1 files changed, 174 insertions, 101 deletions

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 4cf3ef4ddec3..988d0e37f87f 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -536,9 +536,27 @@ struct ipmi_smi {
 	unsigned int     waiting_events_count; /* How many events in queue? */
 	char             delivering_events;
 	char             event_msg_printed;
+
+	/* How many users are waiting for events? */
 	atomic_t         event_waiters;
 	unsigned int     ticks_to_req_ev;
-	int              last_needs_timer;
+
+	spinlock_t       watch_lock; /* For dealing with watch stuff below. */
+
+	/* How many users are waiting for commands? */
+	unsigned int     command_waiters;
+
+	/* How many users are waiting for watchdogs? */
+	unsigned int     watchdog_waiters;
+
+	/* How many users are waiting for message responses? */
+	unsigned int     response_waiters;
+
+	/*
+	 * Tells what the lower layer has last been asked to watch for,
+	 * messages and/or watchdogs.  Protected by watch_lock.
+	 */
+	unsigned int     last_watch_mask;
 
 	/*
 	 * The event receiver for my BMC, only really used at panic
@@ -932,6 +950,64 @@ static void deliver_err_response(struct ipmi_smi *intf,
 	deliver_local_response(intf, msg);
 }
 
+static void smi_add_watch(struct ipmi_smi *intf, unsigned int flags)
+{
+	unsigned long iflags;
+
+	if (!intf->handlers->set_need_watch)
+		return;
+
+	spin_lock_irqsave(&intf->watch_lock, iflags);
+	if (flags & IPMI_WATCH_MASK_CHECK_MESSAGES)
+		intf->response_waiters++;
+
+	if (flags & IPMI_WATCH_MASK_CHECK_WATCHDOG)
+		intf->watchdog_waiters++;
+
+	if (flags & IPMI_WATCH_MASK_CHECK_COMMANDS)
+		intf->command_waiters++;
+
+	if ((intf->last_watch_mask & flags) != flags) {
+		intf->last_watch_mask |= flags;
+		intf->handlers->set_need_watch(intf->send_info,
+					       intf->last_watch_mask);
+	}
+	spin_unlock_irqrestore(&intf->watch_lock, iflags);
+}
+
+static void smi_remove_watch(struct ipmi_smi *intf, unsigned int flags)
+{
+	unsigned long iflags;
+
+	if (!intf->handlers->set_need_watch)
+		return;
+
+	spin_lock_irqsave(&intf->watch_lock, iflags);
+	if (flags & IPMI_WATCH_MASK_CHECK_MESSAGES)
+		intf->response_waiters--;
+
+	if (flags & IPMI_WATCH_MASK_CHECK_WATCHDOG)
+		intf->watchdog_waiters--;
+
+	if (flags & IPMI_WATCH_MASK_CHECK_COMMANDS)
+		intf->command_waiters--;
+
+	flags = 0;
+	if (intf->response_waiters)
+		flags |= IPMI_WATCH_MASK_CHECK_MESSAGES;
+	if (intf->watchdog_waiters)
+		flags |= IPMI_WATCH_MASK_CHECK_WATCHDOG;
+	if (intf->command_waiters)
+		flags |= IPMI_WATCH_MASK_CHECK_COMMANDS;
+
+	if (intf->last_watch_mask != flags) {
+		intf->last_watch_mask = flags;
+		intf->handlers->set_need_watch(intf->send_info,
+					       intf->last_watch_mask);
+	}
+	spin_unlock_irqrestore(&intf->watch_lock, iflags);
+}
+
 /*
  * Find the next sequence number not being used and add the given
  * message with the given timeout to the sequence table.  This must be
@@ -975,6 +1051,7 @@ static int intf_next_seq(struct ipmi_smi      *intf,
 		*seq = i;
 		*seqid = intf->seq_table[i].seqid;
 		intf->curr_seq = (i+1)%IPMI_IPMB_NUM_SEQ;
+		smi_add_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
 		need_waiter(intf);
 	} else {
 		rv = -EAGAIN;
@@ -1013,6 +1090,7 @@ static int intf_find_seq(struct ipmi_smi      *intf,
 				&& (ipmi_addr_equal(addr, &msg->addr))) {
 			*recv_msg = msg;
 			intf->seq_table[seq].inuse = 0;
+			smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
 			rv = 0;
 		}
 	}
@@ -1074,6 +1152,7 @@ static int intf_err_seq(struct ipmi_smi *intf,
 		struct seq_table *ent = &intf->seq_table[seq];
 
