From 2c7bc10d0f7b0f66d9042ed88bb3ecd588352a00 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 4 Jan 2023 20:05:21 -0800 Subject: [PATCH] netlink: add macro for checking dump ctx size We encourage casting struct netlink_callback::ctx to a local struct (in a comment above the field). Provide a convenience macro for checking if the local struct fits into the ctx. Reviewed-by: Jacob Keller Reviewed-by: Jiri Pirko Signed-off-by: Jakub Kicinski --- include/linux/netlink.h | 4 ++++ net/netfilter/nf_conntrack_netlink.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/include/linux/netlink.h b/include/linux/netlink.h index d81bde5a5844..38f6334f408c 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -263,6 +263,10 @@ struct netlink_callback { }; }; +#define NL_ASSET_DUMP_CTX_FITS(type_name) \ + BUILD_BUG_ON(sizeof(type_name) > \ + sizeof_field(struct netlink_callback, ctx)) + struct netlink_notify { struct net *net; u32 portid; diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 1286ae7d4609..90672e293e57 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -3866,7 +3866,7 @@ static int __init ctnetlink_init(void) { int ret; - BUILD_BUG_ON(sizeof(struct ctnetlink_list_dump_ctx) > sizeof_field(struct netlink_callback, ctx)); + NL_ASSET_DUMP_CTX_FITS(struct ctnetlink_list_dump_ctx); ret = nfnetlink_subsys_register(&ctnl_subsys); if (ret < 0) {