[PATCH v5 21/48] ipmi: Register with kernel power-off handler

Guenter Roeck
2014-11-06T16:59:18Z

directly. Register with high priority to reflect that the original code
overwrites pm_power_off unconditionally.

Register power-off handler after the ipmi system is ready, and unregister
it prior to cleanup. This avoids having to check for the ready variable
in the poweroff callback.

Reviewed-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v5:
- Rebase to v3.18-rc3
v4:
- Do not use notifiers but internal functions and data structures to manage
the list of power-off handlers. Drop unused parameters from callbacks, and
make the power-off function type void
v3:
- Replace poweroff in all newly introduced variables and in text
with power_off or power-off as appropriate
- Replace POWEROFF_PRIORITY_xxx with POWER_OFF_PRIORITY_xxx
v2:
- Use define to specify poweroff handler priority
- Use pr_warn instead of pr_err
- Call unregister_power_off_handler on exit only if not already unregistered

drivers/char/ipmi/ipmi_poweroff.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_poweroff.c b/drivers/char/ipmi/ipmi_poweroff.c
index 9f2e3be..4ae2f22 100644
--- a/drivers/char/ipmi/ipmi_poweroff.c
+++ b/drivers/char/ipmi/ipmi_poweroff.c
@@ -63,9 +63,6 @@ static ipmi_user_t ipmi_user;
static int ipmi_ifnum;
static void (*specific_poweroff_func)(ipmi_user_t user);

-/* Holds the old poweroff function so we can restore it on removal. */
-static void (*old_poweroff_func)(void);
-
static int set_param_ifnum(const char *val, struct kernel_param *kp)
{
int rv = param_set_int(val, kp);
@@ -544,15 +541,17 @@ static struct poweroff_function poweroff_functions[] = {

/* Called on a powerdown request. */
-static void ipmi_poweroff_function(void)
+static void ipmi_poweroff_function(struct power_off_handler_block *this)
{
- if (!ready)
- return;
-
/* Use run-to-completion mode, since interrupts may be off. */
specific_poweroff_func(ipmi_user);
}

+static struct power_off_handler_block ipmi_power_off_hb = {
+ .handler = ipmi_poweroff_function,
+ .priority = POWER_OFF_PRIORITY_HIGH,
+};
+
/* Wait for an IPMI interface to be installed, the first one installed
will be grabbed by this code and used to perform the powerdown. */
static void ipmi_po_new_smi(int if_num, struct device *device)
@@ -631,9 +630,12 @@ static void ipmi_po_new_smi(int if_num, struct device *device)
printk(KERN_INFO PFX "Found a %s style poweroff function\n",
poweroff_functions[i].platform_type);
specific_poweroff_func = poweroff_functions[i].poweroff_func;
- old_poweroff_func = pm_power_off;
- pm_power_off = ipmi_poweroff_function;
+
ready = 1;
+
+ rv = register_power_off_handler(&ipmi_power_off_hb);
+ if (rv)
+ pr_warn(PFX "failed to register power-off handler\n");
}

static void ipmi_po_smi_gone(int if_num)
@@ -644,9 +646,10 @@ static void ipmi_po_smi_gone(int if_num)
if (ipmi_ifnum != if_num)
return;

+ unregister_power_off_handler(&ipmi_power_off_hb);
+
ready = 0;
ipmi_destroy_user(ipmi_user);
- pm_power_off = old_poweroff_func;
}

static struct ipmi_smi_watcher smi_watcher = {
@@ -733,11 +736,11 @@ static void __exit ipmi_poweroff_cleanup(void)
ipmi_smi_watcher_unregister(&smi_watcher);

if (ready) {
+ unregister_power_off_handler(&ipmi_power_off_hb);
rv = ipmi_destroy_user(ipmi_user);
if (rv)
printk(KERN_ERR PFX "could not cleanup the IPMI"
" user: 0x%x\n", rv);
- pm_power_off = old_poweroff_func;
}
}
module_exit(ipmi_poweroff_cleanup);
--
1.9.1