From e86ee2d44b44056243da17c120ad258717cedf9b Mon Sep 17 00:00:00 2001
From: Corey Minyard <cminyard@mvista.com>
Date: Thu, 5 Apr 2018 22:05:04 -0500
Subject: [PATCH] ipmi: Rework locking and shutdown for hot remove
Git-commit: e86ee2d44b44056243da17c120ad258717cedf9b
Patch-mainline: v4.18-rc1
References: FATE#326156
To handle hot remove of interfaces, a lot of rework had to be
done to the locking. Several things were switched over to srcu
and shutdown for users and interfaces was added for cleaner
shutdown.
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/char/ipmi/ipmi_msghandler.c | 486 ++++++++++++++++++++----------------
1 file changed, 278 insertions(+), 208 deletions(-)
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -197,8 +197,12 @@ MODULE_PARM_DESC(default_max_retries,
struct ipmi_user {
struct list_head link;
- /* Set to false when the user is destroyed. */
- bool valid;
+ /*
+ * Set to NULL when the user is destroyed, a pointer to myself
+ * so srcu_dereference can be used on it.
+ */
+ struct ipmi_user *self;
+ struct srcu_struct release_barrier;
struct kref refcount;
@@ -213,6 +217,23 @@ struct ipmi_user {
bool gets_events;
};
+static struct ipmi_user *acquire_ipmi_user(struct ipmi_user *user, int *index)
+ __acquires(user->release_barrier)
+{
+ struct ipmi_user *ruser;
+
+ *index = srcu_read_lock(&user->release_barrier);
+ ruser = srcu_dereference(user->self, &user->release_barrier);
+ if (!ruser)
+ srcu_read_unlock(&user->release_barrier, *index);
+ return ruser;
+}
+
+static void release_ipmi_user(struct ipmi_user *user, int index)
+{
+ srcu_read_unlock(&user->release_barrier, index);
+}
+
struct cmd_rcvr {
struct list_head link;
@@ -444,10 +465,11 @@ struct ipmi_smi {
struct list_head link;
/*
- * The list of upper layers that are using me. seq_lock
- * protects this.
+ * The list of upper layers that are using me. seq_lock write
+ * protects this. Read protection is with srcu.
*/
struct list_head users;
+ struct srcu_struct users_srcu;
/* Used for wake ups at startup. */
wait_queue_head_t waitq;
@@ -467,12 +489,6 @@ struct ipmi_smi {
bool in_bmc_register; /* Handle recursive situations. Yuck. */
struct work_struct bmc_reg_work;
- /*
- * This is the lower-layer's sender routine. Note that you
- * must either be holding the ipmi_interfaces_mutex or be in
- * an umpreemptible region to use this. You must fetch the
- * value into a local variable and make sure it is not NULL.
- */
const struct ipmi_smi_handlers *handlers;
void *send_info;
@@ -616,6 +632,7 @@ static DEFINE_MUTEX(ipmidriver_mutex);
static LIST_HEAD(ipmi_interfaces);
static DEFINE_MUTEX(ipmi_interfaces_mutex);
+DEFINE_STATIC_SRCU(ipmi_interfaces_srcu);
/*
* List of watchers that want to know when smi's are added and deleted.
