Commit 557602f2 authored by Corey Minyard's avatar Corey Minyard
Browse files

ipmi:msghandler: Deliver user messages in a work queue 



This simplifies the locking and lets us remove some weird event
handling code.  deliver_response() and friends can now be called
from an atomic context.

Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
parent 74221986

drivers/char/ipmi/ipmi_msghandler.c

+25 −16
Original line number Diff line number Diff line
@@ -495,6 +495,12 @@ struct ipmi_smi { 
	struct seq_table seq_table[IPMI_IPMB_NUM_SEQ];

	int curr_seq;



	/*

	 * Messages queued for deliver to the user.

	 */

	struct mutex user_msgs_mutex;

	struct list_head user_msgs;



	/*

	 * Messages queued for delivery.  If delivery fails (out of memory

	 * for instance), They will stay in here to be processed later in a
@@ -525,7 +531,6 @@ struct ipmi_smi { 
	spinlock_t       events_lock; /* For dealing with event stuff. */

	struct list_head waiting_events;

	unsigned int     waiting_events_count; /* How many events in queue? */

	char             delivering_events;

	char             event_msg_printed;



	/* How many users are waiting for events? */
@@ -945,9 +950,13 @@ static int deliver_response(struct ipmi_smi *intf, struct ipmi_recv_msg *msg) 
		struct ipmi_user *user = acquire_ipmi_user(msg->user, &index);



		if (user) {

			atomic_dec(&user->nr_msgs);

			user->handler->ipmi_recv_hndl(msg, user->handler_data);

			/* Deliver it in smi_work. */

			kref_get(&user->refcount);

			mutex_lock(&intf->user_msgs_mutex);

			list_add_tail(&msg->link, &intf->user_msgs);

			mutex_unlock(&intf->user_msgs_mutex);

			release_ipmi_user(user, index);

			queue_work(system_bh_wq, &intf->smi_work);

		} else {

			/* User went away, give up. */

			ipmi_free_recv_msg(msg);
@@ -1610,13 +1619,6 @@ int ipmi_set_gets_events(struct ipmi_user *user, bool val) 
		atomic_dec(&intf->event_waiters);

	}



	if (intf->delivering_events)

		/*

		 * Another thread is delivering events for this, so

		 * let it handle any new events.

		 */

		goto out;



	/* Deliver any queued events. */

	while (user->gets_events && !list_empty(&intf->waiting_events)) {

		list_for_each_entry_safe(msg, msg2, &intf->waiting_events, link)
@@ -1627,17 +1629,11 @@ int ipmi_set_gets_events(struct ipmi_user *user, bool val) 
			intf->event_msg_printed = 0;

		}



		intf->delivering_events = 1;

		spin_unlock_irqrestore(&intf->events_lock, flags);



		list_for_each_entry_safe(msg, msg2, &msgs, link) {

			msg->user = user;

			kref_get(&user->refcount);

			deliver_local_response(intf, msg);

		}



		spin_lock_irqsave(&intf->events_lock, flags);

		intf->delivering_events = 0;

	}



 out:
@@ -3590,6 +3586,8 @@ int ipmi_add_smi(struct module *owner, 
	}

	if (slave_addr != 0)

		intf->addrinfo[0].address = slave_addr;

	INIT_LIST_HEAD(&intf->user_msgs);

	mutex_init(&intf->user_msgs_mutex);

	INIT_LIST_HEAD(&intf->users);

	atomic_set(&intf->nr_users, 0);

	intf->handlers = handlers;
@@ -4814,6 +4812,7 @@ static void smi_work(struct work_struct *t) 
	struct ipmi_smi *intf = from_work(intf, t, smi_work);

	int run_to_completion = READ_ONCE(intf->run_to_completion);

	struct ipmi_smi_msg *newmsg = NULL;

	struct ipmi_recv_msg *msg, *msg2;



	/*

	 * Start the next message if available.
@@ -4851,6 +4850,16 @@ static void smi_work(struct work_struct *t) 
	rcu_read_unlock();



	handle_new_recv_msgs(intf);



	mutex_lock(&intf->user_msgs_mutex);

	list_for_each_entry_safe(msg, msg2, &intf->user_msgs, link) {

		struct ipmi_user *user = msg->user;



		atomic_dec(&user->nr_msgs);

		user->handler->ipmi_recv_hndl(msg, user->handler_data);

		kref_put(&user->refcount, free_user);

	}

	mutex_unlock(&intf->user_msgs_mutex);

}



/* Handle a new message from the lower layer. */