From b2cfd8ab4add53c2070367bfee2f5b738f51698d Mon Sep 17 00:00:00 2001
From: Corey Minyard <cminyard@mvista.com>
Date: Fri, 1 Sep 2017 16:32:40 -0500
Subject: [PATCH] ipmi: Rework device id and guid handling to catch changing BMCs
Git-commit: b2cfd8ab4add53c2070367bfee2f5b738f51698d
Patch-mainline: v4.15-rc1
References: FATE#326156
A BMC's guid or device id info may change dynamically, this could
result in a different configuration that needs to be done. Adjust
the BMCs dynamically.
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/char/ipmi/ipmi_msghandler.c | 240 +++++++++++++++++++---------
1 file changed, 167 insertions(+), 73 deletions(-)
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 9d4a9a94fdc6..1da0b3cca6aa 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -265,18 +265,24 @@ struct ipmi_proc_entry {
};
#endif
+/*
+ * Note that the product id, manufacturer id, guid, and device id are
+ * immutable in this structure, so dyn_mutex is not required for
+ * accessing those. If those change on a BMC, a new BMC is allocated.
+ */
struct bmc_device {
struct platform_device pdev;
- struct list_head intfs;
+ struct list_head intfs; /* Interfaces on this BMC. */
struct ipmi_device_id id;
struct ipmi_device_id fetch_id;
int dyn_id_set;
unsigned long dyn_id_expiry;
- struct mutex dyn_mutex; /* protects id & dyn* fields */
+ struct mutex dyn_mutex; /* Protects id, intfs, & dyn* */
u8 guid[16];
u8 fetch_guid[16];
int dyn_guid_set;
struct kref usecount;
+ struct work_struct remove_work;
};
#define to_bmc_device(x) container_of((x), struct bmc_device, pdev.dev)
@@ -423,6 +429,7 @@ struct ipmi_smi {
bool bmc_registered;
struct list_head bmc_link;
char *my_dev_name;
+ bool in_bmc_register; /* Handle recursive situations. Yuck. */
/*
* This is the lower-layer's sender routine. Note that you
@@ -509,10 +516,7 @@ struct ipmi_smi {
* it. Note that the message will still be freed by the
* caller. This only works on the system interface.
*
- * The only user outside of initialization an panic handling is
- * the dynamic device id fetching, so no mutex is currently
- * required on this. If more users come along, some sort of
- * mutex will be required.
+ * Protected by bmc_reg_mutex.
*/
void (*null_user_handler)(ipmi_smi_t intf, struct ipmi_recv_msg *msg);
@@ -541,6 +545,11 @@ struct ipmi_smi {
#define to_si_intf_from_dev(device) container_of(device, struct ipmi_smi, dev)
static void __get_guid(ipmi_smi_t intf);
+static void __ipmi_bmc_unregister(ipmi_smi_t intf);
+static int __ipmi_bmc_register(ipmi_smi_t intf,
+ struct ipmi_device_id *id,
+ bool guid_set, u8 *guid, int intf_num);
+
/**
* The driver model view of the IPMI messaging driver.
@@ -552,9 +561,7 @@ static struct platform_driver ipmidriver = {
}
};
/*
- * 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.
+ * This mutex keeps us from adding the same BMC twice.
*/
static DEFINE_MUTEX(ipmidriver_mutex);
@@ -2197,12 +2204,13 @@ static int __get_device_id(ipmi_smi_t intf, struct bmc_device *bmc)
* Except for the first time this is called (in ipmi_register_smi()),
* this will always return good data;
*/
-static int bmc_get_device_id(ipmi_smi_t intf, struct bmc_device *bmc,
- struct ipmi_device_id *id,
- bool *guid_set, u8 *guid)
+static int __bmc_get_device_id(ipmi_smi_t intf, struct bmc_device *bmc,
+ struct ipmi_device_id *id,
+ bool *guid_set, u8 *guid, int intf_num)
{
int rv = 0;
int prev_dyn_id_set, prev_guid_set;
+ bool intf_set = intf != NULL;
if (!intf) {
mutex_lock(&bmc->dyn_mutex);
@@ -2231,27 +2239,60 @@ static int bmc_get_device_id(ipmi_smi_t intf, struct bmc_device *bmc,
}
/* If we have a valid and current ID, just return that. */
- if (bmc->dyn_id_set && time_is_after_jiffies(bmc->dyn_id_expiry))
- goto out;
+ if (intf->in_bmc_register ||
+ (bmc->dyn_id_set && time_is_after_jiffies(bmc->dyn_id_expiry)))
+ goto out_noprocessing;
prev_guid_set = bmc->dyn_guid_set;
__get_guid(intf);
- if (bmc->dyn_guid_set)
- memcpy(bmc->guid, bmc->fetch_guid, 16);
- else if (prev_guid_set)
- /*
- * The guid used to be valid and it failed to fetch,
- * just use the cached value.
