[PATCH] IPMI: Allow hot system interface remove

This modifies the IPMI driver so that a lower-level interface can be
dynamically removed while in use so it can support hot-removal of hardware.

It also adds the ability to specify and dynamically change the IPMI interface
the watchdog timer and the poweroff code use.

Signed-off-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 78 insertions, 43 deletions

diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 73f759eaa5a6..90fb2a541916 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -135,6 +135,7 @@
 static int nowayout = WATCHDOG_NOWAYOUT;
 
 static ipmi_user_t watchdog_user = NULL;
+static int watchdog_ifnum;
 
 /* Default the timeout to 10 seconds. */
 static int timeout = 10;
@@ -161,6 +162,8 @@ static struct fasync_struct *fasync_q = NULL;
 static char pretimeout_since_last_heartbeat = 0;
 static char expect_close;
 
+static int ifnum_to_use = -1;
+
 static DECLARE_RWSEM(register_sem);
 
 /* Parameters to ipmi_set_timeout */
@@ -169,6 +172,8 @@ static DECLARE_RWSEM(register_sem);
 #define IPMI_SET_TIMEOUT_FORCE_HB		2
 
 static int ipmi_set_timeout(int do_heartbeat);
+static void ipmi_register_watchdog(int ipmi_intf);
+static void ipmi_unregister_watchdog(int ipmi_intf);
 
 /* If true, the driver will start running as soon as it is configured
    and ready. */
@@ -245,6 +250,26 @@ static int get_param_str(char *buffer, struct kernel_param *kp)
 	return strlen(buffer);
 }
 
+
+static int set_param_wdog_ifnum(const char *val, struct kernel_param *kp)
+{
+	int rv = param_set_int(val, kp);
+	if (rv)
+		return rv;
+	if ((ifnum_to_use < 0) || (ifnum_to_use == watchdog_ifnum))
+		return 0;
+
+	ipmi_unregister_watchdog(watchdog_ifnum);
+	ipmi_register_watchdog(ifnum_to_use);
+	return 0;
+}
+
+module_param_call(ifnum_to_use, set_param_wdog_ifnum, get_param_int,
+		  &ifnum_to_use, 0644);
+MODULE_PARM_DESC(ifnum_to_use, "The interface number to use for the watchdog "
+		 "timer.  Setting to -1 defaults to the first registered "
+		 "interface");
+
 module_param_call(timeout, set_param_int, get_param_int, &timeout, 0644);
 MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
 
@@ -263,12 +288,13 @@ module_param_call(preop, set_param_str, get_param_str, preop_op, 0644);
 MODULE_PARM_DESC(preop, "Pretimeout driver operation.  One of: "
 		 "preop_none, preop_panic, preop_give_data.");
 
-module_param(start_now, int, 0);
+module_param(start_now, int, 0444);
 MODULE_PARM_DESC(start_now, "Set to 1 to start the watchdog as"
 		 "soon as the driver is loaded.");
 
 module_param(nowayout, int, 0644);
-MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+		 "(default=CONFIG_WATCHDOG_NOWAYOUT)");
 
 /* Default state of the timer. */
 static unsigned char ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
@@ -872,6 +898,11 @@ static void ipmi_register_watchdog(int ipmi_intf)
 	if (watchdog_user)
 		goto out;
 
+	if ((ifnum_to_use >= 0) && (ifnum_to_use != ipmi_intf))
+		goto out;
+
+	watchdog_ifnum = ipmi_intf;
+
 	rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
 	if (rv < 0) {
 		printk(KERN_CRIT PFX "Unable to register with ipmi\n");
@@ -901,6 +932,39 @@ static void ipmi_register_watchdog(int ipmi_intf)
 	}
 }
 
