On Fri, 2007-06-29 at 15:53 +0200, Patrick McHardy wrote:

> If you're worried about patch size, you could sell that part as a
> bugfix :)

Heh. Actually, right now I'm more worried about how much work I have to
do short-term.

This patch keeps the bitmap but does dynamic group allocation. Just to
see where I'm right now, I have a few things I'd like to change like not
sending out the full family info if it registers a new group.


---
 include/linux/genetlink.h |   13 ++++++
 include/net/genetlink.h   |   18 +++++++++
 net/netlink/genetlink.c   |   89 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 120 insertions(+)

--- wireless-dev.orig/include/net/genetlink.h   2007-06-26 16:58:42.154806179 
+0200
+++ wireless-dev/include/net/genetlink.h        2007-06-29 15:40:35.547910932 
+0200
@@ -5,6 +5,20 @@
 #include <net/netlink.h>
 
 /**
+ * struct genl_multicast_group - generic netlink multicast group
+ * @name: name of the multicast group, names are per-family
+ * @id: multicast group ID, assigned by the core, to use with
+ *      genlmsg_multicast().
+ * @list: list entry for linking
+ */
+struct genl_multicast_group
+{
+       struct list_head        list;           /* private */
+       char                    name[GENL_NAMSIZ];
+       u32                     id;
+};
+
+/**
  * struct genl_family - generic netlink family
  * @id: protocol family idenfitier
  * @hdrsize: length of user specific header in bytes
@@ -14,6 +28,7 @@
  * @attrbuf: buffer to store parsed attributes
  * @ops_list: list of all assigned operations
  * @family_list: family list
+ * @mcast_groups: multicast groups list
  */
 struct genl_family
 {
@@ -25,6 +40,7 @@ struct genl_family
        struct nlattr **        attrbuf;        /* private */
        struct list_head        ops_list;       /* private */
        struct list_head        family_list;    /* private */
+       struct list_head        mcast_groups;   /* private */
 };
 
 /**
@@ -73,6 +89,8 @@ extern int genl_register_family(struct g
 extern int genl_unregister_family(struct genl_family *family);
 extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
 extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);
+extern int genl_register_mc_group(struct genl_family *family,
+                                 struct genl_multicast_group *grp);
 
 extern struct sock *genl_sock;
 
--- wireless-dev.orig/net/netlink/genetlink.c   2007-06-26 16:58:42.244806179 
+0200
+++ wireless-dev/net/netlink/genetlink.c        2007-06-29 16:01:38.487910932 
+0200
@@ -3,6 +3,7 @@
  *
  *             Authors:        Jamal Hadi Salim
  *                             Thomas Graf <[EMAIL PROTECTED]>
+ *                             Johannes Berg <[EMAIL PROTECTED]>
  */
 
 #include <linux/module.h>
@@ -13,6 +14,7 @@
 #include <linux/string.h>
 #include <linux/skbuff.h>
 #include <linux/mutex.h>
+#include <linux/bitmap.h>
 #include <net/sock.h>
 #include <net/genetlink.h>
 
@@ -42,6 +44,16 @@ static void genl_unlock(void)
 #define GENL_FAM_TAB_MASK      (GENL_FAM_TAB_SIZE - 1)
 
 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
+/*
+ * Bitmap of multicast groups that are currently in use.
+ *
+ * To avoid an allocation at boot of just one unsigned long,
+ * declare it global instead.
+ * Bit 1 is marked as already used since group 1 is the controller group.
+ */
+static unsigned long mc_group_start = 0x2;
+static unsigned long *mc_groups = &mc_group_start;
+static unsigned long mc_groups_bits = BITS_PER_LONG;
 
 static int genl_ctrl_event(int event, void *data);
 
@@ -116,6 +128,55 @@ static inline u16 genl_generate_id(void)
        return id_gen_idx;
 }
 