- */
- bmc->dyn_guid_set = prev_guid_set;
-
prev_dyn_id_set = bmc->dyn_id_set;
rv = __get_device_id(intf, bmc);
if (rv)
goto out;
- memcpy(&bmc->id, &bmc->fetch_id, sizeof(bmc->id));
+ /*
+ * The guid, device id, manufacturer id, and product id should
+ * not change on a BMC. If it does we have to do some dancing.
+ */
+ if (!intf->bmc_registered
+ || (!prev_guid_set && bmc->dyn_guid_set)
+ || (!prev_dyn_id_set && bmc->dyn_id_set)
+ || (prev_guid_set && bmc->dyn_guid_set
+ && memcmp(bmc->guid, bmc->fetch_guid, 16))
+ || bmc->id.device_id != bmc->fetch_id.device_id
+ || bmc->id.manufacturer_id != bmc->fetch_id.manufacturer_id
+ || bmc->id.product_id != bmc->fetch_id.product_id) {
+ struct ipmi_device_id id = bmc->fetch_id;
+ int guid_set = bmc->dyn_guid_set;
+ u8 guid[16];
+
+ memcpy(guid, bmc->fetch_guid, 16);
+ mutex_unlock(&bmc->dyn_mutex);
+
+ __ipmi_bmc_unregister(intf);
+ /* Fill in the temporary BMC for good measure. */
+ intf->bmc->id = id;
+ intf->bmc->dyn_guid_set = guid_set;
+ memcpy(intf->bmc->guid, guid, 16);
+ rv = __ipmi_bmc_register(intf, &id, guid_set, guid, intf_num);
+
+ if (!intf_set) {
+ /*
+ * We weren't given the interface on the
+ * command line, so restart the operation on
+ * the next interface for the BMC.
+ */
+ mutex_unlock(&intf->bmc_reg_mutex);
+ mutex_lock(&bmc->dyn_mutex);
+ goto retry_bmc_lock;
+ }
+
+ /* We have a new BMC, set it up. */
+ bmc = intf->bmc;
+ mutex_lock(&bmc->dyn_mutex);
+ goto out_noprocessing;
+ }
bmc->dyn_id_expiry = jiffies + IPMI_DYN_DEV_ID_EXPIRY;
@@ -2260,15 +2301,28 @@ static int bmc_get_device_id(ipmi_smi_t intf, struct bmc_device *bmc,
rv = 0; /* Ignore failures if we have previous data. */
bmc->dyn_id_set = prev_dyn_id_set;
}
+ if (!rv) {
+ bmc->id = bmc->fetch_id;
+ if (bmc->dyn_guid_set)
+ memcpy(bmc->guid, bmc->fetch_guid, 16);
+ else if (prev_guid_set)
+ /*
+ * The guid used to be valid and it failed to fetch,
+ * just use the cached value.
+ */
+ bmc->dyn_guid_set = prev_guid_set;
+ }
+out_noprocessing:
+ if (!rv) {
+ if (id)
+ *id = bmc->id;
- if (id)
- *id = bmc->id;
-
- if (guid_set)
- *guid_set = bmc->dyn_guid_set;
+ if (guid_set)
+ *guid_set = bmc->dyn_guid_set;
- if (guid && bmc->dyn_guid_set)
- memcpy(guid, bmc->guid, 16);
+ if (guid && bmc->dyn_guid_set)
+ memcpy(guid, bmc->guid, 16);
+ }
mutex_unlock(&bmc->dyn_mutex);
mutex_unlock(&intf->bmc_reg_mutex);
@@ -2277,6 +2331,13 @@ static int bmc_get_device_id(ipmi_smi_t intf, struct bmc_device *bmc,
return rv;
}
+static int bmc_get_device_id(ipmi_smi_t intf, struct bmc_device *bmc,
+ struct ipmi_device_id *id,
+ bool *guid_set, u8 *guid)
+{
+ return __bmc_get_device_id(intf, bmc, id, guid_set, guid, -1);
+}
+
#ifdef CONFIG_PROC_FS
static int smi_ipmb_proc_show(struct seq_file *m, void *v)
{
@@ -2721,26 +2782,22 @@ static const struct device_type bmc_device_type = {
static int __find_bmc_guid(struct device *dev, void *data)
{
- unsigned char *id = data;
+ unsigned char *guid = data;
struct bmc_device *bmc;
- bool guid_set;
- u8 guid[16];
int rv;
if (dev->type != &bmc_device_type)
return 0;
bmc = to_bmc_device(dev);
- rv = bmc_get_device_id(NULL, bmc, NULL, &guid_set, guid);
- if (rv || !guid_set)
- return 0;
-
- return memcmp(guid, id, 16) == 0;
+ rv = bmc->dyn_guid_set && memcmp(bmc->guid, guid, 16) == 0;
+ if (rv)
+ rv = kref_get_unless_zero(&bmc->usecount);
+ return rv;
}
/*
- * Must be called with ipmidriver_mutex held. Returns with the
- * bmc's usecount incremented, if it is non-NULL.
