drivers: target: target_core_device: Pass lockdep expression to RCU lists

PATCH New Amol Grover 1 participant 3 messages Jan 10, 2020

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Amol Grover

author

2020-01-10 12:45 UTC #0 lore raw

PATCH 1/3 drivers: target: target_core_device: Pass lockdep expression to RCU lists

nacl->lun_entry_hlist is traversed with hlist_for_each_entry_rcu outside an RCU read-side critical section but under the protection of nacl->lun_entry_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 <[email protected]>

---
 drivers/target/target_core_device.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

drivers/target/target_core_device.c +12 -6

index 2d19f0e332b0..2d1277a83916 100644
@@ -36,6 +36,9 @@
 #include "target_core_pr.h"
 #include "target_core_ua.h"
 
+#define lun_entry_mutex_held() \
+	lockdep_is_held(&nacl->lun_entry_mutex)
+
 static DEFINE_MUTEX(device_mutex);
 static LIST_HEAD(device_list);
 static DEFINE_IDR(devices_idr);

@@ -247,9 +250,10 @@ void core_free_device_list_for_node(
 	struct se_dev_entry *deve;
 
 	mutex_lock(&nacl->lun_entry_mutex);
-	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
+	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link,
+							lun_entry_mutex_held()) {
 		struct se_lun *lun = rcu_dereference_check(deve->se_lun,
-					lockdep_is_held(&nacl->lun_entry_mutex));
+							lun_entry_mutex_held());
 		core_disable_device_list_for_node(lun, deve, nacl, tpg);
 	}
 	mutex_unlock(&nacl->lun_entry_mutex);

@@ -276,7 +280,8 @@ struct se_dev_entry *target_nacl_find_deve(struct se_node_acl *nacl, u64 mapped_
 {
 	struct se_dev_entry *deve;
 
-	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
+	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link,
+				rcu_read_lock_held() || lun_entry_mutex_held())
 		if (deve->mapped_lun == mapped_lun)
 			return deve;

@@ -339,7 +344,7 @@ int core_enable_device_list_for_node(
 	orig = target_nacl_find_deve(nacl, mapped_lun);
 	if (orig && orig->se_lun) {
 		struct se_lun *orig_lun = rcu_dereference_check(orig->se_lun,
-					lockdep_is_held(&nacl->lun_entry_mutex));
+							lun_entry_mutex_held());
 
 		if (orig_lun != lun) {
 			pr_err("Existing orig->se_lun doesn't match new lun"

@@ -460,9 +465,10 @@ void core_clear_lun_from_tpg(struct se_lun *lun, struct se_portal_group *tpg)
 	list_for_each_entry(nacl, &tpg->acl_node_list, acl_list) {
 
 		mutex_lock(&nacl->lun_entry_mutex);
-		hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
+		hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link,
+							lun_entry_mutex_held()) {
 			struct se_lun *tmp_lun = rcu_dereference_check(deve->se_lun,
-					lockdep_is_held(&nacl->lun_entry_mutex));
+							lun_entry_mutex_held());
 
 			if (lun != tmp_lun)
 				continue;

Signature · 1 line

2.24.1

Amol Grover

author

2020-01-10 12:45 UTC #1 lore raw

PATCH 2/3 drivers: target: target_core_tpg: Pass lockdep expression to RCU lists

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 <[email protected]>

---
 drivers/target/target_core_tpg.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

drivers/target/target_core_tpg.c +6 -3

index d24e0a3ba3ff..bc1c5dda81bf 100644
@@ -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;

Signature · 1 line

2.24.1

Amol Grover

author

2020-01-10 12:45 UTC #2 lore raw

PATCH 3/3 drivers: target: tcm_fc: tfc_sess: Pass lockdep expression to RCU lists

In reply to Amol Grover

head is traversed with hlist_for_each_entry_rcu outside an RCU read-side critical section but under the protection of ft_lport_lock.

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 <[email protected]>

---
 drivers/target/tcm_fc/tfc_sess.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

drivers/target/tcm_fc/tfc_sess.c +9 -6

index 4fd6a1de947c..8e9598010fb9 100644
@@ -32,6 +32,9 @@
 		 (lport)->host->host_no,	   \
 		 (lport)->port_id, ##args )
 
+#define ft_lport_lock_held() \
+	lockdep_is_held(&ft_lport_lock)
+
 static void ft_sess_delete_all(struct ft_tport *);
 
 /*

@@ -45,7 +48,7 @@ static struct ft_tport *ft_tport_get(struct fc_lport *lport)
 	int i;
 
 	tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
-					  lockdep_is_held(&ft_lport_lock));
+							ft_lport_lock_held());
 	if (tport && tport->tpg)
 		return tport;

@@ -170,7 +173,7 @@ static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
 	}
 
 	head = &tport->hash[ft_sess_hash(port_id)];
-	hlist_for_each_entry_rcu(sess, head, hash) {
+	hlist_for_each_entry_rcu(sess, head, hash, ft_lport_lock_held()) {
 		if (sess->port_id == port_id) {
 			kref_get(&sess->kref);
 			rcu_read_unlock();

@@ -215,7 +218,7 @@ static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
 	ft_format_wwn(&initiatorname[0], TRANSPORT_IQN_LEN, rdata->ids.port_name);
 
 	head = &tport->hash[ft_sess_hash(port_id)];
-	hlist_for_each_entry_rcu(sess, head, hash)
+	hlist_for_each_entry_rcu(sess, head, hash, ft_lport_lock_held())
 		if (sess->port_id == port_id)
 			return sess;

@@ -264,7 +267,7 @@ static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 	struct ft_sess *sess;
 
 	head = &tport->hash[ft_sess_hash(port_id)];
-	hlist_for_each_entry_rcu(sess, head, hash) {
+	hlist_for_each_entry_rcu(sess, head, hash, ft_lport_lock_held()) {
 		if (sess->port_id == port_id) {
 			ft_sess_unhash(sess);
 			return sess;

@@ -291,7 +294,7 @@ static void ft_sess_delete_all(struct ft_tport *tport)
 
 	for (head = tport->hash;
 	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
-		hlist_for_each_entry_rcu(sess, head, hash) {
+		hlist_for_each_entry_rcu(sess, head, hash, ft_lport_lock_held()) {
 			ft_sess_unhash(sess);
 			ft_close_sess(sess);	/* release from table */
 		}

@@ -454,7 +457,7 @@ static void ft_prlo(struct fc_rport_priv *rdata)
 
 	mutex_lock(&ft_lport_lock);
 	tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
-					  lockdep_is_held(&ft_lport_lock));
+							ft_lport_lock_held());
 
 	if (!tport) {
 		mutex_unlock(&ft_lport_lock);

Signature · 1 line

2.24.1