@@ -716,58 +733,32 @@ static void intf_free(struct kref *ref)
struct watcher_entry {
int intf_num;
- struct ipmi_smi *intf;
+ struct ipmi_smi *intf;
struct list_head link;
};
int ipmi_smi_watcher_register(struct ipmi_smi_watcher *watcher)
{
struct ipmi_smi *intf;
- LIST_HEAD(to_deliver);
- struct watcher_entry *e, *e2;
+ int index;
mutex_lock(&smi_watchers_mutex);
- mutex_lock(&ipmi_interfaces_mutex);
-
- /* Build a list of things to deliver. */
- list_for_each_entry(intf, &ipmi_interfaces, link) {
- if (intf->intf_num == -1)
- continue;
- e = kmalloc(sizeof(*e), GFP_KERNEL);
- if (!e)
- goto out_err;
- kref_get(&intf->refcount);
- e->intf = intf;
- e->intf_num = intf->intf_num;
- list_add_tail(&e->link, &to_deliver);
- }
-
- /* We will succeed, so add it to the list. */
list_add(&watcher->link, &smi_watchers);
- mutex_unlock(&ipmi_interfaces_mutex);
+ index = srcu_read_lock(&ipmi_interfaces_srcu);
+ list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
+ int intf_num = READ_ONCE(intf->intf_num);
- list_for_each_entry_safe(e, e2, &to_deliver, link) {
- list_del(&e->link);
- watcher->new_smi(e->intf_num, e->intf->si_dev);
- kref_put(&e->intf->refcount, intf_free);
- kfree(e);
+ if (intf_num == -1)
+ continue;
+ watcher->new_smi(intf_num, intf->si_dev);
}
+ srcu_read_unlock(&ipmi_interfaces_srcu, index);
mutex_unlock(&smi_watchers_mutex);
return 0;
-
- out_err:
- mutex_unlock(&ipmi_interfaces_mutex);
- mutex_unlock(&smi_watchers_mutex);
- list_for_each_entry_safe(e, e2, &to_deliver, link) {
- list_del(&e->link);
- kref_put(&e->intf->refcount, intf_free);
- kfree(e);
- }
- return -ENOMEM;
}
EXPORT_SYMBOL(ipmi_smi_watcher_register);
@@ -788,12 +779,14 @@ call_smi_watchers(int i, struct device *
{
struct ipmi_smi_watcher *w;
+ mutex_lock(&smi_watchers_mutex);
list_for_each_entry(w, &smi_watchers, link) {
if (try_module_get(w->owner)) {
w->new_smi(i, dev);
module_put(w->owner);
}
}
+ mutex_unlock(&smi_watchers_mutex);
}
static int
@@ -906,9 +899,17 @@ static int deliver_response(struct ipmi_
* receive handler doesn't much meaning and has a deadlock
* risk. At this moment, simply skip it in that case.
*/
+ int index;
+ struct ipmi_user *user = acquire_ipmi_user(msg->user, &index);
- struct ipmi_user *user = msg->user;
- user->handler->ipmi_recv_hndl(msg, user->handler_data);
+ if (user) {
+ user->handler->ipmi_recv_hndl(msg, user->handler_data);
+ release_ipmi_user(msg->user, index);
+ } else {
+ /* User went away, give up. */
+ ipmi_free_recv_msg(msg);
+ rv = -EINVAL;
+ }
}
return rv;
@@ -1095,7 +1096,7 @@ int ipmi_create_user(unsigned int
{
unsigned long flags;
struct ipmi_user *new_user;
- int rv = 0;
+ int rv = 0, index;
struct ipmi_smi *intf;
/*
@@ -1130,7 +1131,7 @@ int ipmi_create_user(unsigned int
if (!new_user)
return -ENOMEM;
- mutex_lock(&ipmi_interfaces_mutex);
+ index = srcu_read_lock(&ipmi_interfaces_srcu);
list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
if (intf->intf_num == if_num)
goto found;
@@ -1140,6 +1141,10 @@ int ipmi_create_user(unsigned int
goto out_kfree;
found:
+ rv = init_srcu_struct(&new_user->release_barrier);
+ if (rv)
+ goto out_kfree;
+
/* Note that each existing user holds a refcount to the interface. */
kref_get(&intf->refcount);
