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authorJohannes Berg <johannes.berg@intel.com>2013-11-19 15:19:33 +0100
committerDavid S. Miller <davem@davemloft.net>2013-11-19 16:39:05 -0500
commit2ecf7536b2787580616d23b6507005d930975ca0 (patch)
tree050b07aaf96d86a83ed42c34511a3f28e1c0d1d4 /net/netlink/genetlink.c
parente5dcecba015f9774a402ba559b80b16999747e3b (diff)
downloadlinux-2ecf7536b2787580616d23b6507005d930975ca0.tar.bz2
quota/genetlink: use proper genetlink multicast APIs
The quota code is abusing the genetlink API and is using its family ID as the multicast group ID, which is invalid and may belong to somebody else (and likely will.) Make the quota code use the correct API, but since this is already used as-is by userspace, reserve a family ID for this code and also reserve that group ID to not break userspace assumptions. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink/genetlink.c')
-rw-r--r--net/netlink/genetlink.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 353909d46dda..bee91a7527a5 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -69,8 +69,11 @@ static struct list_head family_ht[GENL_FAM_TAB_SIZE];
* abuses the API and thinks it can statically use group 1.
* That group will typically conflict with other groups that
* any proper users use.
+ * Bit 17 is marked as already used since the VFS quota code
+ * also abused this API and relied on family == group ID, we
+ * cater to that by giving it a static family and group ID.
*/
-static unsigned long mc_group_start = 0x3;
+static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_VFS_DQUOT);
static unsigned long *mc_groups = &mc_group_start;
static unsigned long mc_groups_longs = 1;
@@ -130,7 +133,8 @@ static u16 genl_generate_id(void)
int i;
for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
- if (!genl_family_find_byid(id_gen_idx))
+ if (id_gen_idx != GENL_ID_VFS_DQUOT &&
+ !genl_family_find_byid(id_gen_idx))
return id_gen_idx;
if (++id_gen_idx > GENL_MAX_ID)
id_gen_idx = GENL_MIN_ID;
@@ -169,6 +173,8 @@ int genl_register_mc_group(struct genl_family *family,
id = GENL_ID_CTRL;
else if (strcmp(family->name, "NET_DM") == 0)
id = 1;
+ else if (strcmp(family->name, "VFS_DQUOT") == 0)
+ id = GENL_ID_VFS_DQUOT;
else
id = find_first_zero_bit(mc_groups,
mc_groups_longs * BITS_PER_LONG);