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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 2012-03-28 14:42:49 -07:00 committed by Linus Torvalds
parent 828dc9da50
commit 7adf579c8b
2 changed files with 88 additions and 67 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

141
drivers/char/ipmi/ipmi_msghandler.c
View File

@ -46,6 +46,7 @@
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/rcupdate.h>
#include <linux/interrupt.h>
#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

14
drivers/char/ipmi/ipmi_si_intf.c
View File

@ -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();