@@ -1149,26 +1154,7 @@ int ipmi_create_user(unsigned int
new_user->intf = intf;
new_user->gets_events = false;
- if (!try_module_get(intf->handlers->owner)) {
- rv = -ENODEV;
- goto out_kref;
- }
-
- if (intf->handlers->inc_usecount) {
- rv = intf->handlers->inc_usecount(intf->send_info);
- if (rv) {
- module_put(intf->handlers->owner);
- goto out_kref;
- }
- }
-
- /*
- * Hold the lock so intf->handlers is guaranteed to be good
- * until now
- */
- mutex_unlock(&ipmi_interfaces_mutex);
-
- new_user->valid = true;
+ rcu_assign_pointer(new_user->self, new_user);
spin_lock_irqsave(&intf->seq_lock, flags);
list_add_rcu(&new_user->link, &intf->users);
spin_unlock_irqrestore(&intf->seq_lock, flags);
@@ -1177,13 +1163,12 @@ int ipmi_create_user(unsigned int
if (atomic_inc_return(&intf->event_waiters) == 1)
need_waiter(intf);
}
+ srcu_read_unlock(&ipmi_interfaces_srcu, index);
*user = new_user;
return 0;
-out_kref:
- kref_put(&intf->refcount, intf_free);
out_kfree:
- mutex_unlock(&ipmi_interfaces_mutex);
+ srcu_read_unlock(&ipmi_interfaces_srcu, index);
kfree(new_user);
return rv;
}
@@ -1191,26 +1176,25 @@ EXPORT_SYMBOL(ipmi_create_user);
int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *data)
{
- int rv = 0;
+ int rv, index;
struct ipmi_smi *intf;
- const struct ipmi_smi_handlers *handlers;
- mutex_lock(&ipmi_interfaces_mutex);
+ index = srcu_read_lock(&ipmi_interfaces_srcu);
list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
if (intf->intf_num == if_num)
goto found;
}
+ srcu_read_unlock(&ipmi_interfaces_srcu, index);
+
/* Not found, return an error */
- rv = -EINVAL;
- mutex_unlock(&ipmi_interfaces_mutex);
- return rv;
+ return -EINVAL;
found:
- handlers = intf->handlers;
- rv = -ENOSYS;
- if (handlers->get_smi_info)
- rv = handlers->get_smi_info(intf->send_info, data);
- mutex_unlock(&ipmi_interfaces_mutex);
+ if (!intf->handlers->get_smi_info)
+ rv = -ENOTTY;
+ else
+ rv = intf->handlers->get_smi_info(intf->send_info, data);
+ srcu_read_unlock(&ipmi_interfaces_srcu, index);
return rv;
}
@@ -1222,7 +1206,7 @@ static void free_user(struct kref *ref)
kfree(user);
}
-int ipmi_destroy_user(struct ipmi_user *user)
+static void _ipmi_destroy_user(struct ipmi_user *user)
{
struct ipmi_smi *intf = user->intf;
int i;
@@ -1230,7 +1214,22 @@ int ipmi_destroy_user(struct ipmi_user *
struct cmd_rcvr *rcvr;
struct cmd_rcvr *rcvrs = NULL;
- user->valid = false;
+ if (!acquire_ipmi_user(user, &i)) {
+ /*
+ * The user has already been cleaned up, just make sure
+ * nothing is using it and return.
+ */
+ synchronize_srcu(&user->release_barrier);
+ return;
+ }
+
+ rcu_assign_pointer(user->self, NULL);
+ release_ipmi_user(user, i);
+
+ synchronize_srcu(&user->release_barrier);
+
+ if (user->handler->shutdown)
+ user->handler->shutdown(user->handler_data);
if (user->handler->ipmi_watchdog_pretimeout)
atomic_dec(&intf->event_waiters);
@@ -1255,7 +1254,7 @@ int ipmi_destroy_user(struct ipmi_user *
* Remove the user from the command receiver's table. First
* we build a list of everything (not using the standard link,
* since other things may be using it till we do
- * synchronize_rcu()) then free everything in that list.
+ * synchronize_srcu()) then free everything in that list.