 		ent->inuse = 0;
+		smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
 		msg = ent->recv_msg;
 		rv = 0;
 	}
@@ -1085,7 +1164,6 @@ static int intf_err_seq(struct ipmi_smi *intf,
 	return rv;
 }
 
-
 static void free_user_work(struct work_struct *work)
 {
 	struct ipmi_user *user = container_of(work, struct ipmi_user,
@@ -1162,11 +1240,9 @@ int ipmi_create_user(unsigned int          if_num,
 	spin_lock_irqsave(&intf->seq_lock, flags);
 	list_add_rcu(&new_user->link, &intf->users);
 	spin_unlock_irqrestore(&intf->seq_lock, flags);
-	if (handler->ipmi_watchdog_pretimeout) {
+	if (handler->ipmi_watchdog_pretimeout)
 		/* User wants pretimeouts, so make sure to watch for them. */
-		if (atomic_inc_return(&intf->event_waiters) == 1)
-			need_waiter(intf);
-	}
+		smi_add_watch(intf, IPMI_WATCH_MASK_CHECK_WATCHDOG);
 	srcu_read_unlock(&ipmi_interfaces_srcu, index);
 	*user = new_user;
 	return 0;
@@ -1219,6 +1295,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
 	unsigned long    flags;
 	struct cmd_rcvr  *rcvr;
 	struct cmd_rcvr  *rcvrs = NULL;
+	struct module    *owner;
 
 	if (!acquire_ipmi_user(user, &i)) {
 		/*
@@ -1238,7 +1315,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
 		user->handler->shutdown(user->handler_data);
 
 	if (user->handler->ipmi_watchdog_pretimeout)
-		atomic_dec(&intf->event_waiters);
+		smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_WATCHDOG);
 
 	if (user->gets_events)
 		atomic_dec(&intf->event_waiters);
@@ -1251,6 +1328,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
 		if (intf->seq_table[i].inuse
 		    && (intf->seq_table[i].recv_msg->user == user)) {
 			intf->seq_table[i].inuse = 0;
+			smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
 			ipmi_free_recv_msg(intf->seq_table[i].recv_msg);
 		}
 	}
@@ -1278,8 +1356,9 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
 		kfree(rcvr);
 	}
 
+	owner = intf->owner;
 	kref_put(&intf->refcount, intf_free);
-	module_put(intf->owner);
+	module_put(owner);
 }
 
 int ipmi_destroy_user(struct ipmi_user *user)
@@ -1595,8 +1674,7 @@ int ipmi_register_for_cmd(struct ipmi_user *user,
 		goto out_unlock;
 	}
 
-	if (atomic_inc_return(&intf->event_waiters) == 1)
-		need_waiter(intf);
+	smi_add_watch(intf, IPMI_WATCH_MASK_CHECK_COMMANDS);
 
 	list_add_rcu(&rcvr->link, &intf->cmd_rcvrs);
 
@@ -1646,7 +1724,7 @@ int ipmi_unregister_for_cmd(struct ipmi_user *user,
 	synchronize_rcu();
 	release_ipmi_user(user, index);
 	while (rcvrs) {
-		atomic_dec(&intf->event_waiters);
+		smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_COMMANDS);
 		rcvr = rcvrs;
 		rcvrs = rcvr->next;
 		kfree(rcvr);
@@ -1763,22 +1841,19 @@ static struct ipmi_smi_msg *smi_add_send_msg(struct ipmi_smi *intf,
 	return smi_msg;
 }
 
