[PATCH v2 1/4] ipmi: msghandler: Add a limit for the number of users

[PATCH v2 1/4] ipmi: msghandler: Add a limit for the number of users

[Chen Guanqiao]

The administrator sets the limit for the number of users by modifying
/sys/module/ipmi_msghandler/parameters/default_max_users.

Signed-off-by: Chen Guanqiao <chen.chenchacha@foxmail.com>
---
 drivers/char/ipmi/ipmi_msghandler.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index c59265146e9c..7886c8337368 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -145,6 +145,12 @@ module_param(default_max_retries, uint, 0644);
 MODULE_PARM_DESC(default_max_retries,
 		 "The time (milliseconds) between retry sends in maintenance mode");

+/* The default maximum number of users per intf */
+static unsigned int default_max_users = 50;
+module_param(default_max_users, uint, 0644);
+MODULE_PARM_DESC(default_max_users,
+		 "The maximum number of users per interface");
+
 /* Call every ~1000 ms. */
 #define IPMI_TIMEOUT_TIME	1000

@@ -579,6 +585,9 @@ struct ipmi_smi {

 	atomic_t stats[IPMI_NUM_STATS];

+	/* The number of user in this interface */
+	atomic_t user_count;
+
 	/*
 	 * run_to_completion duplicate of smb_info, smi_info
 	 * and ipmi_serial_info structures. Used to decrease numbers of
@@ -1182,9 +1191,11 @@ static void free_user_work(struct work_struct *work)
 {
 	struct ipmi_user *user = container_of(work, struct ipmi_user,
 					      remove_work);
+	struct ipmi_smi *intf = user->intf;

 	cleanup_srcu_struct(&user->release_barrier);
 	vfree(user);
+	atomic_dec(&intf->user_count);
 }

 int ipmi_create_user(unsigned int          if_num,
@@ -1230,6 +1241,12 @@ int ipmi_create_user(unsigned int          if_num,
 	goto out_kfree;

  found:
+	if (atomic_inc_return(&intf->user_count) > default_max_users) {
+		atomic_dec(&intf->user_count);
+		rv = -EBUSY;
+		goto out_kfree;
+	}
+
 	INIT_WORK(&new_user->remove_work, free_user_work);

 	rv = init_srcu_struct(&new_user->release_barrier);
@@ -3548,6 +3565,7 @@ int ipmi_add_smi(struct module         *owner,
 	spin_lock_init(&intf->events_lock);
 	spin_lock_init(&intf->watch_lock);
 	atomic_set(&intf->event_waiters, 0);
+	atomic_set(&intf->user_count, 0);
 	intf->ticks_to_req_ev = IPMI_REQUEST_EV_TIME;
 	INIT_LIST_HEAD(&intf->waiting_events);
 	intf->waiting_events_count = 0;
--
2.25.1

[PATCH v2 2/4] ipmi: msghandler: Add a limit for the number of messages

[Chen Guanqiao]

The administrator sets the limit for the number of messages by modifying
/sys/module/ipmi_msghandler/parameters/default_max_msgs.

Before create a message, count the number of outstanding messages, if
the number reaches the limit, it will return a busy.

Signed-off-by: Chen Guanqiao <chen.chenchacha@foxmail.com>
---
 drivers/char/ipmi/ipmi_msghandler.c | 37 +++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 7886c8337368..80ab88702c5f 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -151,6 +151,12 @@ module_param(default_max_users, uint, 0644);
 MODULE_PARM_DESC(default_max_users,
 		 "The maximum number of users per interface");

+/* The default maximum number of outstanding messages per intf */
+static unsigned int default_max_messages = 100;
+module_param(default_max_messages, uint, 0644);
+MODULE_PARM_DESC(default_max_messages,
+		 "The maximum number of outstanding messages per interface");
+
 /* Call every ~1000 ms. */
 #define IPMI_TIMEOUT_TIME	1000

@@ -916,6 +922,30 @@ unsigned int ipmi_addr_length(int addr_type)
 }
 EXPORT_SYMBOL(ipmi_addr_length);