*/
mutex_lock(&intf->cmd_rcvrs_mutex);
list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
@@ -1273,16 +1272,14 @@ int ipmi_destroy_user(struct ipmi_user *
kfree(rcvr);
}
- mutex_lock(&ipmi_interfaces_mutex);
- if (intf->handlers) {
- module_put(intf->handlers->owner);
- if (intf->handlers->dec_usecount)
- intf->handlers->dec_usecount(intf->send_info);
- }
- mutex_unlock(&ipmi_interfaces_mutex);
-
kref_put(&intf->refcount, intf_free);
+}
+int ipmi_destroy_user(struct ipmi_user *user)
+{
+ _ipmi_destroy_user(user);
+
+ cleanup_srcu_struct(&user->release_barrier);
kref_put(&user->refcount, free_user);
return 0;
@@ -1294,16 +1291,20 @@ int ipmi_get_version(struct ipmi_user *u
unsigned char *minor)
{
struct ipmi_device_id id;
- int rv;
+ int rv, index;
- rv = bmc_get_device_id(user->intf, NULL, &id, NULL, NULL);
- if (rv)
- return rv;
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
- *major = ipmi_version_major(&id);
- *minor = ipmi_version_minor(&id);
+ rv = bmc_get_device_id(user->intf, NULL, &id, NULL, NULL);
+ if (!rv) {
+ *major = ipmi_version_major(&id);
+ *minor = ipmi_version_minor(&id);
+ }
+ release_ipmi_user(user, index);
- return 0;
+ return rv;
}
EXPORT_SYMBOL(ipmi_get_version);
@@ -1311,9 +1312,17 @@ int ipmi_set_my_address(struct ipmi_user
unsigned int channel,
unsigned char address)
{
+ int index;
+
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
+
if (channel >= IPMI_MAX_CHANNELS)
return -EINVAL;
user->intf->addrinfo[channel].address = address;
+ release_ipmi_user(user, index);
+
return 0;
}
EXPORT_SYMBOL(ipmi_set_my_address);
@@ -1322,9 +1331,17 @@ int ipmi_get_my_address(struct ipmi_user
unsigned int channel,
unsigned char *address)
{
+ int index;
+
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
+
if (channel >= IPMI_MAX_CHANNELS)
return -EINVAL;
*address = user->intf->addrinfo[channel].address;
+ release_ipmi_user(user, index);
+
return 0;
}
EXPORT_SYMBOL(ipmi_get_my_address);
@@ -1333,9 +1350,17 @@ int ipmi_set_my_LUN(struct ipmi_user *us
unsigned int channel,
unsigned char LUN)
{
+ int index;
+
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
+
if (channel >= IPMI_MAX_CHANNELS)
return -EINVAL;
user->intf->addrinfo[channel].lun = LUN & 0x3;
+ release_ipmi_user(user, index);
+
return 0;
}
EXPORT_SYMBOL(ipmi_set_my_LUN);
@@ -1344,21 +1369,34 @@ int ipmi_get_my_LUN(struct ipmi_user *us
unsigned int channel,
unsigned char *address)
{
+ int index;
+
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
+
if (channel >= IPMI_MAX_CHANNELS)
return -EINVAL;
*address = user->intf->addrinfo[channel].lun;
+ release_ipmi_user(user, index);
+
return 0;
}
EXPORT_SYMBOL(ipmi_get_my_LUN);
int ipmi_get_maintenance_mode(struct ipmi_user *user)
{
- int mode;
+ int mode, index;
unsigned long flags;
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
+
spin_lock_irqsave(&user->intf->maintenance_mode_lock, flags);
mode = user->intf->maintenance_mode;
spin_unlock_irqrestore(&user->intf->maintenance_mode_lock, flags);
+ release_ipmi_user(user, index);
return mode;
}
@@ -1373,10 +1411,14 @@ static void maintenance_mode_update(stru
int ipmi_set_maintenance_mode(struct ipmi_user *user, int mode)
{
- int rv = 0;
+ int rv = 0, index;
