ipmi: use a tasklet for handling received messages
The IPMI driver would release a lock, deliver a message, then relock. This is obviously ugly, and this patch converts the message handler interface to use a tasklet to schedule work. This lets the receive handler be called from an interrupt handler with interrupts enabled. Signed-off-by: Corey Minyard <cminyard@mvista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Corey Minyard
Linus Torvalds
Родитель
828dc9da50
Коммит
7adf579c8b
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@ -46,6 +46,7 @@
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#include <linux/init.h>
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#include <linux/proc_fs.h>
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#include <linux/rcupdate.h>
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#include <linux/interrupt.h>
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#define PFX "IPMI message handler: "
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@ -53,6 +54,8 @@
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static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
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static int ipmi_init_msghandler(void);
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static void smi_recv_tasklet(unsigned long);
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static void handle_new_recv_msgs(ipmi_smi_t intf);
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static int initialized;
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@ -355,12 +358,15 @@ struct ipmi_smi {
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int curr_seq;
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/*
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* Messages that were delayed for some reason (out of memory,
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* for instance), will go in here to be processed later in a
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* periodic timer interrupt.
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* Messages queued for delivery. If delivery fails (out of memory
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* for instance), They will stay in here to be processed later in a
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* periodic timer interrupt. The tasklet is for handling received
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* messages directly from the handler.
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*/
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spinlock_t waiting_msgs_lock;
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struct list_head waiting_msgs;
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atomic_t watchdog_pretimeouts_to_deliver;
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struct tasklet_struct recv_tasklet;
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/*
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* The list of command receivers that are registered for commands
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@ -493,6 +499,8 @@ static void clean_up_interface_data(ipmi_smi_t intf)
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struct cmd_rcvr *rcvr, *rcvr2;
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struct list_head list;
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tasklet_kill(&intf->recv_tasklet);
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free_smi_msg_list(&intf->waiting_msgs);
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free_recv_msg_list(&intf->waiting_events);
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@ -2792,6 +2800,9 @@ void ipmi_poll_interface(ipmi_user_t user)
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if (intf->handlers->poll)
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intf->handlers->poll(intf->send_info);
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/* In case something came in */
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handle_new_recv_msgs(intf);
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}
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EXPORT_SYMBOL(ipmi_poll_interface);
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@ -2860,6 +2871,10 @@ int ipmi_register_smi(struct ipmi_smi_handlers *handlers,
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#endif
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spin_lock_init(&intf->waiting_msgs_lock);
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INIT_LIST_HEAD(&intf->waiting_msgs);
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tasklet_init(&intf->recv_tasklet,
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smi_recv_tasklet,
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(unsigned long) intf);
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atomic_set(&intf->watchdog_pretimeouts_to_deliver, 0);
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spin_lock_init(&intf->events_lock);
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INIT_LIST_HEAD(&intf->waiting_events);
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intf->waiting_events_count = 0;
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@ -3622,11 +3637,11 @@ static int handle_bmc_rsp(ipmi_smi_t intf,
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}
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/*
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* Handle a new message. Return 1 if the message should be requeued,
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* Handle a received message. Return 1 if the message should be requeued,
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* 0 if the message should be freed, or -1 if the message should not
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* be freed or requeued.
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*/
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static int handle_new_recv_msg(ipmi_smi_t intf,
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static int handle_one_recv_msg(ipmi_smi_t intf,
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struct ipmi_smi_msg *msg)
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{
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int requeue;
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@ -3784,12 +3799,72 @@ static int handle_new_recv_msg(ipmi_smi_t intf,
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return requeue;
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}
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/*
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* If there are messages in the queue or pretimeouts, handle them.
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*/
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static void handle_new_recv_msgs(ipmi_smi_t intf)
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{
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struct ipmi_smi_msg *smi_msg;
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unsigned long flags = 0;
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int rv;
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int run_to_completion = intf->run_to_completion;
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/* See if any waiting messages need to be processed. */
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if (!run_to_completion)
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spin_lock_irqsave(&intf->waiting_msgs_lock, flags);
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while (!list_empty(&intf->waiting_msgs)) {
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smi_msg = list_entry(intf->waiting_msgs.next,
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struct ipmi_smi_msg, link);
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list_del(&smi_msg->link);
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if (!run_to_completion)
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spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);
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rv = handle_one_recv_msg(intf, smi_msg);
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if (!run_to_completion)
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spin_lock_irqsave(&intf->waiting_msgs_lock, flags);
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if (rv == 0) {
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/* Message handled */
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ipmi_free_smi_msg(smi_msg);
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} else if (rv < 0) {
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/* Fatal error on the message, del but don't free. */
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} else {
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/*
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* To preserve message order, quit if we
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* can't handle a message.
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*/
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list_add(&smi_msg->link, &intf->waiting_msgs);
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break;
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}
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}
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if (!run_to_completion)
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spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);
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/*
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* If the pretimout count is non-zero, decrement one from it and
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* deliver pretimeouts to all the users.
