1 files changed, 22 insertions, 15 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 01291b7a27bb..f19ec969edee 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -349,8 +349,6 @@ static int genl_validate_ops(const struct genl_family *family)
  *
  * Registers the specified family after validating it first. Only one
  * family may be registered with the same family name or identifier.
- * The family id may equal GENL_ID_GENERATE causing an unique id to
- * be automatically generated and assigned.
  *
  * The family's ops array must already be assigned, you can use the
  * genl_register_family_with_ops() helper function.
@@ -359,13 +357,7 @@ static int genl_validate_ops(const struct genl_family *family)
  */
 int __genl_register_family(struct genl_family *family)
 {
-        int err = -EINVAL, i;
-
-        if (family->id && family->id < GENL_MIN_ID)
-                goto errout;
-
-        if (family->id > GENL_MAX_ID)
-                goto errout;
+        int err, i;
 
         err = genl_validate_ops(family);
         if (err)
@@ -378,8 +370,27 @@ int __genl_register_family(struct genl_family *family)
                 goto errout_locked;
         }
 
-        if (family->id == GENL_ID_GENERATE) {
-                u16 newid = genl_generate_id();
+        if (family == &genl_ctrl) {
+                family->id = GENL_ID_CTRL;
+        } else {
+                u16 newid;
+
+                /* this should be left zero in the struct */
+                WARN_ON(family->id);
+
+                /*
+                 * Sadly, a few cases need to be special-cased
+                 * due to them having previously abused the API
+                 * and having used their family ID also as their
+                 * multicast group ID, so we use reserved IDs
+                 * for both to be sure we can do that mapping.
+                 */
+                if (strcmp(family->name, "pmcraid") == 0)
+                        newid = GENL_ID_PMCRAID;
+                else if (strcmp(family->name, "VFS_DQUOT") == 0)
+                        newid = GENL_ID_VFS_DQUOT;
+                else
+                        newid = genl_generate_id();
 
                 if (!newid) {
                         err = -ENOMEM;
@@ -387,9 +398,6 @@ int __genl_register_family(struct genl_family *family)
                 }
 
                 family->id = newid;
-        } else if (genl_family_find_byid(family->id)) {
-                err = -EEXIST;
-                goto errout_locked;
         }
 
         if (family->maxattr && !family->parallel_ops) {
@@ -419,7 +427,6 @@ int __genl_register_family(struct genl_family *family)
 
 errout_locked:
         genl_unlock_all();
-errout:
         return err;
 }
 EXPORT_SYMBOL(__genl_register_family);