diff mbox series

[v2,net-next,10/14] inet: allow ip_valid_fib_dump_req() to be called with RTNL or RCU

Message ID 20240222105021.1943116-11-edumazet@google.com (mailing list archive)
State Accepted
Commit 22e36ea9f5d7707ae3d64c497d172f4ef735c353
Delegated to: Netdev Maintainers
Headers show
Series rtnetlink: reduce RTNL pressure for dumps | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 2770 this patch: 2770
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 2 maintainers not CCed: joel.granados@gmail.com dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 997 this patch: 997
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 2983 this patch: 2983
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-02-23--03-00 (tests: 1457)

Commit Message

Eric Dumazet Feb. 22, 2024, 10:50 a.m. UTC 
Add a new field into struct fib_dump_filter, to let callers
tell if they use RTNL locking or RCU.

This is used in the following patch, when inet_dump_fib()
no longer holds RTNL.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/ip_fib.h    |  1 +
 net/ipv4/fib_frontend.c | 15 +++++++++++----
 net/ipv4/ipmr.c         |  4 +++-
 net/ipv6/ip6_fib.c      |  7 +++++--
 net/ipv6/ip6mr.c        |  4 +++-
 net/mpls/af_mpls.c      |  4 +++-
 6 files changed, 26 insertions(+), 9 deletions(-)

Comments

Donald Hunter Feb. 23, 2024, 3:22 p.m. UTC | #1 
Eric Dumazet <edumazet@google.com> writes:

> Add a new field into struct fib_dump_filter, to let callers
> tell if they use RTNL locking or RCU.
>
> This is used in the following patch, when inet_dump_fib()
> no longer holds RTNL.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
diff mbox series

Patch

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index d4667b7797e3e4591f3ff1fe641f168295e0a894..9b2f69ba5e4981fb108581c229ff008d04750ade 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -264,6 +264,7 @@  struct fib_dump_filter {
 	bool			filter_set;
 	bool			dump_routes;
 	bool			dump_exceptions;
+	bool			rtnl_held;
 	unsigned char		protocol;
 	unsigned char		rt_type;
 	unsigned int		flags;
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 390f4be7f7bec20f33aa80e9bf12d5e2f3760562..39f67990e01c19b73a622dced0220a1bba21d5e6 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -916,7 +916,8 @@  int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
 	struct rtmsg *rtm;
 	int err, i;
 
-	ASSERT_RTNL();
+	if (filter->rtnl_held)
+		ASSERT_RTNL();
 
 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
 		NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
@@ -961,7 +962,10 @@  int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
 			break;
 		case RTA_OIF:
 			ifindex = nla_get_u32(tb[i]);
-			filter->dev = __dev_get_by_index(net, ifindex);
+			if (filter->rtnl_held)
+				filter->dev = __dev_get_by_index(net, ifindex);
+			else
+				filter->dev = dev_get_by_index_rcu(net, ifindex);
 			if (!filter->dev)
 				return -ENODEV;
 			break;
@@ -983,8 +987,11 @@  EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
 
 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	struct fib_dump_filter filter = { .dump_routes = true,
-					  .dump_exceptions = true };
+	struct fib_dump_filter filter = {
+		.dump_routes = true,
+		.dump_exceptions = true,
+		.rtnl_held = true,
+	};
 	const struct nlmsghdr *nlh = cb->nlh;
 	struct net *net = sock_net(skb->sk);
 	unsigned int h, s_h;
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 5561bce3a37e8f72d08ff8062d6b8cde08bbed44..0708ac6f6c582681ab1f2b52c5ce1f2a4acd10de 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -2587,7 +2587,9 @@  static int ipmr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 
 static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	struct fib_dump_filter filter = {};
+	struct fib_dump_filter filter = {
+		.rtnl_held = true,
+	};
 	int err;
 
 	if (cb->strict_check) {
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 6540d877d3693e788d000309950f3735554c937d..5c558dc1c6838681c2848412dced72a41fe764be 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -620,8 +620,11 @@  static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 
 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	struct rt6_rtnl_dump_arg arg = { .filter.dump_exceptions = true,
-					 .filter.dump_routes = true };
+	struct rt6_rtnl_dump_arg arg = {
+		.filter.dump_exceptions = true,
+		.filter.dump_routes = true,
+		.filter.rtnl_held = true,
+	};
 	const struct nlmsghdr *nlh = cb->nlh;
 	struct net *net = sock_net(skb->sk);
 	unsigned int h, s_h;
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 1f19743f254064852139809143b60c1d397fe1d8..cb0ee81a068a4c895d5d8b21f3fc557bf1784dfb 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2592,7 +2592,9 @@  static int ip6mr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 static int ip6mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	const struct nlmsghdr *nlh = cb->nlh;
-	struct fib_dump_filter filter = {};
+	struct fib_dump_filter filter = {
+		.rtnl_held = true,
+	};
 	int err;
 
 	if (cb->strict_check) {
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 1af29af65388584e9666f4fcb73a16e8ff159587..6dab883a08dda46ff6ddc1e6e407e6f48a10c8aa 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -2179,7 +2179,9 @@  static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
 	const struct nlmsghdr *nlh = cb->nlh;
 	struct net *net = sock_net(skb->sk);
 	struct mpls_route __rcu **platform_label;
-	struct fib_dump_filter filter = {};
+	struct fib_dump_filter filter = {
+		.rtnl_held = true,
+	};
 	unsigned int flags = NLM_F_MULTI;
 	size_t platform_labels;
 	unsigned int index;