diff mbox series

[v2,net-next,6/7] neighbour: Convert RTM_GETNEIGHTBL to RCU.

Message ID 20250418012727.57033-7-kuniyu@amazon.com (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series neighbour: Convert RTM_GETNEIGH and RTM_{GET,SET}NEIGHTBL to RCU. | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
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: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: gnaaman@drivenets.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
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: 2 this patch: 2
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 30 lines checked
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-2025-04-18--12-00 (tests: 916)

Commit Message

Kuniyuki Iwashima April 18, 2025, 1:26 a.m. UTC 
neightbl_dump_info() calls neightbl_fill_info() and
neightbl_fill_param_info() for each neigh_tables[] entry.

Both functions rely on the table lock (read_lock_bh(&tbl->lock)),
so RTNL is not needed.

Let's fetch the table under RCU and convert RTM_GETNEIGHTBL to RCU.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/core/neighbour.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index ccfef86bb044..38732d8f0ed7 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2467,10 +2467,12 @@  static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 
 	family = ((struct rtgenmsg *)nlmsg_data(nlh))->rtgen_family;
 
+	rcu_read_lock();
+
 	for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
 		struct neigh_parms *p;
 
-		tbl = rcu_dereference_rtnl(neigh_tables[tidx]);
+		tbl = rcu_dereference(neigh_tables[tidx]);
 		if (!tbl)
 			continue;
 
@@ -2504,6 +2506,8 @@  static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 		neigh_skip = 0;
 	}
 out:
+	rcu_read_unlock();
+
 	cb->args[0] = tidx;
 	cb->args[1] = nidx;
 
@@ -3811,7 +3815,8 @@  static const struct rtnl_msg_handler neigh_rtnl_msg_handlers[] __initconst = {
 	{.msgtype = RTM_DELNEIGH, .doit = neigh_delete},
 	{.msgtype = RTM_GETNEIGH, .doit = neigh_get, .dumpit = neigh_dump_info,
 	 .flags = RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},
-	{.msgtype = RTM_GETNEIGHTBL, .dumpit = neightbl_dump_info},
+	{.msgtype = RTM_GETNEIGHTBL, .dumpit = neightbl_dump_info,
+	 .flags = RTNL_FLAG_DUMP_UNLOCKED},
 	{.msgtype = RTM_SETNEIGHTBL, .doit = neightbl_set},
 };