+static void intf_msg_count(struct ipmi_smi *intf,
+			   unsigned int *hp_count, unsigned int *count)
+{
+	struct ipmi_smi_msg *msg;
+	unsigned long flags;
+	int hp_msg_count = 0, msg_count = 0;
+	int run_to_completion = intf->run_to_completion;
+
+	if (!run_to_completion)
+		spin_lock_irqsave(&intf->xmit_msgs_lock, flags);
+	if (!intf->in_shutdown) {
+		list_for_each_entry(msg, &intf->hp_xmit_msgs, link)
+			hp_msg_count++;
+
+		list_for_each_entry(msg, &intf->xmit_msgs, link)
+			msg_count++;
+	}
+	if (!run_to_completion)
+		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
+
+	*hp_count = hp_msg_count;
+	*count = msg_count;
+}
+
 static int deliver_response(struct ipmi_smi *intf, struct ipmi_recv_msg *msg)
 {
 	int rv = 0;
@@ -2299,6 +2329,7 @@ static int i_ipmi_request(struct ipmi_user     *user,
 {
 	struct ipmi_smi_msg *smi_msg;
 	struct ipmi_recv_msg *recv_msg;
+	unsigned hp_msg_count, msg_count;
 	int rv = 0;

 	if (supplied_recv)
@@ -2330,6 +2361,12 @@ static int i_ipmi_request(struct ipmi_user     *user,
 		goto out_err;
 	}

+	intf_msg_count(intf, &hp_msg_count, &msg_count);
+	if ((hp_msg_count + msg_count) > default_max_messages) {
+		rv = -EBUSY;
+		goto out_err;
+	}
+
 	recv_msg->user = user;
 	if (user)
 		/* The put happens when the message is freed. */
--
2.25.1

[PATCH v2 3/4] ipmi: msghandler: Get the number of users and messages through sysfs

[Chen Guanqiao]

The administrator reads the user_count and msg_count file
corresponding the ipmi device, ipmi traverse all intf, and count
the number of users and messages.

Signed-off-by: Chen Guanqiao <chen.chenchacha@foxmail.com>
---
 drivers/char/ipmi/ipmi_msghandler.c | 71 +++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 80ab88702c5f..a188dc7e7135 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -922,6 +922,19 @@ unsigned int ipmi_addr_length(int addr_type)
 }
 EXPORT_SYMBOL(ipmi_addr_length);

+static unsigned int intf_user_count(struct ipmi_smi *intf)
+{
+	struct ipmi_user *user;
+	int index, count = 0;
+
+	index = srcu_read_lock(&intf->users_srcu);
+	list_for_each_entry_rcu(user, &intf->users, link)
+		count++;
+	srcu_read_unlock(&intf->users_srcu, index);
+
+	return count;
+}
+
 static void intf_msg_count(struct ipmi_smi *intf,
 			   unsigned int *hp_count, unsigned int *count)
 {
@@ -2760,6 +2773,42 @@ static int bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc,
 	return __bmc_get_device_id(intf, bmc, id, guid_set, guid, -1);
 }

+static unsigned int get_user_count(void)
+{
+	struct ipmi_smi *intf;
+	int index;
+	unsigned int count = 0;
+
+	index = srcu_read_lock(&ipmi_interfaces_srcu);
+	list_for_each_entry_rcu(intf, &ipmi_interfaces, link)
+		count += intf_user_count(intf);
+	srcu_read_unlock(&ipmi_interfaces_srcu, index);
+
+	return count;
+}
+
+static void get_msg_count(unsigned int *hp_count, unsigned int *count)
+{
+	struct ipmi_smi *intf;
+	int index;
+
+	*hp_count = 0;
+	*count = 0;
+
+	index = srcu_read_lock(&ipmi_interfaces_srcu);
+	list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
+		int hp_msg_count = 0, msg_count = 0;
+
+		rcu_read_lock();
+		intf_msg_count(intf, &hp_msg_count, &msg_count);
+		rcu_read_unlock();
+
+		*hp_count += hp_msg_count;
+		*count += msg_count;
+	}
+	srcu_read_unlock(&ipmi_interfaces_srcu, index);
+}
+
 static ssize_t device_id_show(struct device *dev,
 			      struct device_attribute *attr,
 			      char *buf)
@@ -2929,6 +2978,26 @@ static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(guid);

+static ssize_t user_count_show(struct device *dev, struct device_attribute *attr,
+			       char *buf)
+{
+	unsigned int user_count = get_user_count();
+
+	return snprintf(buf, 20, "%u\n", user_count);
+}
+static DEVICE_ATTR_ADMIN_RO(user_count);
+
+static ssize_t msg_count_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	unsigned int hp_count, count;
+
+	get_msg_count(&hp_count, &count);
+
+	return snprintf(buf, 40, "hp msg:%u, msg:%u\n", hp_count, count);
+}
+static DEVICE_ATTR_ADMIN_RO(msg_count);
+
 static struct attribute *bmc_dev_attrs[] = {
 	&dev_attr_device_id.attr,
 	&dev_attr_provides_device_sdrs.attr,
@@ -2940,6 +3009,8 @@ static struct attribute *bmc_dev_attrs[] = {
 	&dev_attr_product_id.attr,
 	&dev_attr_aux_firmware_revision.attr,
 	&dev_attr_guid.attr,
+	&dev_attr_user_count.attr,
+	&dev_attr_msg_count.attr,
 	NULL
 };

--
2.25.1

[PATCH v2 4/4] ipmi: msghandler: Add a interface to clean message queue in sysfs

[Chen Guanqiao]

The further approach, add a cleanup interface in sysfs. The administrator write
'1' to clean_msg, and ipmi clear the entire message queue.