+ * 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)
@@ -2751,7 +2808,6 @@ static struct bmc_device *ipmi_find_bmc_guid(struct device_driver *drv,
dev = driver_find_device(drv, NULL, guid, __find_bmc_guid);
if (dev) {
bmc = to_bmc_device(dev);
- kref_get(&bmc->usecount);
put_device(dev);
}
return bmc;
@@ -2766,24 +2822,21 @@ static int __find_bmc_prod_dev_id(struct device *dev, void *data)
{
struct prod_dev_id *cid = data;
struct bmc_device *bmc;
- struct ipmi_device_id id;
int rv;
if (dev->type != &bmc_device_type)
return 0;
bmc = to_bmc_device(dev);
- rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
+ rv = (bmc->id.product_id == cid->product_id
+ && bmc->id.device_id == cid->device_id);
if (rv)
- return 0;
-
- return (id.product_id == cid->product_id
- && id.device_id == cid->device_id);
+ rv = kref_get_unless_zero(&bmc->usecount);
+ return rv;
}
/*
- * Must be called with ipmidriver_mutex held. Returns with the
- * bmc's usecount incremented, if it is non-NULL.
+ * 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,
@@ -2799,7 +2852,6 @@ static struct bmc_device *ipmi_find_bmc_prod_dev_id(
dev = driver_find_device(drv, NULL, &id, __find_bmc_prod_dev_id);
if (dev) {
bmc = to_bmc_device(dev);
- kref_get(&bmc->usecount);
put_device(dev);
}
return bmc;
@@ -2813,25 +2865,39 @@ release_bmc_device(struct device *dev)
kfree(to_bmc_device(dev));
}
-static void
-cleanup_bmc_device(struct kref *ref)
+static void cleanup_bmc_work(struct work_struct *work)
{
- struct bmc_device *bmc = container_of(ref, struct bmc_device, usecount);
+ struct bmc_device *bmc = container_of(work, struct bmc_device,
+ remove_work);
int id = bmc->pdev.id; /* Unregister overwrites id */
platform_device_unregister(&bmc->pdev);
ida_simple_remove(&ipmi_bmc_ida, id);
}
-static void ipmi_bmc_unregister(ipmi_smi_t intf)
+static void
+cleanup_bmc_device(struct kref *ref)
+{
+ struct bmc_device *bmc = container_of(ref, struct bmc_device, usecount);
+
+ /*
+ * Remove the platform device in a work queue to avoid issues
+ * with removing the device attributes while reading a device
+ * attribute.
+ */
+ schedule_work(&bmc->remove_work);
+}
+
+/*
+ * Must be called with intf->bmc_reg_mutex held.
+ */
+static void __ipmi_bmc_unregister(ipmi_smi_t intf)
{
struct bmc_device *bmc = intf->bmc;
if (!intf->bmc_registered)
return;
- mutex_lock(&intf->bmc_reg_mutex);
-
sysfs_remove_link(&intf->si_dev->kobj, "bmc");
sysfs_remove_link(&bmc->pdev.dev.kobj, intf->my_dev_name);
kfree(intf->my_dev_name);
@@ -2841,32 +2907,48 @@ static void ipmi_bmc_unregister(ipmi_smi_t intf)
list_del(&intf->bmc_link);
mutex_unlock(&bmc->dyn_mutex);
intf->bmc = &intf->tmp_bmc;
- mutex_lock(&ipmidriver_mutex);
kref_put(&bmc->usecount, cleanup_bmc_device);
- mutex_unlock(&ipmidriver_mutex);
intf->bmc_registered = false;
+}
+static void ipmi_bmc_unregister(ipmi_smi_t intf)
+{
+ mutex_lock(&intf->bmc_reg_mutex);
+ __ipmi_bmc_unregister(intf);
mutex_unlock(&intf->bmc_reg_mutex);
}
-static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum)
+/*
+ * Must be called with intf->bmc_reg_mutex held.
