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ipmi: Don't initialize anything in the core until something uses it 

The IPMI driver was recently modified to use SRCU, but it turns out
this uses a chunk of percpu memory, even if IPMI is never used.

So modify thing to on initialize on the first use.  There was already
code to sort of handle this for handling init races, so piggy back
on top of that, and simplify it in the process.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reported-by: Tejun Heo <tj@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # 4.18
This commit is contained in:
Corey Minyard 2018-12-20 16:50:23 -06:00
parent 77f8269606
commit 913a89f009
1 changed files with 80 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

143
drivers/char/ipmi/ipmi_msghandler.c
View File

@ -63,7 +63,8 @@ static void ipmi_debug_msg(const char *title, unsigned char *data,
{ }
#endif
static int initialized;
static bool initialized;
static bool drvregistered;
enum ipmi_panic_event_op {
IPMI_SEND_PANIC_EVENT_NONE,
@ -613,7 +614,7 @@ static DEFINE_MUTEX(ipmidriver_mutex);
static LIST_HEAD(ipmi_interfaces);
static DEFINE_MUTEX(ipmi_interfaces_mutex);
DEFINE_STATIC_SRCU(ipmi_interfaces_srcu);
struct srcu_struct ipmi_interfaces_srcu;
/*
* List of watchers that want to know when smi's are added and deleted.
@ -721,7 +722,15 @@ struct watcher_entry {
int ipmi_smi_watcher_register(struct ipmi_smi_watcher *watcher)
{
struct ipmi_smi *intf;
int index;
int index, rv;
/*
* Make sure the driver is actually initialized, this handles
* problems with initialization order.
*/
rv = ipmi_init_msghandler();
if (rv)
return rv;
mutex_lock(&smi_watchers_mutex);
@ -1077,7 +1086,7 @@ int ipmi_create_user(unsigned int if_num,
{
unsigned long flags;
struct ipmi_user *new_user;
int rv = 0, index;
int rv, index;
struct ipmi_smi *intf;
/*
@ -1095,18 +1104,9 @@ int ipmi_create_user(unsigned int if_num,
* Make sure the driver is actually initialized, this handles
* problems with initialization order.
*/
if (!initialized) {
rv = ipmi_init_msghandler();
if (rv)
return rv;
/*
* The init code doesn't return an error if it was turned
* off, but it won't initialize. Check that.
*/
if (!initialized)
return -ENODEV;
}
rv = ipmi_init_msghandler();
if (rv)
return rv;
new_user = kmalloc(sizeof(*new_user), GFP_KERNEL);
if (!new_user)
@ -3301,17 +3301,9 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers,
* Make sure the driver is actually initialized, this handles
* problems with initialization order.
*/
if (!initialized) {
rv = ipmi_init_msghandler();
if (rv)
return rv;
/*
* The init code doesn't return an error if it was turned
* off, but it won't initialize. Check that.
*/
if (!initialized)
return -ENODEV;
}
rv = ipmi_init_msghandler();
if (rv)
return rv;
intf = kzalloc(sizeof(*intf), GFP_KERNEL);
if (!intf)
@ -5027,6 +5019,22 @@ static int panic_event(struct notifier_block *this,
return NOTIFY_DONE;
}
/* Must be called with ipmi_interfaces_mutex held. */
static int ipmi_register_driver(void)
{
int rv;
if (drvregistered)
return 0;
rv = driver_register(&ipmidriver.driver);
if (rv)
pr_err("Could not register IPMI driver\n");
else
drvregistered = true;
return rv;
}
static struct notifier_block panic_block = {
.notifier_call = panic_event,
.next = NULL,
@ -5037,66 +5045,75 @@ static int ipmi_init_msghandler(void)
{
int rv;
mutex_lock(&ipmi_interfaces_mutex);
rv = ipmi_register_driver();
if (rv)
goto out;
if (initialized)
return 0;
goto out;
rv = driver_register(&ipmidriver.driver);
if (rv) {
pr_err("Could not register IPMI driver\n");
return rv;
}
pr_info("version " IPMI_DRIVER_VERSION "\n");
init_srcu_struct(&ipmi_interfaces_srcu);
timer_setup(&ipmi_timer, ipmi_timeout, 0);
mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
initialized = 1;
initialized = true;
return 0;
out:
mutex_unlock(&ipmi_interfaces_mutex);
return rv;
}
static int __init ipmi_init_msghandler_mod(void)
{
ipmi_init_msghandler();
return 0;
int rv;
pr_info("version " IPMI_DRIVER_VERSION "\n");
mutex_lock(&ipmi_interfaces_mutex);
rv = ipmi_register_driver();
mutex_unlock(&ipmi_interfaces_mutex);
return rv;
}
static void __exit cleanup_ipmi(void)
{
int count;
if (!initialized)
return;
if (initialized) {
atomic_notifier_chain_unregister(&panic_notifier_list,
&panic_block);
atomic_notifier_chain_unregister(&panic_notifier_list, &panic_block);
/*
* This can't be called if any interfaces exist, so no worry
* about shutting down the interfaces.
*/
/*
* This can't be called if any interfaces exist, so no worry
* about shutting down the interfaces.
*/
/*
* Tell the timer to stop, then wait for it to stop. This
* avoids problems with race conditions removing the timer
* here.
*/
atomic_inc(&stop_operation);
del_timer_sync(&ipmi_timer);
/*
* Tell the timer to stop, then wait for it to stop. This
* avoids problems with race conditions removing the timer
* here.
*/
atomic_inc(&stop_operation);
del_timer_sync(&ipmi_timer);
initialized = false;
driver_unregister(&ipmidriver.driver);
/* Check for buffer leaks. */
count = atomic_read(&smi_msg_inuse_count);
if (count != 0)
pr_warn("SMI message count %d at exit\n", count);
count = atomic_read(&recv_msg_inuse_count);
if (count != 0)
pr_warn("recv message count %d at exit\n", count);
initialized = 0;
/* Check for buffer leaks. */
count = atomic_read(&smi_msg_inuse_count);
if (count != 0)
pr_warn("SMI message count %d at exit\n", count);
count = atomic_read(&recv_msg_inuse_count);
if (count != 0)
pr_warn("recv message count %d at exit\n", count);
cleanup_srcu_struct(&ipmi_interfaces_srcu);
}
if (drvregistered)
driver_unregister(&ipmidriver.driver);
}
module_exit(cleanup_ipmi);