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

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Date:	Mon,  1 Nov 2010 20:15:09 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	dhowells@...hat.com, lizf@...fujitsu.com, paul.moore@...com,
	johannes@...solutions.net, dipankar@...ibm.com
Cc:	linux-kernel@...r.kernel.org,
	containers@...ts.linux-foundation.org, kvm@...r.kernel.org,
	Jiri Olsa <jolsa@...hat.com>
Subject: [PATCH 3/3] net - removing superfluous rcu_read_lock_held check

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>
---
 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;
 
-- 
1.7.1

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