netconsole: implement configfs for msgid_enabled

Implement the _show and _store functions for the msgid_enabled configfs
attribute under userdata.
Set the sysdata_fields bit accordingly.

Reviewed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Gustavo Luiz Duarte <gustavold@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 2a273b29e276e5c8a8e2d2550ecdd3780ff82d21..5e66a568954f17642a8959d8bac75b7e814ea260 100644 (file)
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -506,6 +506,19 @@ static void unregister_netcons_consoles(void)
                unregister_console(&netconsole);
 }
 
+static ssize_t sysdata_msgid_enabled_show(struct config_item *item,
+                                         char *buf)
+{
+       struct netconsole_target *nt = to_target(item->ci_parent);
+       bool msgid_enabled;
+
+       mutex_lock(&dynamic_netconsole_mutex);
+       msgid_enabled = !!(nt->sysdata_fields & SYSDATA_MSGID);
+       mutex_unlock(&dynamic_netconsole_mutex);
+
+       return sysfs_emit(buf, "%d\n", msgid_enabled);
+}
+
 /*
  * This one is special -- targets created through the configfs interface
  * are not enabled (and the corresponding netpoll activated) by default.
@@ -939,6 +952,40 @@ static void disable_sysdata_feature(struct netconsole_target *nt,
        nt->extradata_complete[nt->userdata_length] = 0;
 }
 
+static ssize_t sysdata_msgid_enabled_store(struct config_item *item,
+                                          const char *buf, size_t count)
+{
+       struct netconsole_target *nt = to_target(item->ci_parent);
+       bool msgid_enabled, curr;
+       ssize_t ret;
+
+       ret = kstrtobool(buf, &msgid_enabled);
+       if (ret)
+               return ret;
+
+       mutex_lock(&dynamic_netconsole_mutex);
+       curr = !!(nt->sysdata_fields & SYSDATA_MSGID);
+       if (msgid_enabled == curr)
+               goto unlock_ok;
+
+       if (msgid_enabled &&
+           count_extradata_entries(nt) >= MAX_EXTRADATA_ITEMS) {
+               ret = -ENOSPC;
+               goto unlock;
+       }
+
+       if (msgid_enabled)
+               nt->sysdata_fields |= SYSDATA_MSGID;
+       else
+               disable_sysdata_feature(nt, SYSDATA_MSGID);
+
+unlock_ok:
+       ret = strnlen(buf, count);
+unlock:
+       mutex_unlock(&dynamic_netconsole_mutex);
+       return ret;
+}
+
 static ssize_t sysdata_release_enabled_store(struct config_item *item,
                                             const char *buf, size_t count)
 {
@@ -1054,6 +1101,7 @@ CONFIGFS_ATTR(userdatum_, value);
 CONFIGFS_ATTR(sysdata_, cpu_nr_enabled);
 CONFIGFS_ATTR(sysdata_, taskname_enabled);
 CONFIGFS_ATTR(sysdata_, release_enabled);
+CONFIGFS_ATTR(sysdata_, msgid_enabled);
 
 static struct configfs_attribute *userdatum_attrs[] = {
        &userdatum_attr_value,
@@ -1116,6 +1164,7 @@ static struct configfs_attribute *userdata_attrs[] = {
        &sysdata_attr_cpu_nr_enabled,
        &sysdata_attr_taskname_enabled,
        &sysdata_attr_release_enabled,
+       &sysdata_attr_msgid_enabled,
        NULL,
 };