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*/
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if (atomic_add_unless(&intf->watchdog_pretimeouts_to_deliver, -1, 0)) {
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ipmi_user_t user;
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rcu_read_lock();
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list_for_each_entry_rcu(user, &intf->users, link) {
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if (user->handler->ipmi_watchdog_pretimeout)
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user->handler->ipmi_watchdog_pretimeout(
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user->handler_data);
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}
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rcu_read_unlock();
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}
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}
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static void smi_recv_tasklet(unsigned long val)
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{
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handle_new_recv_msgs((ipmi_smi_t) val);
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}
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/* Handle a new message from the lower layer. */
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void ipmi_smi_msg_received(ipmi_smi_t intf,
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struct ipmi_smi_msg *msg)
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{
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unsigned long flags = 0; /* keep us warning-free. */
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int rv;
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int run_to_completion;
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@ -3843,31 +3918,11 @@ void ipmi_smi_msg_received(ipmi_smi_t intf,
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run_to_completion = intf->run_to_completion;
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if (!run_to_completion)
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spin_lock_irqsave(&intf->waiting_msgs_lock, flags);
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if (!list_empty(&intf->waiting_msgs)) {
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list_add_tail(&msg->link, &intf->waiting_msgs);
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if (!run_to_completion)
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spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);
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goto out;
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}
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list_add_tail(&msg->link, &intf->waiting_msgs);
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if (!run_to_completion)
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spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);
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rv = handle_new_recv_msg(intf, msg);
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if (rv > 0) {
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/*
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* Could not handle the message now, just add it to a
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* list to handle later.
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*/
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run_to_completion = intf->run_to_completion;
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if (!run_to_completion)
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spin_lock_irqsave(&intf->waiting_msgs_lock, flags);
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list_add_tail(&msg->link, &intf->waiting_msgs);
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if (!run_to_completion)
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spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);
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} else if (rv == 0) {
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ipmi_free_smi_msg(msg);
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}
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tasklet_schedule(&intf->recv_tasklet);
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out:
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return;
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}
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@ -3875,16 +3930,8 @@ EXPORT_SYMBOL(ipmi_smi_msg_received);
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void ipmi_smi_watchdog_pretimeout(ipmi_smi_t intf)
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{
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ipmi_user_t user;
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rcu_read_lock();
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list_for_each_entry_rcu(user, &intf->users, link) {
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if (!user->handler->ipmi_watchdog_pretimeout)
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continue;
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user->handler->ipmi_watchdog_pretimeout(user->handler_data);
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}
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rcu_read_unlock();
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atomic_set(&intf->watchdog_pretimeouts_to_deliver, 1);
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tasklet_schedule(&intf->recv_tasklet);
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}
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EXPORT_SYMBOL(ipmi_smi_watchdog_pretimeout);
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@ -3998,28 +4045,12 @@ static void ipmi_timeout_handler(long timeout_period)
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ipmi_smi_t intf;
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struct list_head timeouts;
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struct ipmi_recv_msg *msg, *msg2;
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struct ipmi_smi_msg *smi_msg, *smi_msg2;
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unsigned long flags;
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int i;
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rcu_read_lock();
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list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
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/* See if any waiting messages need to be processed. */
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spin_lock_irqsave(&intf->waiting_msgs_lock, flags);
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list_for_each_entry_safe(smi_msg, smi_msg2,
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&intf->waiting_msgs, link) {
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if (!handle_new_recv_msg(intf, smi_msg)) {
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list_del(&smi_msg->link);
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ipmi_free_smi_msg(smi_msg);
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} else {
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/*
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* To preserve message order, quit if we
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* can't handle a message.
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*/
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break;
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}
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}
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spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);
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tasklet_schedule(&intf->recv_tasklet);
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/*
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* Go through the seq table and find any messages that
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@ -320,16 +320,8 @@ static int register_xaction_notifier(struct notifier_block *nb)
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static void deliver_recv_msg(struct smi_info *smi_info,
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struct ipmi_smi_msg *msg)
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{
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/* Deliver the message to the upper layer with the lock
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released. */
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if (smi_info->run_to_completion) {
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ipmi_smi_msg_received(smi_info->intf, msg);
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} else {
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spin_unlock(&(smi_info->si_lock));
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ipmi_smi_msg_received(smi_info->intf, msg);
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spin_lock(&(smi_info->si_lock));
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}
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/* Deliver the message to the upper layer. */
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ipmi_smi_msg_received(smi_info->intf, msg);
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}
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static void return_hosed_msg(struct smi_info *smi_info, int cCode)
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@ -481,9 +473,7 @@ static void handle_flags(struct smi_info *smi_info)
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start_clear_flags(smi_info);
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smi_info->msg_flags &= ~WDT_PRE_TIMEOUT_INT;
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spin_unlock(&(smi_info->si_lock));
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ipmi_smi_watchdog_pretimeout(smi_info->intf);
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spin_lock(&(smi_info->si_lock));
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} else if (smi_info->msg_flags & RECEIVE_MSG_AVAIL) {
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/* Messages available. */
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smi_info->curr_msg = ipmi_alloc_smi_msg();
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