From 7adf579c8babf62026e6aab1dee85e6b104d9936 Mon Sep 17 00:00:00 2001 From: Corey Minyard Date: Wed, 28 Mar 2012 14:42:49 -0700 Subject: [PATCH] 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/ipmi/ipmi_msghandler.c | 141 +++++++++++++++++----------- drivers/char/ipmi/ipmi_si_intf.c | 14 +-- 2 files changed, 88 insertions(+), 67 deletions(-) diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index 58c0e6387cf7..289ab506b79b 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -46,6 +46,7 @@ #include #include #include +#include #define PFX "IPMI message handler: " @@ -53,6 +54,8 @@ static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void); static int ipmi_init_msghandler(void); +static void smi_recv_tasklet(unsigned long); +static void handle_new_recv_msgs(ipmi_smi_t intf); static int initialized; @@ -355,12 +358,15 @@ struct ipmi_smi { int curr_seq; /* - * Messages that were delayed for some reason (out of memory, - * for instance), will go in here to be processed later in a - * periodic timer interrupt. + * Messages queued for delivery. If delivery fails (out of memory + * for instance), They will stay in here to be processed later in a + * periodic timer interrupt. The tasklet is for handling received + * messages directly from the handler. */ spinlock_t waiting_msgs_lock; struct list_head waiting_msgs; + atomic_t watchdog_pretimeouts_to_deliver; + struct tasklet_struct recv_tasklet; /* * The list of command receivers that are registered for commands @@ -493,6 +499,8 @@ static void clean_up_interface_data(ipmi_smi_t intf) struct cmd_rcvr *rcvr, *rcvr2; struct list_head list; + tasklet_kill(&intf->recv_tasklet); + free_smi_msg_list(&intf->waiting_msgs); free_recv_msg_list(&intf->waiting_events); @@ -2792,6 +2800,9 @@ void ipmi_poll_interface(ipmi_user_t user) if (intf->handlers->poll) intf->handlers->poll(intf->send_info); + + /* In case something came in */ + handle_new_recv_msgs(intf); } EXPORT_SYMBOL(ipmi_poll_interface); @@ -2860,6 +2871,10 @@ int ipmi_register_smi(struct ipmi_smi_handlers *handlers, #endif spin_lock_init(&intf->waiting_msgs_lock); INIT_LIST_HEAD(&intf->waiting_msgs); + tasklet_init(&intf->recv_tasklet, + smi_recv_tasklet, + (unsigned long) intf); + atomic_set(&intf->watchdog_pretimeouts_to_deliver, 0); spin_lock_init(&intf->events_lock); INIT_LIST_HEAD(&intf->waiting_events); intf->waiting_events_count = 0; @@ -3622,11 +3637,11 @@ static int handle_bmc_rsp(ipmi_smi_t intf, } /* - * Handle a new message. Return 1 if the message should be requeued, + * Handle a received message. Return 1 if the message should be requeued, * 0 if the message should be freed, or -1 if the message should not * be freed or requeued. */ -static int handle_new_recv_msg(ipmi_smi_t intf, +static int handle_one_recv_msg(ipmi_smi_t intf, struct ipmi_smi_msg *msg) { int requeue; @@ -3784,12 +3799,72 @@ static int handle_new_recv_msg(ipmi_smi_t intf, return requeue; } +/* + * If there are messages in the queue or pretimeouts, handle them. + */ +static void handle_new_recv_msgs(ipmi_smi_t intf) +{ + struct ipmi_smi_msg *smi_msg; + unsigned long flags = 0; + int rv; + int run_to_completion = intf->run_to_completion; + + /* See if any waiting messages need to be processed. */ + if (!run_to_completion) + spin_lock_irqsave(&intf->waiting_msgs_lock, flags); + while (!list_empty(&intf->waiting_msgs)) { + smi_msg = list_entry(intf->waiting_msgs.next, + struct ipmi_smi_msg, link); + list_del(&smi_msg->link); + if (!run_to_completion) + spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags); + rv = handle_one_recv_msg(intf, smi_msg); + if (!run_to_completion) + spin_lock_irqsave(&intf->waiting_msgs_lock, flags); + if (rv == 0) { + /* Message handled */ + ipmi_free_smi_msg(smi_msg); + } else if (rv < 0) { + /* Fatal error on the message, del but don't free. */ + } else { + /* + * To preserve message order, quit if we + * can't handle a message. + */ + list_add(&smi_msg->link, &intf->waiting_msgs); + break; + } + } + if (!run_to_completion) + spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags); + + /* + * If the pretimout count is non-zero, decrement one from it and + * deliver pretimeouts to all the users. + */ + if (atomic_add_unless(&intf->watchdog_pretimeouts_to_deliver, -1, 0)) { + ipmi_user_t user; + + rcu_read_lock(); + list_for_each_entry_rcu(user, &intf->users, link) { + if (user->handler->ipmi_watchdog_pretimeout) + user->handler->ipmi_watchdog_pretimeout( + user->handler_data); + } + rcu_read_unlock(); + } +} + +static void smi_recv_tasklet(unsigned long val) +{ + handle_new_recv_msgs((ipmi_smi_t) val); +} + /* Handle a new message from the lower layer. */ void ipmi_smi_msg_received(ipmi_smi_t intf, struct ipmi_smi_msg *msg) { unsigned long flags = 0; /* keep us warning-free. */ - int rv; int run_to_completion; @@ -3843,31 +3918,11 @@ void ipmi_smi_msg_received(ipmi_smi_t intf, run_to_completion = intf->run_to_completion; if (!run_to_completion) spin_lock_irqsave(&intf->waiting_msgs_lock, flags); - if (!list_empty(&intf->waiting_msgs)) { - list_add_tail(&msg->link, &intf->waiting_msgs); - if (!run_to_completion) - spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags); - goto out; - } + list_add_tail(&msg->link, &intf->waiting_msgs); if (!run_to_completion) spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags); - rv = handle_new_recv_msg(intf, msg); - if (rv > 0) { - /* - * Could not handle the message now, just add it to a - * list to handle later. - */ - run_to_completion = intf->run_to_completion; - if (!run_to_completion) - spin_lock_irqsave(&intf->waiting_msgs_lock, flags); - list_add_tail(&msg->link, &intf->waiting_msgs); - if (!run_to_completion) - spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags); - } else if (rv == 0) { - ipmi_free_smi_msg(msg); - } - + tasklet_schedule(&intf->recv_tasklet); out: return; } @@ -3875,16 +3930,8 @@ EXPORT_SYMBOL(ipmi_smi_msg_received); void ipmi_smi_watchdog_pretimeout(ipmi_smi_t intf) { - ipmi_user_t user; - - rcu_read_lock(); - list_for_each_entry_rcu(user, &intf->users, link) { - if (!user->handler->ipmi_watchdog_pretimeout) - continue; - - user->handler->ipmi_watchdog_pretimeout(user->handler_data); - } - rcu_read_unlock(); + atomic_set(&intf->watchdog_pretimeouts_to_deliver, 1); + tasklet_schedule(&intf->recv_tasklet); } EXPORT_SYMBOL(ipmi_smi_watchdog_pretimeout); @@ -3998,28 +4045,12 @@ static void ipmi_timeout_handler(long timeout_period) ipmi_smi_t intf; struct list_head timeouts; struct ipmi_recv_msg *msg, *msg2; - struct ipmi_smi_msg *smi_msg, *smi_msg2; unsigned long flags; int i; rcu_read_lock(); list_for_each_entry_rcu(intf, &ipmi_interfaces, link) { - /* See if any waiting messages need to be processed. */ - spin_lock_irqsave(&intf->waiting_msgs_lock, flags); - list_for_each_entry_safe(smi_msg, smi_msg2, - &intf->waiting_msgs, link) { - if (!handle_new_recv_msg(intf, smi_msg)) { - list_del(&smi_msg->link); - ipmi_free_smi_msg(smi_msg); - } else { - /* - * To preserve message order, quit if we - * can't handle a message. - */ - break; - } - } - spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags); + tasklet_schedule(&intf->recv_tasklet); /* * Go through the seq table and find any messages that diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c index 73ebbb1a3269..01e53cd105dd 100644 --- a/drivers/char/ipmi/ipmi_si_intf.c +++ b/drivers/char/ipmi/ipmi_si_intf.c @@ -320,16 +320,8 @@ static int register_xaction_notifier(struct notifier_block *nb) static void deliver_recv_msg(struct smi_info *smi_info, struct ipmi_smi_msg *msg) { - /* Deliver the message to the upper layer with the lock - released. */ - - if (smi_info->run_to_completion) { - ipmi_smi_msg_received(smi_info->intf, msg); - } else { - spin_unlock(&(smi_info->si_lock)); - ipmi_smi_msg_received(smi_info->intf, msg); - spin_lock(&(smi_info->si_lock)); - } + /* Deliver the message to the upper layer. */ + ipmi_smi_msg_received(smi_info->intf, msg); } static void return_hosed_msg(struct smi_info *smi_info, int cCode) @@ -481,9 +473,7 @@ static void handle_flags(struct smi_info *smi_info) start_clear_flags(smi_info); smi_info->msg_flags &= ~WDT_PRE_TIMEOUT_INT; - spin_unlock(&(smi_info->si_lock)); ipmi_smi_watchdog_pretimeout(smi_info->intf); - spin_lock(&(smi_info->si_lock)); } else if (smi_info->msg_flags & RECEIVE_MSG_AVAIL) { /* Messages available. */ smi_info->curr_msg = ipmi_alloc_smi_msg(); -- 2.20.1