-
 static void smi_send(struct ipmi_smi *intf,
 		     const struct ipmi_smi_handlers *handlers,
 		     struct ipmi_smi_msg *smi_msg, int priority)
 {
 	int run_to_completion = intf->run_to_completion;
+	unsigned long flags = 0;
 
-	if (run_to_completion) {
-		smi_msg = smi_add_send_msg(intf, smi_msg, priority);
-	} else {
-		unsigned long flags;
-
+	if (!run_to_completion)
 		spin_lock_irqsave(&intf->xmit_msgs_lock, flags);
-		smi_msg = smi_add_send_msg(intf, smi_msg, priority);
+	smi_msg = smi_add_send_msg(intf, smi_msg, priority);
+
+	if (!run_to_completion)
 		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
-	}
 
 	if (smi_msg)
 		handlers->sender(intf->send_info, smi_msg);
@@ -3383,6 +3458,7 @@ int ipmi_add_smi(struct module         *owner,
 	INIT_LIST_HEAD(&intf->xmit_msgs);
 	INIT_LIST_HEAD(&intf->hp_xmit_msgs);
 	spin_lock_init(&intf->events_lock);
+	spin_lock_init(&intf->watch_lock);
 	atomic_set(&intf->event_waiters, 0);
 	intf->ticks_to_req_ev = IPMI_REQUEST_EV_TIME;
 	INIT_LIST_HEAD(&intf->waiting_events);
@@ -3461,12 +3537,16 @@ static void deliver_smi_err_response(struct ipmi_smi *intf,
 				     struct ipmi_smi_msg *msg,
 				     unsigned char err)
 {
+	int rv;
 	msg->rsp[0] = msg->data[0] | 4;
 	msg->rsp[1] = msg->data[1];
 	msg->rsp[2] = err;
 	msg->rsp_size = 3;
-	/* It's an error, so it will never requeue, no need to check return. */
-	handle_one_recv_msg(intf, msg);
+
+	/* This will never requeue, but it may ask us to free the message. */
+	rv = handle_one_recv_msg(intf, msg);
+	if (rv == 0)
+		ipmi_free_smi_msg(msg);
 }
 
 static void cleanup_smi_msgs(struct ipmi_smi *intf)
@@ -4159,7 +4239,53 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
 	int chan;
 
 	ipmi_debug_msg("Recv:", msg->rsp, msg->rsp_size);
-	if (msg->rsp_size < 2) {
+
+	if ((msg->data_size >= 2)
+	    && (msg->data[0] == (IPMI_NETFN_APP_REQUEST << 2))
+	    && (msg->data[1] == IPMI_SEND_MSG_CMD)
+	    && (msg->user_data == NULL)) {
+
+		if (intf->in_shutdown)
+			goto free_msg;
+
+		/*
+		 * This is the local response to a command send, start
+		 * the timer for these.  The user_data will not be
+		 * NULL if this is a response send, and we will let
+		 * response sends just go through.
+		 */
+
+		/*
+		 * Check for errors, if we get certain errors (ones
+		 * that mean basically we can try again later), we
+		 * ignore them and start the timer.  Otherwise we
+		 * report the error immediately.
+		 */
+		if ((msg->rsp_size >= 3) && (msg->rsp[2] != 0)
+		    && (msg->rsp[2] != IPMI_NODE_BUSY_ERR)
+		    && (msg->rsp[2] != IPMI_LOST_ARBITRATION_ERR)
+		    && (msg->rsp[2] != IPMI_BUS_ERR)
+		    && (msg->rsp[2] != IPMI_NAK_ON_WRITE_ERR)) {
+			int ch = msg->rsp[3] & 0xf;
+			struct ipmi_channel *chans;
+
+			/* Got an error sending the message, handle it. */
+
+			chans = READ_ONCE(intf->channel_list)->c;
+			if ((chans[ch].medium == IPMI_CHANNEL_MEDIUM_8023LAN)
+			    || (chans[ch].medium == IPMI_CHANNEL_MEDIUM_ASYNC))
+				ipmi_inc_stat(intf, sent_lan_command_errs);
+			else
+				ipmi_inc_stat(intf, sent_ipmb_command_errs);
+			intf_err_seq(intf, msg->msgid, msg->rsp[2]);
+		} else
+			/* The message was sent, start the timer. */
+			intf_start_seq_timer(intf, msg->msgid);
+free_msg:
+		requeue = 0;
+		goto out;
+
+	} else if (msg->rsp_size < 2) {
 		/* Message is too small to be correct. */
 		dev_warn(intf->si_dev,
 			 PFX "BMC returned to small a message for netfn %x cmd %x, got %d bytes\n",
@@ -4398,6 +4524,7 @@ static void smi_recv_tasklet(unsigned long val)
 			intf->curr_msg = newmsg;
 		}
 	}
+
 	if (!run_to_completion)
 		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
 	if (newmsg)
@@ -4415,62 +4542,16 @@ void ipmi_smi_msg_received(struct ipmi_smi *intf,
 	unsigned long flags = 0; /* keep us warning-free. */
 	int run_to_completion = intf->run_to_completion;
 