unsigned long flags;
struct ipmi_smi *intf = user->intf;
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
+
spin_lock_irqsave(&intf->maintenance_mode_lock, flags);
if (intf->maintenance_mode != mode) {
switch (mode) {
@@ -1403,6 +1445,7 @@ int ipmi_set_maintenance_mode(struct ipm
}
out_unlock:
spin_unlock_irqrestore(&intf->maintenance_mode_lock, flags);
+ release_ipmi_user(user, index);
return rv;
}
@@ -1414,6 +1457,11 @@ int ipmi_set_gets_events(struct ipmi_use
struct ipmi_smi *intf = user->intf;
struct ipmi_recv_msg *msg, *msg2;
struct list_head msgs;
+ int index;
+
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
INIT_LIST_HEAD(&msgs);
@@ -1463,6 +1511,7 @@ int ipmi_set_gets_events(struct ipmi_use
out:
spin_unlock_irqrestore(&intf->events_lock, flags);
+ release_ipmi_user(user, index);
return 0;
}
@@ -1505,8 +1554,11 @@ int ipmi_register_for_cmd(struct ipmi_us
{
struct ipmi_smi *intf = user->intf;
struct cmd_rcvr *rcvr;
- int rv = 0;
+ int rv = 0, index;
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
rcvr = kmalloc(sizeof(*rcvr), GFP_KERNEL);
if (!rcvr)
@@ -1532,6 +1584,7 @@ int ipmi_register_for_cmd(struct ipmi_us
mutex_unlock(&intf->cmd_rcvrs_mutex);
if (rv)
kfree(rcvr);
+ release_ipmi_user(user, index);
return rv;
}
@@ -1545,7 +1598,11 @@ int ipmi_unregister_for_cmd(struct ipmi_
struct ipmi_smi *intf = user->intf;
struct cmd_rcvr *rcvr;
struct cmd_rcvr *rcvrs = NULL;
- int i, rv = -ENOENT;
+ int i, rv = -ENOENT, index;
+
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
mutex_lock(&intf->cmd_rcvrs_mutex);
for (i = 0; i < IPMI_NUM_CHANNELS; i++) {
@@ -1566,12 +1623,14 @@ int ipmi_unregister_for_cmd(struct ipmi_
}
mutex_unlock(&intf->cmd_rcvrs_mutex);
synchronize_rcu();
+ release_ipmi_user(user, index);
while (rcvrs) {
atomic_dec(&intf->event_waiters);
rcvr = rcvrs;
rcvrs = rcvr->next;
kfree(rcvr);
}
+
return rv;
}
EXPORT_SYMBOL(ipmi_unregister_for_cmd);
@@ -2066,8 +2125,10 @@ static int i_ipmi_request(struct ipmi_us
recv_msg = supplied_recv;
else {
recv_msg = ipmi_alloc_recv_msg();
- if (recv_msg == NULL)
- return -ENOMEM;
+ if (recv_msg == NULL) {
+ rv = -ENOMEM;
+ goto out;
+ }
}
recv_msg->user_msg_data = user_msg_data;
@@ -2077,7 +2138,8 @@ static int i_ipmi_request(struct ipmi_us
smi_msg = ipmi_alloc_smi_msg();
if (smi_msg == NULL) {
ipmi_free_recv_msg(recv_msg);
- return -ENOMEM;
+ rv = -ENOMEM;
+ goto out;
}
}
@@ -2089,6 +2151,7 @@ static int i_ipmi_request(struct ipmi_us
recv_msg->user = user;
if (user)
+ /* The put happens when the message is freed. */
kref_get(&user->refcount);
recv_msg->msgid = msgid;
/*
@@ -2124,6 +2187,7 @@ out_err:
}
rcu_read_unlock();
+out:
return rv;
}
@@ -2149,25 +2213,32 @@ int ipmi_request_settime(struct ipmi_use
unsigned int retry_time_ms)
{
unsigned char saddr = 0, lun = 0;
- int rv;
+ int rv, index;
if (!user)
return -EINVAL;
+
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
+
rv = check_addr(user->intf, addr, &saddr, &lun);
- if (rv)
- return rv;
- return i_ipmi_request(user,
- user->intf,
- addr,
- msgid,
- msg,
- user_msg_data,
- NULL, NULL,
- priority,
- saddr,
- lun,
- retries,
- retry_time_ms);
+ if (!rv)
+ rv = i_ipmi_request(user,
+ user->intf,
+ addr,
+ msgid,
