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Commit 9ca15af3 authored by Corey Minyard's avatar Corey Minyard
Browse files

ipmi: Fix issues with BMC refcounts 



BMC device refcounts were not being decremented after fetching from
driver_find_device().  Also, document the use of ipmidriver_mutex
and tighten it's span some by incrementing the BMC's usecount in
the BMC find routines and not later.  This will be important for
future changes where a long mutex hold area will complicate things.

Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
parent eae4a36a

drivers/char/ipmi/ipmi_msghandler.c

+35 −16
Original line number Diff line number Diff line
@@ -526,6 +526,11 @@ static struct platform_driver ipmidriver = { 
		.bus = &platform_bus_type

	}

};

/*

 * This mutex protects adding/removing BMCs on the ipmidriver's device

 * list.  This way we can pull items out of the driver's list and reuse

 * them.

 */

static DEFINE_MUTEX(ipmidriver_mutex);



static LIST_HEAD(ipmi_interfaces);
@@ -2440,16 +2445,23 @@ static int __find_bmc_guid(struct device *dev, void *data) 
	return memcmp(to_bmc_device(dev)->guid, id, 16) == 0;

}



/*

 * Must be called with ipmidriver_mutex held.  Returns with the

 * bmc's usecount incremented, if it is non-NULL.

 */

static struct bmc_device *ipmi_find_bmc_guid(struct device_driver *drv,

					     unsigned char *guid)

{

	struct device *dev;

	struct bmc_device *bmc = NULL;



	dev = driver_find_device(drv, NULL, guid, __find_bmc_guid);

	if (dev)

		return to_bmc_device(dev);

	else

		return NULL;

	if (dev) {

		bmc = to_bmc_device(dev);

		kref_get(&bmc->usecount);

		put_device(dev);

	}

	return bmc;

}



struct prod_dev_id {
@@ -2470,6 +2482,10 @@ static int __find_bmc_prod_dev_id(struct device *dev, void *data) 
		&& bmc->id.device_id == id->device_id);

}



/*

 * Must be called with ipmidriver_mutex held.  Returns with the

 * bmc's usecount incremented, if it is non-NULL.

 */

static struct bmc_device *ipmi_find_bmc_prod_dev_id(

	struct device_driver *drv,

	unsigned int product_id, unsigned char device_id)
@@ -2479,12 +2495,15 @@ static struct bmc_device *ipmi_find_bmc_prod_dev_id( 
		.device_id = device_id,

	};

	struct device *dev;

	struct bmc_device *bmc = NULL;



	dev = driver_find_device(drv, NULL, &id, __find_bmc_prod_dev_id);

	if (dev)

		return to_bmc_device(dev);

	else

		return NULL;

	if (dev) {

		bmc = to_bmc_device(dev);

		kref_get(&bmc->usecount);

		put_device(dev);

	}

	return bmc;

}



static void
@@ -2514,8 +2533,8 @@ static void ipmi_bmc_unregister(ipmi_smi_t intf) 


	mutex_lock(&ipmidriver_mutex);

	kref_put(&bmc->usecount, cleanup_bmc_device);

	intf->bmc = NULL;

	mutex_unlock(&ipmidriver_mutex);

	intf->bmc = NULL;

}



static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum)
@@ -2524,18 +2543,18 @@ static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum) 
	struct bmc_device *bmc = intf->bmc;

	struct bmc_device *old_bmc;



	mutex_lock(&ipmidriver_mutex);



	/*

	 * Try to find if there is an bmc_device struct

	 * representing the interfaced BMC already

	 */

	mutex_lock(&ipmidriver_mutex);

	if (bmc->guid_set)

		old_bmc = ipmi_find_bmc_guid(&ipmidriver.driver, bmc->guid);

	else

		old_bmc = ipmi_find_bmc_prod_dev_id(&ipmidriver.driver,

						    bmc->id.product_id,

						    bmc->id.device_id);

	mutex_unlock(&ipmidriver_mutex);



	/*

	 * If there is already an bmc_device, free the new one,
@@ -2546,9 +2565,6 @@ static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum) 
		intf->bmc = old_bmc;

		bmc = old_bmc;



		kref_get(&bmc->usecount);

		mutex_unlock(&ipmidriver_mutex);



		printk(KERN_INFO

		       "ipmi: interfacing existing BMC (man_id: 0x%6.6x,"

		       " prod_id: 0x%4.4x, dev_id: 0x%2.2x)\n",
@@ -2558,14 +2574,17 @@ static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum) 
	} else {

		unsigned char orig_dev_id = bmc->id.device_id;

		int warn_printed = 0;

		struct bmc_device *tmp_bmc;



		snprintf(bmc->name, sizeof(bmc->name),

			 "ipmi_bmc.%4.4x", bmc->id.product_id);

		bmc->pdev.name = bmc->name;



		while (ipmi_find_bmc_prod_dev_id(&ipmidriver.driver,

		mutex_lock(&ipmidriver_mutex);

		while ((tmp_bmc = ipmi_find_bmc_prod_dev_id(&ipmidriver.driver,

						 bmc->id.product_id,

						 bmc->id.device_id)) {

						 bmc->id.device_id))) {

			kref_put(&tmp_bmc->usecount, cleanup_bmc_device);

			if (!warn_printed) {

				printk(KERN_WARNING PFX

				       "This machine has two different BMCs"