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Commit e61fb5b6 authored by Corey Minyard's avatar Corey Minyard Committed by Linus Torvalds
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[PATCH] ipmi: use rcu lock for using command receivers 



Use rcu_read_lock for the cmd_rcvrs list, since that was what what
intended, anyway.  This means that all the users of the cmd_rcvrs_lock are
tasks, so the irq disables are no longer required for that lock and it can
become a semaphore.

Signed-off-by: default avatarCorey Minyard <minyard@acm.org>
Acked-by: default avatar"Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent e9a705a0

drivers/char/ipmi/ipmi_msghandler.c

+15 −16
Original line number Original line Diff line number Diff line
@@ -209,7 +209,7 @@ struct ipmi_smi 




	/* The list of command receivers that are registered for commands

	/* The list of command receivers that are registered for commands

	   on this interface. */

	   on this interface. */

	spinlock_t       cmd_rcvrs_lock;

	struct semaphore cmd_rcvrs_lock;

	struct list_head cmd_rcvrs;

	struct list_head cmd_rcvrs;





	/* Events that were queues because no one was there to receive

	/* Events that were queues because no one was there to receive
@@ -345,7 +345,6 @@ static void clean_up_interface_data(ipmi_smi_t intf) 
{

{

	int              i;

	int              i;

	struct cmd_rcvr  *rcvr, *rcvr2;

	struct cmd_rcvr  *rcvr, *rcvr2;

	unsigned long    flags;

	struct list_head list;

	struct list_head list;





	free_recv_msg_list(&intf->waiting_msgs);

	free_recv_msg_list(&intf->waiting_msgs);
@@ -353,10 +352,10 @@ static void clean_up_interface_data(ipmi_smi_t intf) 




	/* Wholesale remove all the entries from the list in the

	/* Wholesale remove all the entries from the list in the

	 * interface and wait for RCU to know that none are in use. */

	 * interface and wait for RCU to know that none are in use. */

	spin_lock_irqsave(&intf->cmd_rcvrs_lock, flags);

	down(&intf->cmd_rcvrs_lock);

	list_add_rcu(&list, &intf->cmd_rcvrs);

	list_add_rcu(&list, &intf->cmd_rcvrs);

	list_del_rcu(&intf->cmd_rcvrs);

	list_del_rcu(&intf->cmd_rcvrs);

	spin_unlock_irqrestore(&intf->cmd_rcvrs_lock, flags);

	up(&intf->cmd_rcvrs_lock);

	synchronize_rcu();

	synchronize_rcu();





	list_for_each_entry_safe(rcvr, rcvr2, &list, link)

	list_for_each_entry_safe(rcvr, rcvr2, &list, link)
@@ -812,7 +811,7 @@ int ipmi_destroy_user(ipmi_user_t user) 
	 * since other things may be using it till we do

	 * since other things may be using it till we do

	 * synchronize_rcu()) then free everything in that list.

	 * synchronize_rcu()) then free everything in that list.

	 */

	 */

	spin_lock_irqsave(&intf->cmd_rcvrs_lock, flags);

	down(&intf->cmd_rcvrs_lock);

	list_for_each_safe_rcu(entry1, entry2, &intf->cmd_rcvrs) {

	list_for_each_safe_rcu(entry1, entry2, &intf->cmd_rcvrs) {

		rcvr = list_entry(entry1, struct cmd_rcvr, link);

		rcvr = list_entry(entry1, struct cmd_rcvr, link);

		if (rcvr->user == user) {

		if (rcvr->user == user) {
@@ -821,7 +820,7 @@ int ipmi_destroy_user(ipmi_user_t user) 
			rcvrs = rcvr;

			rcvrs = rcvr;

		}

		}

	}

	}

	spin_unlock_irqrestore(&intf->cmd_rcvrs_lock, flags);

	up(&intf->cmd_rcvrs_lock);

	synchronize_rcu();

	synchronize_rcu();

	while (rcvrs) {

	while (rcvrs) {

		rcvr = rcvrs;

		rcvr = rcvrs;
@@ -950,7 +949,7 @@ int ipmi_register_for_cmd(ipmi_user_t user, 
	rcvr->netfn = netfn;

	rcvr->netfn = netfn;

	rcvr->user = user;

	rcvr->user = user;





	spin_lock_irq(&intf->cmd_rcvrs_lock);

	down(&intf->cmd_rcvrs_lock);