+ msg,
+ user_msg_data,
+ NULL, NULL,
+ priority,
+ saddr,
+ lun,
+ retries,
+ retry_time_ms);
+
+ release_ipmi_user(user, index);
+ return rv;
}
EXPORT_SYMBOL(ipmi_request_settime);
@@ -2181,25 +2252,32 @@ int ipmi_request_supply_msgs(struct ipmi
int priority)
{
unsigned char saddr = 0, lun = 0;
- int rv;
+ int rv, index;
if (!user)
return -EINVAL;
+
+ user = acquire_ipmi_user(user, &index);
+ if (!user)
+ return -ENODEV;
+
rv = check_addr(user->intf, addr, &saddr, &lun);
- if (rv)
- return rv;
- return i_ipmi_request(user,
- user->intf,
- addr,
- msgid,
- msg,
- user_msg_data,
- supplied_smi,
- supplied_recv,
- priority,
- saddr,
- lun,
- -1, 0);
+ if (!rv)
+ rv = i_ipmi_request(user,
+ user->intf,
+ addr,
+ msgid,
+ msg,
+ user_msg_data,
+ supplied_smi,
+ supplied_recv,
+ priority,
+ saddr,
+ lun,
+ -1, 0);
+
+ release_ipmi_user(user, index);
+ return rv;
}
EXPORT_SYMBOL(ipmi_request_supply_msgs);
@@ -3463,6 +3541,13 @@ int ipmi_register_smi(const struct ipmi_
if (!intf)
return -ENOMEM;
+ rv = init_srcu_struct(&intf->users_srcu);
+ if (rv) {
+ kfree(intf);
+ return rv;
+ }
+
+
intf->bmc = &intf->tmp_bmc;
INIT_LIST_HEAD(&intf->bmc->intfs);
mutex_init(&intf->bmc->dyn_mutex);
@@ -3513,7 +3598,6 @@ int ipmi_register_smi(const struct ipmi_
intf->proc_dir = NULL;
- mutex_lock(&smi_watchers_mutex);
mutex_lock(&ipmi_interfaces_mutex);
/* Look for a hole in the numbers. */
i = 0;
@@ -3554,11 +3638,10 @@ int ipmi_register_smi(const struct ipmi_
ipmi_bmc_unregister(intf);
if (intf->proc_dir)
remove_proc_entries(intf);
- intf->handlers = NULL;
list_del_rcu(&intf->link);
mutex_unlock(&ipmi_interfaces_mutex);
- mutex_unlock(&smi_watchers_mutex);
- synchronize_rcu();
+ synchronize_srcu(&ipmi_interfaces_srcu);
+ cleanup_srcu_struct(&intf->users_srcu);
kref_put(&intf->refcount, intf_free);
} else {
/*
@@ -3569,9 +3652,9 @@ int ipmi_register_smi(const struct ipmi_
smp_wmb();
intf->intf_num = i;
mutex_unlock(&ipmi_interfaces_mutex);
+
/* After this point the interface is legal to use. */
call_smi_watchers(i, intf->si_dev);
- mutex_unlock(&smi_watchers_mutex);
}
return rv;
@@ -3633,43 +3716,47 @@ static void cleanup_smi_msgs(struct ipmi
int ipmi_unregister_smi(struct ipmi_smi *intf)
{
struct ipmi_smi_watcher *w;
- int intf_num = intf->intf_num;
- struct ipmi_user *user;
+ int intf_num = intf->intf_num, index;
- mutex_lock(&smi_watchers_mutex);
mutex_lock(&ipmi_interfaces_mutex);
intf->intf_num = -1;
intf->in_shutdown = true;
list_del_rcu(&intf->link);
mutex_unlock(&ipmi_interfaces_mutex);
- synchronize_rcu();
+ synchronize_srcu(&ipmi_interfaces_srcu);
- cleanup_smi_msgs(intf);
-
- /* Clean up the effects of users on the lower-level software. */
- mutex_lock(&ipmi_interfaces_mutex);
- rcu_read_lock();
- list_for_each_entry_rcu(user, &intf->users, link) {
- module_put(intf->handlers->owner);
- if (intf->handlers->dec_usecount)
- intf->handlers->dec_usecount(intf->send_info);
- }
- rcu_read_unlock();
- intf->handlers = NULL;
- mutex_unlock(&ipmi_interfaces_mutex);
-
- remove_proc_entries(intf);
- ipmi_bmc_unregister(intf);
+ /* At this point no users can be added to the interface. */
/*
* Call all the watcher interfaces to tell them that
- * an interface is gone.