-	if ((msg->data_size >= 2)
-	    && (msg->data[0] == (IPMI_NETFN_APP_REQUEST << 2))
-	    && (msg->data[1] == IPMI_SEND_MSG_CMD)
-	    && (msg->user_data == NULL)) {
-
-		if (intf->in_shutdown)
-			goto free_msg;
-
-		/*
-		 * This is the local response to a command send, start
-		 * the timer for these.  The user_data will not be
-		 * NULL if this is a response send, and we will let
-		 * response sends just go through.
-		 */
-
-		/*
-		 * Check for errors, if we get certain errors (ones
-		 * that mean basically we can try again later), we
-		 * ignore them and start the timer.  Otherwise we
-		 * report the error immediately.
-		 */
-		if ((msg->rsp_size >= 3) && (msg->rsp[2] != 0)
-		    && (msg->rsp[2] != IPMI_NODE_BUSY_ERR)
-		    && (msg->rsp[2] != IPMI_LOST_ARBITRATION_ERR)
-		    && (msg->rsp[2] != IPMI_BUS_ERR)
-		    && (msg->rsp[2] != IPMI_NAK_ON_WRITE_ERR)) {
-			int ch = msg->rsp[3] & 0xf;
-			struct ipmi_channel *chans;
-
-			/* Got an error sending the message, handle it. */
-
-			chans = READ_ONCE(intf->channel_list)->c;
-			if ((chans[ch].medium == IPMI_CHANNEL_MEDIUM_8023LAN)
-			    || (chans[ch].medium == IPMI_CHANNEL_MEDIUM_ASYNC))
-				ipmi_inc_stat(intf, sent_lan_command_errs);
-			else
-				ipmi_inc_stat(intf, sent_ipmb_command_errs);
-			intf_err_seq(intf, msg->msgid, msg->rsp[2]);
-		} else
-			/* The message was sent, start the timer. */
-			intf_start_seq_timer(intf, msg->msgid);
-
-free_msg:
-		ipmi_free_smi_msg(msg);
-	} else {
-		/*
-		 * To preserve message order, we keep a queue and deliver from
-		 * a tasklet.
-		 */
-		if (!run_to_completion)
-			spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
-		list_add_tail(&msg->link, &intf->waiting_rcv_msgs);
-		if (!run_to_completion)
-			spin_unlock_irqrestore(&intf->waiting_rcv_msgs_lock,
-					       flags);
-	}
+	/*
+	 * To preserve message order, we keep a queue and deliver from
+	 * a tasklet.
+	 */
+	if (!run_to_completion)
+		spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
+	list_add_tail(&msg->link, &intf->waiting_rcv_msgs);
+	if (!run_to_completion)
+		spin_unlock_irqrestore(&intf->waiting_rcv_msgs_lock,
+				       flags);
 
 	if (!run_to_completion)
 		spin_lock_irqsave(&intf->xmit_msgs_lock, flags);
@@ -4525,7 +4606,7 @@ static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
 			      struct list_head *timeouts,
 			      unsigned long timeout_period,
 			      int slot, unsigned long *flags,
-			      unsigned int *waiting_msgs)
+			      bool *need_timer)
 {
 	struct ipmi_recv_msg *msg;
 
