From: Mark Rustad <mark.d.rustad@intel.com>
Date: Tue, 26 Jun 2012 22:57:30 +0000 (-0700)
Subject: tcm_fc: Resolve suspicious RCU usage warnings
X-Git-Tag: v2.6.39-400.9.0~303^2~45
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ce1a42dbaaba41fa8106dc7a24c25249704c5f0b;p=users%2Fjedix%2Flinux-maple.git

tcm_fc: Resolve suspicious RCU usage warnings

commit 863555be0c81558b1af277addcf68acb8f778860 upstream.

Use rcu_dereference_protected to tell rcu that the ft_lport_lock
is held during ft_lport_create. This resolved "suspicious RCU usage"
warnings when debugging options are turned on.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Guangyu Sun <guangyu.sun@oracle.com>
---

diff --git a/drivers/target/tcm_fc/tfc_sess.c b/drivers/target/tcm_fc/tfc_sess.c
index 7491e21cc6ae..a40541c3df8c 100644
--- a/drivers/target/tcm_fc/tfc_sess.c
+++ b/drivers/target/tcm_fc/tfc_sess.c
@@ -64,7 +64,8 @@ static struct ft_tport *ft_tport_create(struct fc_lport *lport)
 	struct ft_tport *tport;
 	int i;
 
-	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
+	tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
+					  lockdep_is_held(&ft_lport_lock));
 	if (tport && tport->tpg)
 		return tport;