+ * an interface is going away.
*/
+ mutex_lock(&smi_watchers_mutex);
list_for_each_entry(w, &smi_watchers, link)
w->smi_gone(intf_num);
mutex_unlock(&smi_watchers_mutex);
+ index = srcu_read_lock(&intf->users_srcu);
+ while (!list_empty(&intf->users)) {
+ struct ipmi_user *user =
+ container_of(list_next_rcu(&intf->users),
+ struct ipmi_user, link);
+
+ _ipmi_destroy_user(user);
+ }
+ srcu_read_unlock(&intf->users_srcu, index);
+
+ if (intf->handlers->shutdown)
+ intf->handlers->shutdown(intf->send_info);
+
+ cleanup_smi_msgs(intf);
+
+ remove_proc_entries(intf);
+ ipmi_bmc_unregister(intf);
+
+ cleanup_srcu_struct(&intf->users_srcu);
kref_put(&intf->refcount, intf_free);
+
return 0;
}
EXPORT_SYMBOL(ipmi_unregister_smi);
@@ -4141,8 +4228,7 @@ static int handle_read_event_rsp(struct
struct ipmi_recv_msg *recv_msg, *recv_msg2;
struct list_head msgs;
struct ipmi_user *user;
- int rv = 0;
- int deliver_count = 0;
+ int rv = 0, deliver_count = 0, index;
unsigned long flags;
if (msg->rsp_size < 19) {
@@ -4166,7 +4252,7 @@ static int handle_read_event_rsp(struct
* Allocate and fill in one message for every user that is
* getting events.
*/
- rcu_read_lock();
+ index = srcu_read_lock(&intf->users_srcu);
list_for_each_entry_rcu(user, &intf->users, link) {
if (!user->gets_events)
continue;
@@ -4195,7 +4281,7 @@ static int handle_read_event_rsp(struct
kref_get(&user->refcount);
list_add_tail(&recv_msg->link, &msgs);
}
- rcu_read_unlock();
+ srcu_read_unlock(&intf->users_srcu, index);
if (deliver_count) {
/* Now deliver all the messages. */
@@ -4242,7 +4328,7 @@ static int handle_bmc_rsp(struct ipmi_sm
struct ipmi_smi_msg *msg)
{
struct ipmi_recv_msg *recv_msg;
- struct ipmi_user *user;
+ struct ipmi_system_interface_addr *smi_addr;
recv_msg = (struct ipmi_recv_msg *) msg->user_data;
if (recv_msg == NULL) {
@@ -4251,30 +4337,19 @@ static int handle_bmc_rsp(struct ipmi_sm
return 0;
}
- user = recv_msg->user;
- /* Make sure the user still exists. */
- if (user && !user->valid) {
- /* The user for the message went away, so give up. */
- ipmi_inc_stat(intf, unhandled_local_responses);
- ipmi_free_recv_msg(recv_msg);
- } else {
- struct ipmi_system_interface_addr *smi_addr;
-
- ipmi_inc_stat(intf, handled_local_responses);
- recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
- recv_msg->msgid = msg->msgid;
- smi_addr = ((struct ipmi_system_interface_addr *)
- &recv_msg->addr);
- smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
- smi_addr->channel = IPMI_BMC_CHANNEL;
- smi_addr->lun = msg->rsp[0] & 3;
- recv_msg->msg.netfn = msg->rsp[0] >> 2;
- recv_msg->msg.cmd = msg->rsp[1];
- memcpy(recv_msg->msg_data, &msg->rsp[2], msg->rsp_size - 2);
- recv_msg->msg.data = recv_msg->msg_data;
- recv_msg->msg.data_len = msg->rsp_size - 2;
- deliver_local_response(intf, recv_msg);
- }
+ recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
+ recv_msg->msgid = msg->msgid;
+ smi_addr = ((struct ipmi_system_interface_addr *)
+ &recv_msg->addr);
+ smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+ smi_addr->channel = IPMI_BMC_CHANNEL;
+ smi_addr->lun = msg->rsp[0] & 3;
+ recv_msg->msg.netfn = msg->rsp[0] >> 2;
+ recv_msg->msg.cmd = msg->rsp[1];
+ memcpy(recv_msg->msg_data, &msg->rsp[2], msg->rsp_size - 2);
+ recv_msg->msg.data = recv_msg->msg_data;
+ recv_msg->msg.data_len = msg->rsp_size - 2;
+ deliver_local_response(intf, recv_msg);
return 0;
}
@@ -4327,7 +4402,7 @@ static int handle_one_recv_msg(struct ip
* It's a response to a response we sent. For this we
* deliver a send message response to the user.
