Commit 4f1885a7 authored by Amol Grover's avatar Amol Grover Committed by Corey Minyard
Browse files

drivers: char: ipmi: ipmi_msghandler: Pass lockdep expression to RCU lists 



intf->cmd_rcvrs is traversed with list_for_each_entry_rcu
outside an RCU read-side critical section but under the
protection of intf->cmd_rcvrs_mutex.

ipmi_interfaces is traversed using list_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of ipmi_interfaces_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: default avatarAmol Grover <frextrite@gmail.com>
Message-Id: <20200117132521.31020-1-frextrite@gmail.com>
Acked-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Tested-by: default avatarJohn Garry <john.garry@huawei.com>
Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
parent 3cc6e2c5

drivers/char/ipmi/ipmi_msghandler.c

+10 −4
Original line number Diff line number Diff line
@@ -618,6 +618,8 @@ static DEFINE_MUTEX(ipmidriver_mutex); 


static LIST_HEAD(ipmi_interfaces);

static DEFINE_MUTEX(ipmi_interfaces_mutex);

#define ipmi_interfaces_mutex_held() \

	lockdep_is_held(&ipmi_interfaces_mutex)

static struct srcu_struct ipmi_interfaces_srcu;



/*
@@ -1321,7 +1323,8 @@ static void _ipmi_destroy_user(struct ipmi_user *user) 
	 * synchronize_srcu()) then free everything in that list.

	 */

	mutex_lock(&intf->cmd_rcvrs_mutex);

	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {

	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link,

				lockdep_is_held(&intf->cmd_rcvrs_mutex)) {

		if (rcvr->user == user) {

			list_del_rcu(&rcvr->link);

			rcvr->next = rcvrs;
@@ -1599,7 +1602,8 @@ static struct cmd_rcvr *find_cmd_rcvr(struct ipmi_smi *intf, 
{

	struct cmd_rcvr *rcvr;



	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {

	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link,

				lockdep_is_held(&intf->cmd_rcvrs_mutex)) {

		if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd)

					&& (rcvr->chans & (1 << chan)))

			return rcvr;
@@ -1614,7 +1618,8 @@ static int is_cmd_rcvr_exclusive(struct ipmi_smi *intf, 
{

	struct cmd_rcvr *rcvr;



	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {

	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link,

				lockdep_is_held(&intf->cmd_rcvrs_mutex)) {

		if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd)

					&& (rcvr->chans & chans))

			return 0;
@@ -3450,7 +3455,8 @@ int ipmi_add_smi(struct module *owner, 
	/* Look for a hole in the numbers. */

	i = 0;

	link = &ipmi_interfaces;

	list_for_each_entry_rcu(tintf, &ipmi_interfaces, link) {

	list_for_each_entry_rcu(tintf, &ipmi_interfaces, link,

				ipmi_interfaces_mutex_held()) {

		if (tintf->intf_num != i) {

			link = &tintf->link;

			break;

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