+int genl_register_mc_group(struct genl_family *family,
+                          struct genl_multicast_group *grp)
+{
+       int id = find_first_zero_bit(mc_groups, mc_groups_bits);
+
+       if (id >= mc_groups_bits) {
+               if (mc_groups == &mc_group_start) {
+                       mc_groups =
+                               kzalloc(mc_groups_bits/BITS_PER_LONG + 1,
+                                       GFP_KERNEL);
+                       if (!mc_groups)
+                               return -ENOMEM;
+                       *mc_groups = mc_group_start;
+               } else {
+                       mc_groups =
+                               krealloc(mc_groups,
+                                        mc_groups_bits/BITS_PER_LONG + 1,
+                                        GFP_KERNEL);
+                       if (!mc_groups)
+                               return -ENOMEM;
+                       mc_groups[mc_groups_bits/BITS_PER_LONG] = 0;
+               }
+               mc_groups_bits += BITS_PER_LONG;
+       }
+
+       grp->id = id;
+       set_bit(id, mc_groups);
+       list_add_tail(&grp->list, &family->mcast_groups);
+
+       genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family);
+
+       return 0;
+}
+EXPORT_SYMBOL(genl_register_mc_group);
+
+static void genl_unregister_mcast_group(struct genl_multicast_group *grp)
+{
+       clear_bit(grp->id, mc_groups);
+       list_del(&grp->list);
+}
+
+static void genl_unregister_mcast_groups(struct genl_family *family)
+{
+       struct genl_multicast_group *grp, *tmp;
+
+       list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
+               genl_unregister_mcast_group(grp);
+}
+
 /**
  * genl_register_ops - register generic netlink operations
  * @family: generic netlink family
@@ -290,6 +351,8 @@ int genl_unregister_family(struct genl_f
                return 0;
        }
 
+       genl_unregister_mcast_groups(family);
+
        genl_unlock();
 
        return -ENOENT;
@@ -410,6 +473,31 @@ static int ctrl_fill_info(struct genl_fa
                nla_nest_end(skb, nla_ops);
        }
 
+       if (!list_empty(&family->mcast_groups)) {
+               struct genl_multicast_group *grp;
+               struct nlattr *nla_grps;
+               int idx = 1;
+
+               nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+               if (nla_grps == NULL)
+                       goto nla_put_failure;
+
+               list_for_each_entry(grp, &family->mcast_groups, list) {
+                       struct nlattr *nest;
+
+                       nest = nla_nest_start(skb, idx++);
+                       if (nest == NULL)
+                               goto nla_put_failure;
+
+                       NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
+                       NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
+                                      grp->name);
+
+                       nla_nest_end(skb, nest);
+               }
+               nla_nest_end(skb, nla_grps);
+       }
+
        return genlmsg_end(skb, hdr);
 
 nla_put_failure:
@@ -523,6 +611,7 @@ static int genl_ctrl_event(int event, vo
        switch (event) {
        case CTRL_CMD_NEWFAMILY:
        case CTRL_CMD_DELFAMILY:
+       case CTRL_CMD_NEWMCAST_GRP:
                msg = ctrl_build_msg(data, 0, 0, event);
                if (IS_ERR(msg))
                        return PTR_ERR(msg);
--- wireless-dev.orig/include/linux/genetlink.h 2007-06-26 16:58:42.174806179 
+0200
+++ wireless-dev/include/linux/genetlink.h      2007-06-29 16:00:05.687910932 
+0200
@@ -39,6 +39,9 @@ enum {
        CTRL_CMD_NEWOPS,
        CTRL_CMD_DELOPS,
        CTRL_CMD_GETOPS,
+       CTRL_CMD_NEWMCAST_GRP,
+       CTRL_CMD_DELMCAST_GRP, /* unused */
+       CTRL_CMD_GETMCAST_GRP, /* unused */
        __CTRL_CMD_MAX,
 };
 
@@ -52,6 +55,7 @@ enum {
        CTRL_ATTR_HDRSIZE,
        CTRL_ATTR_MAXATTR,
        CTRL_ATTR_OPS,
+       CTRL_ATTR_MCAST_GROUPS,
        __CTRL_ATTR_MAX,
 };
 
@@ -66,4 +70,13 @@ enum {
 
 #define CTRL_ATTR_OP_MAX (__CTRL_ATTR_OP_MAX - 1)
 
+enum {
+       CTRL_ATTR_MCAST_GRP_UNSPEC,
+       CTRL_ATTR_MCAST_GRP_NAME,
+       CTRL_ATTR_MCAST_GRP_ID,
+       __CTRL_ATTR_MCAST_GRP_MAX,
+};
+
+#define CTRL_ATTR_MCAST_GRP_MAX (__CTRL_ATTR_MCAST_GRP_MAX - 1)
+
 #endif /* __LINUX_GENERIC_NETLINK_H */


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