*/
- struct ipmi_recv_msg *recv_msg = msg->user_data;
+ struct ipmi_recv_msg *recv_msg = msg->user_data;
requeue = 0;
if (msg->rsp_size < 2)
@@ -4342,10 +4417,6 @@ static int handle_one_recv_msg(struct ip
if (!recv_msg)
goto out;
- /* Make sure the user still exists. */
- if (!recv_msg->user || !recv_msg->user->valid)
- goto out;
-
recv_msg->recv_type = IPMI_RESPONSE_RESPONSE_TYPE;
recv_msg->msg.data = recv_msg->msg_data;
recv_msg->msg.data_len = 1;
@@ -4488,14 +4559,15 @@ static void handle_new_recv_msgs(struct
*/
if (atomic_add_unless(&intf->watchdog_pretimeouts_to_deliver, -1, 0)) {
struct ipmi_user *user;
+ int index;
- rcu_read_lock();
+ index = srcu_read_lock(&intf->users_srcu);
list_for_each_entry_rcu(user, &intf->users, link) {
if (user->handler->ipmi_watchdog_pretimeout)
user->handler->ipmi_watchdog_pretimeout(
user->handler_data);
}
- rcu_read_unlock();
+ srcu_read_unlock(&intf->users_srcu, index);
}
}
@@ -4662,8 +4734,7 @@ static void check_msg_timeout(struct ipm
int slot, unsigned long *flags,
unsigned int *waiting_msgs)
{
- struct ipmi_recv_msg *msg;
- const struct ipmi_smi_handlers *handlers;
+ struct ipmi_recv_msg *msg;
if (intf->in_shutdown)
return;
@@ -4721,8 +4792,7 @@ static void check_msg_timeout(struct ipm
* only for messages to the local MC, which don't get
* resent.
*/
- handlers = intf->handlers;
- if (handlers) {
+ if (intf->handlers) {
if (is_lan_addr(&ent->recv_msg->addr))
ipmi_inc_stat(intf,
retransmitted_lan_commands);
@@ -4730,7 +4800,7 @@ static void check_msg_timeout(struct ipm
ipmi_inc_stat(intf,
retransmitted_ipmb_commands);
- smi_send(intf, handlers, smi_msg, 0);
+ smi_send(intf, intf->handlers, smi_msg, 0);
} else
ipmi_free_smi_msg(smi_msg);
@@ -4822,12 +4892,12 @@ static atomic_t stop_operation;
static void ipmi_timeout(unsigned long data)
{
struct ipmi_smi *intf;
- int nt = 0;
+ int nt = 0, index;
if (atomic_read(&stop_operation))
return;
- rcu_read_lock();
+ index = srcu_read_lock(&ipmi_interfaces_srcu);
list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
int lnt = 0;
@@ -4850,7 +4920,7 @@ static void ipmi_timeout(unsigned long d
nt += lnt;
}
- rcu_read_unlock();
+ srcu_read_unlock(&ipmi_interfaces_srcu, index);
if (nt)
mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);