From 3b0f31f2b8c9fb348e4530b88f6b64f9621f83d6 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 21 Mar 2019 22:51:02 +0100 Subject: genetlink: make policy common to family Since maxattr is common, the policy can't really differ sanely, so make it common as well. The only user that did in fact manage to make a non-common policy is taskstats, which has to be really careful about it (since it's still using a common maxattr!). This is no longer supported, but we can fake it using pre_doit. This reduces the size of e.g. nl80211.o (which has lots of commands): text data bss dec hex filename 398745 14323 2240 415308 6564c net/wireless/nl80211.o (before) 397913 14331 2240 414484 65314 net/wireless/nl80211.o (after) -------------------------------- -832 +8 0 -824 Which is obviously just 8 bytes for each command, and an added 8 bytes for the new policy pointer. I'm not sure why the ops list is counted as .text though. Most of the code transformations were done using the following spatch: @ops@ identifier OPS; expression POLICY; @@ struct genl_ops OPS[] = { ..., { - .policy = POLICY, }, ... }; @@ identifier ops.OPS; expression ops.POLICY; identifier fam; expression M; @@ struct genl_family fam = { .ops = OPS, .maxattr = M, + .policy = POLICY, ... }; This also gets rid of devlink_nl_cmd_region_read_dumpit() accessing the cb->data as ops, which we want to change in a later genl patch. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- kernel/taskstats.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/taskstats.c b/kernel/taskstats.c index 4e62a4a8fa91..1b942a7caf26 100644 --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -650,16 +650,37 @@ static const struct genl_ops taskstats_ops[] = { { .cmd = TASKSTATS_CMD_GET, .doit = taskstats_user_cmd, - .policy = taskstats_cmd_get_policy, - .flags = GENL_ADMIN_PERM, + /* policy enforced later */ + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_HASPOL, }, { .cmd = CGROUPSTATS_CMD_GET, .doit = cgroupstats_user_cmd, - .policy = cgroupstats_cmd_get_policy, + /* policy enforced later */ + .flags = GENL_CMD_CAP_HASPOL, }, }; +static int taskstats_pre_doit(const struct genl_ops *ops, struct sk_buff *skb, + struct genl_info *info) +{ + const struct nla_policy *policy = NULL; + + switch (ops->cmd) { + case TASKSTATS_CMD_GET: + policy = taskstats_cmd_get_policy; + break; + case CGROUPSTATS_CMD_GET: + policy = cgroupstats_cmd_get_policy; + break; + default: + return -EINVAL; + } + + return nlmsg_validate(info->nlhdr, GENL_HDRLEN, TASKSTATS_CMD_ATTR_MAX, + policy, info->extack); +} + static struct genl_family family __ro_after_init = { .name = TASKSTATS_GENL_NAME, .version = TASKSTATS_GENL_VERSION, @@ -667,6 +688,7 @@ static struct genl_family family __ro_after_init = { .module = THIS_MODULE, .ops = taskstats_ops, .n_ops = ARRAY_SIZE(taskstats_ops), + .pre_doit = taskstats_pre_doit, }; /* Needed early in initialization */ -- cgit v1.2.3