netconsole: Helper to count number of used entries

Add a helper function nr_extradata_entries() to count the number of used
extradata entries in a netconsole target. This refactors the duplicate
code for counting entries into a single function, which will be reused
by upcoming CPU sysdata changes.

The helper uses list_count_nodes() to count the number of children in
the userdata group configfs hierarchy.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 7f05c7f74c31ce26a7329c784bd99305b7bea0e8..15daaba65c8827bf399f0623cc42d310626cbf68 100644 (file)
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -662,6 +662,16 @@ out_unlock:
        return ret;
 }
 
+/* Count number of entries we have in extradata.
+ * This is important because the extradata_complete only supports
+ * MAX_EXTRADATA_ITEMS entries. Before enabling any new {user,sys}data
+ * feature, number of entries needs to checked for available space.
+ */
+static size_t count_extradata_entries(struct netconsole_target *nt)
+{
+       return list_count_nodes(&nt->userdata_group.cg_children);
+}
+
 static ssize_t remote_mac_store(struct config_item *item, const char *buf,
                size_t count)
 {
@@ -811,15 +821,13 @@ static struct config_item *userdatum_make_item(struct config_group *group,
        struct netconsole_target *nt;
        struct userdatum *udm;
        struct userdata *ud;
-       size_t child_count;
 
        if (strlen(name) > MAX_EXTRADATA_NAME_LEN)
                return ERR_PTR(-ENAMETOOLONG);
 
        ud = to_userdata(&group->cg_item);
        nt = userdata_to_target(ud);
-       child_count = list_count_nodes(&nt->userdata_group.cg_children);
-       if (child_count >= MAX_EXTRADATA_ITEMS)
+       if (count_extradata_entries(nt) >= MAX_EXTRADATA_ITEMS)
                return ERR_PTR(-ENOSPC);
 
        udm = kzalloc(sizeof(*udm), GFP_KERNEL);