[PATCH net-next 2/6] netconsole: implement configfs for release_enabled

[Breno Leitao]

Implement the configfs helpers to show and set release_enabled configfs
directories under userdata.

When enabled, set the feature bit in netconsole_target->sysdata_fields.

Signed-off-by: Breno Leitao <lei...@debian.org>
---
 drivers/net/netconsole.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index b7f7ec39e8318..0914d29b48d8e 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -442,6 +442,19 @@ static ssize_t sysdata_taskname_enabled_show(struct 
config_item *item,
        return sysfs_emit(buf, "%d\n", taskname_enabled);
 }
 
+static ssize_t sysdata_release_enabled_show(struct config_item *item,
+                                           char *buf)
+{
+       struct netconsole_target *nt = to_target(item->ci_parent);
+       bool release_enabled;
+
+       mutex_lock(&dynamic_netconsole_mutex);
+       release_enabled = !!(nt->sysdata_fields & SYSDATA_TASKNAME);
+       mutex_unlock(&dynamic_netconsole_mutex);
+
+       return sysfs_emit(buf, "%d\n", release_enabled);
+}
+
 /*
  * This one is special -- targets created through the configfs interface
  * are not enabled (and the corresponding netpoll activated) by default.
@@ -859,6 +872,40 @@ static void disable_sysdata_feature(struct 
netconsole_target *nt,
        nt->extradata_complete[nt->userdata_length] = 0;
 }
 
+static ssize_t sysdata_release_enabled_store(struct config_item *item,
+                                            const char *buf, size_t count)
+{
+       struct netconsole_target *nt = to_target(item->ci_parent);
+       bool release_enabled, curr;
+       ssize_t ret;
+
+       ret = kstrtobool(buf, &release_enabled);
+       if (ret)
+               return ret;
+
+       mutex_lock(&dynamic_netconsole_mutex);
+       curr = !!(nt->sysdata_fields & SYSDATA_RELEASE);
+       if (release_enabled == curr)
+               goto unlock_ok;
+
+       if (release_enabled &&
+           count_extradata_entries(nt) >= MAX_EXTRADATA_ITEMS) {
+               ret = -ENOSPC;
+               goto unlock;
+       }
+
+       if (release_enabled)
+               nt->sysdata_fields |= SYSDATA_RELEASE;
+       else
+               disable_sysdata_feature(nt, SYSDATA_RELEASE);
+
+unlock_ok:
+       ret = strnlen(buf, count);
+unlock:
+       mutex_unlock(&dynamic_netconsole_mutex);
+       return ret;
+}
+
 static ssize_t sysdata_taskname_enabled_store(struct config_item *item,
                                              const char *buf, size_t count)
 {
@@ -939,6 +986,7 @@ static ssize_t sysdata_cpu_nr_enabled_store(struct 
config_item *item,
 CONFIGFS_ATTR(userdatum_, value);
 CONFIGFS_ATTR(sysdata_, cpu_nr_enabled);
 CONFIGFS_ATTR(sysdata_, taskname_enabled);
+CONFIGFS_ATTR(sysdata_, release_enabled);
 
 static struct configfs_attribute *userdatum_attrs[] = {
        &userdatum_attr_value,
@@ -1000,6 +1048,7 @@ static void userdatum_drop(struct config_group *group, 
struct config_item *item)
 static struct configfs_attribute *userdata_attrs[] = {
        &sysdata_attr_cpu_nr_enabled,
        &sysdata_attr_taskname_enabled,
+       &sysdata_attr_release_enabled,
        NULL,
 };
 

-- 
2.47.1