ipmi: Add a sysfs count of total outstanding messages for an interface

Go through each user and add its message count to a total and print the
total.

It would be nice to have a per-user file, but there's no user sysfs
entity at this point to hang it off of.  Probably not worth the effort.

Based on work by Chen Guanqiao <chen.chenchacha@foxmail.com>

Cc: Chen Guanqiao <chen.chenchacha@foxmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 8b5d397..5d033fa 100644 (file)
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -458,6 +458,7 @@ struct ipmi_smi {
        struct srcu_struct users_srcu;
        atomic_t nr_users;
        struct device_attribute nr_users_devattr;
+       struct device_attribute nr_msgs_devattr;
 
 
        /* Used for wake ups at startup. */
@@ -3519,6 +3520,25 @@ static ssize_t nr_users_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(nr_users);
 
+static ssize_t nr_msgs_show(struct device *dev,
+                           struct device_attribute *attr,
+                           char *buf)
+{
+       struct ipmi_smi *intf = container_of(attr,
+                        struct ipmi_smi, nr_msgs_devattr);
+       struct ipmi_user *user;
+       int index;
+       unsigned int count = 0;
+
+       index = srcu_read_lock(&intf->users_srcu);
+       list_for_each_entry_rcu(user, &intf->users, link)
+               count += atomic_read(&user->nr_msgs);
+       srcu_read_unlock(&intf->users_srcu, index);
+
+       return sysfs_emit(buf, "%u\n", count);
+}
+static DEVICE_ATTR_RO(nr_msgs);
+
 static void redo_bmc_reg(struct work_struct *work)
 {
        struct ipmi_smi *intf = container_of(work, struct ipmi_smi,
@@ -3647,6 +3667,14 @@ int ipmi_add_smi(struct module         *owner,
        if (rv)
                goto out_err_bmc_reg;
 
+       intf->nr_msgs_devattr = dev_attr_nr_msgs;
+       sysfs_attr_init(&intf->nr_msgs_devattr.attr);
+       rv = device_create_file(intf->si_dev, &intf->nr_msgs_devattr);
+       if (rv) {
+               device_remove_file(intf->si_dev, &intf->nr_users_devattr);
+               goto out_err_bmc_reg;
+       }
+
        /*
         * Keep memory order straight for RCU readers.  Make
         * sure everything else is committed to memory before
@@ -3746,6 +3774,7 @@ void ipmi_unregister_smi(struct ipmi_smi *intf)
 
        /* At this point no users can be added to the interface. */
 
+       device_remove_file(intf->si_dev, &intf->nr_msgs_devattr);
        device_remove_file(intf->si_dev, &intf->nr_users_devattr);
 
        /*