+static void ipmi_unregister_watchdog(int ipmi_intf)
+{
+	int rv;
+
+	down_write(&register_sem);
+
+	if (!watchdog_user)
+		goto out;
+
+	if (watchdog_ifnum != ipmi_intf)
+		goto out;
+
+	/* Make sure no one can call us any more. */
+	misc_deregister(&ipmi_wdog_miscdev);
+
+	/* Wait to make sure the message makes it out.  The lower layer has
+	   pointers to our buffers, we want to make sure they are done before
+	   we release our memory. */
+	while (atomic_read(&set_timeout_tofree))
+		schedule_timeout_uninterruptible(1);
+
+	/* Disconnect from IPMI. */
+	rv = ipmi_destroy_user(watchdog_user);
+	if (rv) {
+		printk(KERN_WARNING PFX "error unlinking from IPMI: %d\n",
+		       rv);
+	}
+	watchdog_user = NULL;
+
+ out:
+	up_write(&register_sem);
+}
+
 #ifdef HAVE_NMI_HANDLER
 static int
 ipmi_nmi(void *dev_id, int cpu, int handled)
@@ -1004,9 +1068,7 @@ static void ipmi_new_smi(int if_num, struct device *device)
 
 static void ipmi_smi_gone(int if_num)
 {
-	/* This can never be called, because once the watchdog is
-	   registered, the interface can't go away until the watchdog
-	   is unregistered. */
+	ipmi_unregister_watchdog(if_num);
 }
 
 static struct ipmi_smi_watcher smi_watcher =
@@ -1148,30 +1210,32 @@ static int __init ipmi_wdog_init(void)
 
 	check_parms();
 
+	register_reboot_notifier(&wdog_reboot_notifier);
+	atomic_notifier_chain_register(&panic_notifier_list,
+			&wdog_panic_notifier);
+
 	rv = ipmi_smi_watcher_register(&smi_watcher);
 	if (rv) {
 #ifdef HAVE_NMI_HANDLER
 		if (preaction_val == WDOG_PRETIMEOUT_NMI)
 			release_nmi(&ipmi_nmi_handler);
 #endif
+		atomic_notifier_chain_unregister(&panic_notifier_list,
+						 &wdog_panic_notifier);
+		unregister_reboot_notifier(&wdog_reboot_notifier);
 		printk(KERN_WARNING PFX "can't register smi watcher\n");
 		return rv;
 	}
 
-	register_reboot_notifier(&wdog_reboot_notifier);
-	atomic_notifier_chain_register(&panic_notifier_list,
-			&wdog_panic_notifier);
-
 	printk(KERN_INFO PFX "driver initialized\n");
 
 	return 0;
 }
 
-static __exit void ipmi_unregister_watchdog(void)
+static void __exit ipmi_wdog_exit(void)
 {
-	int rv;
-
-	down_write(&register_sem);
+	ipmi_smi_watcher_unregister(&smi_watcher);
+	ipmi_unregister_watchdog(watchdog_ifnum);
 
 #ifdef HAVE_NMI_HANDLER
 	if (nmi_handler_registered)
@@ -1179,37 +1243,8 @@ static __exit void ipmi_unregister_watchdog(void)
 #endif
 
 	atomic_notifier_chain_unregister(&panic_notifier_list,
-			&wdog_panic_notifier);
+					 &wdog_panic_notifier);
 	unregister_reboot_notifier(&wdog_reboot_notifier);
-
-	if (! watchdog_user)
-		goto out;
-
-	/* Make sure no one can call us any more. */
-	misc_deregister(&ipmi_wdog_miscdev);
-
-	/* Wait to make sure the message makes it out.  The lower layer has
-	   pointers to our buffers, we want to make sure they are done before
-	   we release our memory. */
-	while (atomic_read(&set_timeout_tofree))
-		schedule_timeout_uninterruptible(1);
-
-	/* Disconnect from IPMI. */
-	rv = ipmi_destroy_user(watchdog_user);
-	if (rv) {
-		printk(KERN_WARNING PFX "error unlinking from IPMI: %d\n",
-		       rv);
-	}
-	watchdog_user = NULL;
-
- out:
-	up_write(&register_sem);
-}
-
-static void __exit ipmi_wdog_exit(void)
-{
-	ipmi_smi_watcher_unregister(&smi_watcher);
-	ipmi_unregister_watchdog();
 }
 module_exit(ipmi_wdog_exit);
 module_init(ipmi_wdog_init);