From a6fbbaa64c3b0e744e7e421a13658a7441f5a9f3 Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Thu, 28 Jan 2021 13:49:21 +0100 Subject: nexthop: Strongly-type context of rtm_dump_nexthop() The dump operations need to keep state from one invocation to another. A scratch area is dedicated for this purpose in the passed-in argument, cb, namely via two aliased arrays, struct netlink_callback.args and .ctx. Dumping of buckets will end up having to iterate over next hops as well, and it would be nice to be able to reuse the iteration logic with the NH dumper. The fact that the logic currently relies on fixed index to the .args array, and the indices would have to be coordinated between the two dumpers, makes this somewhat awkward. To make the access patters clearer, introduce a helper struct with a NH index, and instead of using the .args array directly, use it through this structure. Signed-off-by: Petr Machata Reviewed-by: Ido Schimmel Reviewed-by: David Ahern Signed-off-by: Jakub Kicinski --- net/ipv4/nexthop.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'net/ipv4/nexthop.c') diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c index 1c4f10fe3b4e..7ae197efa5a9 100644 --- a/net/ipv4/nexthop.c +++ b/net/ipv4/nexthop.c @@ -2066,9 +2066,23 @@ static int nh_valid_dump_req(const struct nlmsghdr *nlh, return __nh_valid_dump_req(nlh, tb, filter, cb->extack); } +struct rtm_dump_nh_ctx { + u32 idx; +}; + +static struct rtm_dump_nh_ctx * +rtm_dump_nh_ctx(struct netlink_callback *cb) +{ + struct rtm_dump_nh_ctx *ctx = (void *)cb->ctx; + + BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx)); + return ctx; +} + /* rtnl */ static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb) { + struct rtm_dump_nh_ctx *ctx = rtm_dump_nh_ctx(cb); struct nhmsg *nhm = nlmsg_data(cb->nlh); struct net *net = sock_net(skb->sk); struct rb_root *root = &net->nexthop.rb_root; @@ -2081,7 +2095,7 @@ static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb) if (err < 0) return err; - s_idx = cb->args[0]; + s_idx = ctx->idx; for (node = rb_first(root); node; node = rb_next(node)) { struct nexthop *nh; @@ -2108,7 +2122,7 @@ cont: out: err = skb->len; out_err: - cb->args[0] = idx; + ctx->idx = idx; cb->seq = net->nexthop.seq; nl_dump_check_consistent(cb, nlmsg_hdr(skb)); -- cgit v1.2.3