Signed-off-by: Chen Guanqiao <chen.chenchacha@foxmail.com>
---
 drivers/char/ipmi/ipmi_msghandler.c | 81 +++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index a188dc7e7135..58f3e17ee6b2 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -46,6 +46,9 @@ static void handle_new_recv_msgs(struct ipmi_smi *intf);
 static void need_waiter(struct ipmi_smi *intf);
 static int handle_one_recv_msg(struct ipmi_smi *intf,
 			       struct ipmi_smi_msg *msg);
+static void deliver_smi_err_response(struct ipmi_smi *intf,
+				     struct ipmi_smi_msg *msg,
+				     unsigned char err);

 static bool initialized;
 static bool drvregistered;
@@ -2809,6 +2812,70 @@ static void get_msg_count(unsigned int *hp_count, unsigned int *count)
 	srcu_read_unlock(&ipmi_interfaces_srcu, index);
 }

+static void __cleanup_msgs_queue(struct ipmi_smi *intf)
+{
+	int i;
+	unsigned long flags;
+	int run_to_completion = intf->run_to_completion;
+
+	rcu_read_lock();
+	if (!run_to_completion)
+		spin_lock_irqsave(&intf->xmit_msgs_lock, flags);
+	if (!intf->in_shutdown) {
+		struct ipmi_smi_msg *msg;
+		struct list_head *entry = NULL;
+
+		while (!list_empty(&intf->xmit_msgs)) {
+			if (!list_empty(&intf->hp_xmit_msgs))
+				entry = intf->hp_xmit_msgs.next;
+			else if (!list_empty(&intf->xmit_msgs))
+				entry = intf->xmit_msgs.next;
+
+			if (!entry)
+				continue;
+
+			list_del(entry);
+			msg = list_entry(entry, struct ipmi_smi_msg, link);
+			deliver_smi_err_response(intf, msg,
+						 IPMI_ERR_UNSPECIFIED);
+		}
+	}
+	if (!run_to_completion)
+		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
+	rcu_read_unlock();
+
+	spin_lock_irqsave(&intf->seq_lock, flags);
+	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
+		struct seq_table *ent = &intf->seq_table[i];
+		if (!ent->inuse)
+			continue;
+		deliver_err_response(intf, ent->recv_msg, IPMI_ERR_UNSPECIFIED);
+	}
+	spin_unlock_irqrestore(&intf->seq_lock, flags);
+}
+
+static void cleanup_msgs_queue(void)
+{
+	struct ipmi_smi *intf;
+	int index;
+
+	index = srcu_read_lock(&ipmi_interfaces_srcu);
+	list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
+		struct bmc_device *bmc = intf->bmc;
+
+		kref_get(&intf->refcount);
+		mutex_lock(&intf->bmc_reg_mutex);
+		mutex_lock(&bmc->dyn_mutex);
+
+		__cleanup_msgs_queue(intf);
+
+		mutex_unlock(&bmc->dyn_mutex);
+		mutex_unlock(&intf->bmc_reg_mutex);
+		kref_put(&intf->refcount, intf_free);
+	}
+	srcu_read_unlock(&ipmi_interfaces_srcu, index);
+}
+
 static ssize_t device_id_show(struct device *dev,
 			      struct device_attribute *attr,
 			      char *buf)
@@ -2998,6 +3065,19 @@ static ssize_t msg_count_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_ADMIN_RO(msg_count);

+static ssize_t clean_msgs_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	if (!sysfs_streq(buf, "1"))
+		return -EINVAL;
+
+	cleanup_msgs_queue();
+
+	return count;
+}
+static DEVICE_ATTR_WO(clean_msgs);
+
 static struct attribute *bmc_dev_attrs[] = {
 	&dev_attr_device_id.attr,
 	&dev_attr_provides_device_sdrs.attr,
@@ -3011,6 +3091,7 @@ static struct attribute *bmc_dev_attrs[] = {
 	&dev_attr_guid.attr,
 	&dev_attr_user_count.attr,
 	&dev_attr_msg_count.attr,
+	&dev_attr_clean_msgs.attr,
 	NULL
 };

--
2.25.1