2020-01-10 17:08:16

by Amol Grover

[permalink] [raw]
Subject: [PATCH v2 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]>
---
v2:
- Fix sparse error
CHECK: Alignment should match open parenthesis

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

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 2d19f0e332b0..7627583e2509 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -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;
--
2.24.1


2020-01-10 17:09:04

by Amol Grover

[permalink] [raw]
Subject: [PATCH v2 3/3] drivers: target: tcm_fc: tfc_sess: Pass lockdep expression to RCU lists

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(-)

diff --git a/drivers/target/tcm_fc/tfc_sess.c b/drivers/target/tcm_fc/tfc_sess.c
index 4fd6a1de947c..8e9598010fb9 100644
--- a/drivers/target/tcm_fc/tfc_sess.c
+++ b/drivers/target/tcm_fc/tfc_sess.c
@@ -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);
--
2.24.1

2020-01-10 17:09:23

by Amol Grover

[permalink] [raw]
Subject: [PATCH v2 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(-)

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index d24e0a3ba3ff..0d89b738ca6e 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