	/* Make sure the command/netfn is not already registered. */

	/* Make sure the command/netfn is not already registered. */

	entry = find_cmd_rcvr(intf, netfn, cmd);

	entry = find_cmd_rcvr(intf, netfn, cmd);

	if (entry) {

	if (entry) {
@@ -961,7 +960,7 @@ int ipmi_register_for_cmd(ipmi_user_t user, 
	list_add_rcu(&rcvr->link, &intf->cmd_rcvrs);

	list_add_rcu(&rcvr->link, &intf->cmd_rcvrs);





 out_unlock:

 out_unlock:

	spin_unlock_irq(&intf->cmd_rcvrs_lock);

	up(&intf->cmd_rcvrs_lock);

	if (rv)

	if (rv)

		kfree(rcvr);

		kfree(rcvr);
@@ -975,17 +974,17 @@ int ipmi_unregister_for_cmd(ipmi_user_t user, 
	ipmi_smi_t      intf = user->intf;

	ipmi_smi_t      intf = user->intf;

	struct cmd_rcvr *rcvr;

	struct cmd_rcvr *rcvr;





	spin_lock_irq(&intf->cmd_rcvrs_lock);

	down(&intf->cmd_rcvrs_lock);

	/* Make sure the command/netfn is not already registered. */

	/* Make sure the command/netfn is not already registered. */

	rcvr = find_cmd_rcvr(intf, netfn, cmd);

	rcvr = find_cmd_rcvr(intf, netfn, cmd);

	if ((rcvr) && (rcvr->user == user)) {

	if ((rcvr) && (rcvr->user == user)) {

		list_del_rcu(&rcvr->link);

		list_del_rcu(&rcvr->link);

		spin_unlock_irq(&intf->cmd_rcvrs_lock);

		up(&intf->cmd_rcvrs_lock);

		synchronize_rcu();

		synchronize_rcu();

		kfree(rcvr);

		kfree(rcvr);

		return 0;

		return 0;

	} else {

	} else {

		spin_unlock_irq(&intf->cmd_rcvrs_lock);

		up(&intf->cmd_rcvrs_lock);

		return -ENOENT;

		return -ENOENT;

	}

	}

}

}
@@ -1858,7 +1857,7 @@ int ipmi_register_smi(struct ipmi_smi_handlers *handlers, 
	spin_lock_init(&intf->events_lock);

	spin_lock_init(&intf->events_lock);

	INIT_LIST_HEAD(&intf->waiting_events);

	INIT_LIST_HEAD(&intf->waiting_events);

	intf->waiting_events_count = 0;

	intf->waiting_events_count = 0;

	spin_lock_init(&intf->cmd_rcvrs_lock);

	init_MUTEX(&intf->cmd_rcvrs_lock);

	INIT_LIST_HEAD(&intf->cmd_rcvrs);

	INIT_LIST_HEAD(&intf->cmd_rcvrs);

	init_waitqueue_head(&intf->waitq);

	init_waitqueue_head(&intf->waitq);
@@ -2058,14 +2057,14 @@ static int handle_ipmb_get_msg_cmd(ipmi_smi_t intf, 
	netfn = msg->rsp[4] >> 2;

	netfn = msg->rsp[4] >> 2;

	cmd = msg->rsp[8];

	cmd = msg->rsp[8];





	spin_lock_irqsave(&intf->cmd_rcvrs_lock, flags);

	rcu_read_lock();

	rcvr = find_cmd_rcvr(intf, netfn, cmd);

	rcvr = find_cmd_rcvr(intf, netfn, cmd);

	if (rcvr) {

	if (rcvr) {

		user = rcvr->user;

		user = rcvr->user;

		kref_get(&user->refcount);

		kref_get(&user->refcount);

	} else

	} else

		user = NULL;

		user = NULL;

	spin_unlock_irqrestore(&intf->cmd_rcvrs_lock, flags);

	rcu_read_unlock();





	if (user == NULL) {

	if (user == NULL) {

		/* We didn't find a user, deliver an error response. */

		/* We didn't find a user, deliver an error response. */
@@ -2238,14 +2237,14 @@ static int handle_lan_get_msg_cmd(ipmi_smi_t intf, 
	netfn = msg->rsp[6] >> 2;

	netfn = msg->rsp[6] >> 2;

	cmd = msg->rsp[10];

	cmd = msg->rsp[10];





	spin_lock_irqsave(&intf->cmd_rcvrs_lock, flags);

	rcu_read_lock();

	rcvr = find_cmd_rcvr(intf, netfn, cmd);

	rcvr = find_cmd_rcvr(intf, netfn, cmd);

	if (rcvr) {

	if (rcvr) {

		user = rcvr->user;

		user = rcvr->user;

		kref_get(&user->refcount);

		kref_get(&user->refcount);

	} else

	} else

		user = NULL;

		user = NULL;

	spin_unlock_irqrestore(&intf->cmd_rcvrs_lock, flags);

	rcu_read_unlock();





	if (user == NULL) {

	if (user == NULL) {

		/* We didn't find a user, just give up. */

		/* We didn't find a user, just give up. */