@@ -4537,13 +4618,14 @@ static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
 
 	if (timeout_period < ent->timeout) {
 		ent->timeout -= timeout_period;
-		(*waiting_msgs)++;
+		*need_timer = true;
 		return;
 	}
 
 	if (ent->retries_left == 0) {
 		/* The message has used all its retries. */
 		ent->inuse = 0;
+		smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
 		msg = ent->recv_msg;
 		list_add_tail(&msg->link, timeouts);
 		if (ent->broadcast)
@@ -4556,7 +4638,7 @@ static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
 		struct ipmi_smi_msg *smi_msg;
 		/* More retries, send again. */
 
-		(*waiting_msgs)++;
+		*need_timer = true;
 
 		/*
 		 * Start with the max timer, set to normal timer after
@@ -4601,20 +4683,20 @@ static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
 	}
 }
 
-static unsigned int ipmi_timeout_handler(struct ipmi_smi *intf,
-					 unsigned long timeout_period)
+static bool ipmi_timeout_handler(struct ipmi_smi *intf,
+				 unsigned long timeout_period)
 {
 	struct list_head     timeouts;
 	struct ipmi_recv_msg *msg, *msg2;
 	unsigned long        flags;
 	int                  i;
-	unsigned int         waiting_msgs = 0;
+	bool                 need_timer = false;
 
 	if (!intf->bmc_registered) {
 		kref_get(&intf->refcount);
 		if (!schedule_work(&intf->bmc_reg_work)) {
 			kref_put(&intf->refcount, intf_free);
-			waiting_msgs++;
+			need_timer = true;
 		}
 	}
 
@@ -4634,7 +4716,7 @@ static unsigned int ipmi_timeout_handler(struct ipmi_smi *intf,
 	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++)
 		check_msg_timeout(intf, &intf->seq_table[i],
 				  &timeouts, timeout_period, i,
-				  &flags, &waiting_msgs);
+				  &flags, &need_timer);
 	spin_unlock_irqrestore(&intf->seq_lock, flags);
 
 	list_for_each_entry_safe(msg, msg2, &timeouts, link)
@@ -4665,7 +4747,7 @@ static unsigned int ipmi_timeout_handler(struct ipmi_smi *intf,
 
 	tasklet_schedule(&intf->recv_tasklet);
 
-	return waiting_msgs;
+	return need_timer;
 }
 
 static void ipmi_request_event(struct ipmi_smi *intf)
@@ -4685,37 +4767,28 @@ static atomic_t stop_operation;
 static void ipmi_timeout(struct timer_list *unused)
 {
 	struct ipmi_smi *intf;
-	int nt = 0, index;
+	bool need_timer = false;
+	int index;
 
 	if (atomic_read(&stop_operation))
 		return;
 
 	index = srcu_read_lock(&ipmi_interfaces_srcu);
 	list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
-		int lnt = 0;
-
 		if (atomic_read(&intf->event_waiters)) {
 			intf->ticks_to_req_ev--;
 			if (intf->ticks_to_req_ev == 0) {
 				ipmi_request_event(intf);
 				intf->ticks_to_req_ev = IPMI_REQUEST_EV_TIME;
 			}
-			lnt++;
+			need_timer = true;
 		}
 
-		lnt += ipmi_timeout_handler(intf, IPMI_TIMEOUT_TIME);
-
-		lnt = !!lnt;
-		if (lnt != intf->last_needs_timer &&
-					intf->handlers->set_need_watch)
-			intf->handlers->set_need_watch(intf->send_info, lnt);
-		intf->last_needs_timer = lnt;
-
-		nt += lnt;
+		need_timer |= ipmi_timeout_handler(intf, IPMI_TIMEOUT_TIME);
 	}
 	srcu_read_unlock(&ipmi_interfaces_srcu, index);
 
-	if (nt)
+	if (need_timer)
 		mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
 }