+ */
+static int __ipmi_bmc_register(ipmi_smi_t intf,
+ struct ipmi_device_id *id,
+ bool guid_set, u8 *guid, int intf_num)
{
int rv;
struct bmc_device *bmc = intf->bmc;
struct bmc_device *old_bmc;
+ /*
+ * platform_device_register() can cause bmc_reg_mutex to
+ * be claimed because of the is_visible functions of
+ * the attributes. Eliminate possible recursion and
+ * release the lock.
+ */
+ intf->in_bmc_register = true;
+ mutex_unlock(&intf->bmc_reg_mutex);
+
/*
* Try to find if there is an bmc_device struct
* representing the interfaced BMC already
*/
mutex_lock(&ipmidriver_mutex);
- if (bmc->dyn_guid_set)
- old_bmc = ipmi_find_bmc_guid(&ipmidriver.driver, bmc->guid);
+ if (guid_set)
+ old_bmc = ipmi_find_bmc_guid(&ipmidriver.driver, guid);
else
old_bmc = ipmi_find_bmc_prod_dev_id(&ipmidriver.driver,
- bmc->id.product_id,
- bmc->id.device_id);
- mutex_unlock(&ipmidriver_mutex);
+ id->product_id,
+ id->device_id);
/*
* If there is already an bmc_device, free the new one,
@@ -2874,6 +2956,10 @@ static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum)
*/
if (old_bmc) {
bmc = old_bmc;
+ /*
+ * Note: old_bmc already has usecount incremented by
+ * the BMC find functions.
+ */
intf->bmc = old_bmc;
mutex_lock(&bmc->dyn_mutex);
list_add_tail(&intf->bmc_link, &bmc->intfs);
@@ -2893,6 +2979,13 @@ static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum)
}
INIT_LIST_HEAD(&bmc->intfs);
mutex_init(&bmc->dyn_mutex);
+ INIT_WORK(&bmc->remove_work, cleanup_bmc_work);
+
+ bmc->id = *id;
+ bmc->dyn_id_set = 1;
+ bmc->dyn_guid_set = guid_set;
+ memcpy(bmc->guid, guid, 16);
+ bmc->dyn_id_expiry = jiffies + IPMI_DYN_DEV_ID_EXPIRY;
bmc->pdev.name = "ipmi_bmc";
@@ -2938,7 +3031,9 @@ static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum)
goto out_put_bmc;
}
- intf->my_dev_name = kasprintf(GFP_KERNEL, "ipmi%d", ifnum);
+ if (intf_num == -1)
+ intf_num = intf->intf_num;
+ intf->my_dev_name = kasprintf(GFP_KERNEL, "ipmi%d", intf_num);
if (!intf->my_dev_name) {
rv = -ENOMEM;
printk(KERN_ERR
@@ -2962,6 +3057,9 @@ static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum)
intf->bmc_registered = true;
out:
+ mutex_unlock(&ipmidriver_mutex);
+ mutex_lock(&intf->bmc_reg_mutex);
+ intf->in_bmc_register = false;
return rv;
@@ -2977,9 +3075,7 @@ static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum)
list_del(&intf->bmc_link);
mutex_unlock(&bmc->dyn_mutex);
intf->bmc = &intf->tmp_bmc;
- mutex_lock(&ipmidriver_mutex);
kref_put(&bmc->usecount, cleanup_bmc_device);
- mutex_unlock(&ipmidriver_mutex);
goto out;
out_list_del:
@@ -3283,16 +3379,12 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers,
if (rv)
goto out;
- rv = bmc_get_device_id(intf, NULL, &id, NULL, NULL);
+ rv = __bmc_get_device_id(intf, NULL, &id, NULL, NULL, i);
if (rv) {
dev_err(si_dev, "Unable to get the device id: %d\n", rv);
goto out;
}
- rv = ipmi_bmc_register(intf, i);
- if (rv)
- goto out;
-
if (ipmi_version_major(&id) > 1
|| (ipmi_version_major(&id) == 1
&& ipmi_version_minor(&id) >= 5)) {
@@ -3300,6 +3392,7 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers,
* Start scanning the channels to see what is
* available.
*/
+ mutex_lock(&intf->bmc_reg_mutex);
intf->null_user_handler = channel_handler;
intf->curr_channel = 0;
rv = send_channel_info_cmd(intf, 0);
@@ -3314,6 +3407,7 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers,
wait_event(intf->waitq,
intf->curr_channel >= IPMI_MAX_CHANNELS);
intf->null_user_handler = NULL;
+ mutex_unlock(&intf->bmc_reg_mutex);
} else {
/* Assume a single IPMB channel at zero. */
intf->channels[0].medium = IPMI_CHANNEL_MEDIUM_IPMB;
--
2.19.2