MODULE_PARM_DESC(max_users,
"The most users that may use the IPMI stack at one time.");
+/* The default maximum number of message a user may have outstanding. */
+static unsigned int max_msgs_per_user = 100;
+module_param(max_msgs_per_user, uint, 0644);
+MODULE_PARM_DESC(max_msgs_per_user,
+ "The most message a user may have outstanding.");
+
/* Call every ~1000 ms. */
#define IPMI_TIMEOUT_TIME 1000
/* Does this interface receive IPMI events? */
bool gets_events;
+ atomic_t nr_msgs;
+
/* Free must run in process context for RCU cleanup. */
struct work_struct remove_work;
};
* risk. At this moment, simply skip it in that case.
*/
ipmi_free_recv_msg(msg);
+ atomic_dec(&msg->user->nr_msgs);
} else {
int index;
struct ipmi_user *user = acquire_ipmi_user(msg->user, &index);
if (user) {
+ atomic_dec(&user->nr_msgs);
user->handler->ipmi_recv_hndl(msg, user->handler_data);
release_ipmi_user(user, index);
} else {
/* Note that each existing user holds a refcount to the interface. */
kref_get(&intf->refcount);
+ atomic_set(&new_user->nr_msgs, 0);
kref_init(&new_user->refcount);
new_user->handler = handler;
new_user->handler_data = handler_data;
struct ipmi_recv_msg *recv_msg;
int rv = 0;
+ if (user) {
+ if (atomic_add_return(1, &user->nr_msgs) > max_msgs_per_user) {
+ /* Decrement will happen at the end of the routine. */
+ rv = -EBUSY;
+ goto out;
+ }
+ }
+
if (supplied_recv)
recv_msg = supplied_recv;
else {
rcu_read_unlock();
out:
+ if (rv && user)
+ atomic_dec(&user->nr_msgs);
return rv;
}