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From: Amol Grover <frextrite@gmail.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	Joel Fernandes <joel@joelfernandes.org>,
	Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Amol Grover <frextrite@gmail.com>
Subject: [PATCH 2/3] drivers: target: target_core_tpg: Pass lockdep expression to RCU lists
Date: Fri, 10 Jan 2020 18:14:05 +0530	[thread overview]
Message-ID: <20200110124403.27882-2-frextrite@gmail.com> (raw)
In-Reply-To: <20200110124403.27882-1-frextrite@gmail.com>

tpg->tpg_lun_hlist is traversed with hlist_for_each_entry_rcu
outside an RCU read-side critical section but under the
protection of tpg->tpg_lun_mutex.

Hence, add the corresponding lockdep expression to the list traversal
primitive to silence false-positive lockdep warnings, and
harden RCU lists.

Add macro for the corresponding lockdep expression to make the code
clean and concise.

Signed-off-by: Amol Grover <frextrite@gmail.com>
---
 drivers/target/target_core_tpg.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index d24e0a3ba3ff..bc1c5dda81bf 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -30,6 +30,9 @@
 #include "target_core_pr.h"
 #include "target_core_ua.h"
 
+#define tpg_lun_mutex_held() \
+	lockdep_is_held(&tpg->tpg_lun_mutex)
+
 extern struct se_device *g_lun0_dev;
 
 /*	__core_tpg_get_initiator_node_acl():
@@ -110,12 +113,12 @@ void core_tpg_add_node_to_devs(
 	struct se_device *dev;
 
 	mutex_lock(&tpg->tpg_lun_mutex);
-	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) {
+	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link,
+							tpg_lun_mutex_held()) {
 		if (lun_orig && lun != lun_orig)
 			continue;
 
-		dev = rcu_dereference_check(lun->lun_se_dev,
-					    lockdep_is_held(&tpg->tpg_lun_mutex));
+		dev = rcu_dereference_check(lun->lun_se_dev, tpg_lun_mutex_held());
 		/*
 		 * By default in LIO-Target $FABRIC_MOD,
 		 * demo_mode_write_protect is ON, or READ_ONLY;
-- 
2.24.1


WARNING: multiple messages have this Message-ID (diff)
From: Amol Grover <frextrite@gmail.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
	target-devel@vger.kernel.org,
	Joel Fernandes <joel@joelfernandes.org>,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: [PATCH 2/3] drivers: target: target_core_tpg: Pass lockdep expression to RCU lists
Date: Fri, 10 Jan 2020 12:56:05 +0000	[thread overview]
Message-ID: <20200110124403.27882-2-frextrite@gmail.com> (raw)
In-Reply-To: <20200110124403.27882-1-frextrite@gmail.com>

tpg->tpg_lun_hlist is traversed with hlist_for_each_entry_rcu
outside an RCU read-side critical section but under the
protection of tpg->tpg_lun_mutex.

Hence, add the corresponding lockdep expression to the list traversal
primitive to silence false-positive lockdep warnings, and
harden RCU lists.

Add macro for the corresponding lockdep expression to make the code
clean and concise.

Signed-off-by: Amol Grover <frextrite@gmail.com>
---
 drivers/target/target_core_tpg.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index d24e0a3ba3ff..bc1c5dda81bf 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -30,6 +30,9 @@
 #include "target_core_pr.h"
 #include "target_core_ua.h"
 
+#define tpg_lun_mutex_held() \
+	lockdep_is_held(&tpg->tpg_lun_mutex)
+
 extern struct se_device *g_lun0_dev;
 
 /*	__core_tpg_get_initiator_node_acl():
@@ -110,12 +113,12 @@ void core_tpg_add_node_to_devs(
 	struct se_device *dev;
 
 	mutex_lock(&tpg->tpg_lun_mutex);
-	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) {
+	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link,
+							tpg_lun_mutex_held()) {
 		if (lun_orig && lun != lun_orig)
 			continue;
 
-		dev = rcu_dereference_check(lun->lun_se_dev,
-					    lockdep_is_held(&tpg->tpg_lun_mutex));
+		dev = rcu_dereference_check(lun->lun_se_dev, tpg_lun_mutex_held());
 		/*
 		 * By default in LIO-Target $FABRIC_MOD,
 		 * demo_mode_write_protect is ON, or READ_ONLY;
-- 
2.24.1

WARNING: multiple messages have this Message-ID (diff)
From: Amol Grover <frextrite@gmail.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
	target-devel@vger.kernel.org,
	Joel Fernandes <joel@joelfernandes.org>,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Linux-kernel-mentees] [PATCH 2/3] drivers: target: target_core_tpg: Pass lockdep expression to RCU lists
Date: Fri, 10 Jan 2020 18:14:05 +0530	[thread overview]
Message-ID: <20200110124403.27882-2-frextrite@gmail.com> (raw)
In-Reply-To: <20200110124403.27882-1-frextrite@gmail.com>

tpg->tpg_lun_hlist is traversed with hlist_for_each_entry_rcu
outside an RCU read-side critical section but under the
protection of tpg->tpg_lun_mutex.

Hence, add the corresponding lockdep expression to the list traversal
primitive to silence false-positive lockdep warnings, and
harden RCU lists.

Add macro for the corresponding lockdep expression to make the code
clean and concise.

Signed-off-by: Amol Grover <frextrite@gmail.com>
---
 drivers/target/target_core_tpg.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index d24e0a3ba3ff..bc1c5dda81bf 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -30,6 +30,9 @@
 #include "target_core_pr.h"
 #include "target_core_ua.h"
 
+#define tpg_lun_mutex_held() \
+	lockdep_is_held(&tpg->tpg_lun_mutex)
+
 extern struct se_device *g_lun0_dev;
 
 /*	__core_tpg_get_initiator_node_acl():
@@ -110,12 +113,12 @@ void core_tpg_add_node_to_devs(
 	struct se_device *dev;
 
 	mutex_lock(&tpg->tpg_lun_mutex);
-	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) {
+	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link,
+							tpg_lun_mutex_held()) {
 		if (lun_orig && lun != lun_orig)
 			continue;
 
-		dev = rcu_dereference_check(lun->lun_se_dev,
-					    lockdep_is_held(&tpg->tpg_lun_mutex));
+		dev = rcu_dereference_check(lun->lun_se_dev, tpg_lun_mutex_held());
 		/*
 		 * By default in LIO-Target $FABRIC_MOD,
 		 * demo_mode_write_protect is ON, or READ_ONLY;
-- 
2.24.1

_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

  reply	other threads:[~2020-01-10 12:45 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-10 12:44 [PATCH 1/3] drivers: target: target_core_device: Pass lockdep expression to RCU lists Amol Grover
2020-01-10 12:56 ` Amol Grover
2020-01-10 12:44 ` [Linux-kernel-mentees] " Amol Grover
2020-01-10 12:44 ` Amol Grover [this message]
2020-01-10 12:56   ` [PATCH 2/3] drivers: target: target_core_tpg: " Amol Grover
2020-01-10 12:44   ` [Linux-kernel-mentees] " Amol Grover
2020-01-10 12:44 ` [PATCH 3/3] drivers: target: tcm_fc: tfc_sess: " Amol Grover
2020-01-10 12:56   ` Amol Grover
2020-01-10 12:44   ` [Linux-kernel-mentees] " Amol Grover

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