 @@ struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
>  	struct sta_info *sta;
>  
>  	sta = rcu_dereference_check(local->sta_hash[STA_HASH(addr)],
> -				    rcu_read_lock_held() ||
>  				    lockdep_is_held(&local->sta_lock) ||
>  				    lockdep_is_held(&local->sta_mtx));
>  	while (sta) {
> @@ -129,7 +126,6 @@ struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
>  		    memcmp(sta->sta.addr, addr, ETH_ALEN) == 0)
>  			break;
>  		sta = rcu_dereference_check(sta->hnext,
> -					    rcu_read_lock_held() ||
>  					    lockdep_is_held(&local->sta_lock) ||
>  					    lockdep_is_held(&local->sta_mtx));
>  	}
> diff --git a/net/netlabel/netlabel_domainhash.c b/net/netlabel/netlabel_domainhash.c
> index d37b7f8..82795a4 100644
> --- a/net/netlabel/netlabel_domainhash.c
> +++ b/net/netlabel/netlabel_domainhash.c
> @@ -55,8 +55,7 @@ struct netlbl_domhsh_tbl {
>   * should be okay */
>  static DEFINE_SPINLOCK(netlbl_domhsh_lock);
>  #define netlbl_domhsh_rcu_deref(p) \
> -	rcu_dereference_check(p, rcu_read_lock_held() || \
> -				 lockdep_is_held(&netlbl_domhsh_lock))
> +	rcu_dereference_check(p, lockdep_is_held(&netlbl_domhsh_lock))
>  static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL;
>  static struct netlbl_dom_map *netlbl_domhsh_def = NULL;
>  
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index e2b0a68..d2f982f 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -116,8 +116,7 @@ struct netlbl_unlhsh_walk_arg {
>   * hash table should be okay */
>  static DEFINE_SPINLOCK(netlbl_unlhsh_lock);
>  #define netlbl_unlhsh_rcu_deref(p) \
> -	rcu_dereference_check(p, rcu_read_lock_held() || \
> -				 lockdep_is_held(&netlbl_unlhsh_lock))
> +	rcu_dereference_check(p, lockdep_is_held(&netlbl_unlhsh_lock))
>  static struct netlbl_unlhsh_tbl *netlbl_unlhsh = NULL;
>  static struct netlbl_unlhsh_iface *netlbl_unlhsh_def = NULL;
>  

-- 
paul moore
linux @ hp


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