diff mbox series

[net-next,1/8] rtnetlink: do not depend on RTNL for IFLA_QDISC output

Message ID 20240503192059.3884225-2-edumazet@google.com (mailing list archive)
State Accepted
Commit 698419ffb6fc83dd7b0359d9e8476e732967eed2
Delegated to: Netdev Maintainers
Headers show
Series rtnetlink: more rcu conversions for rtnl_fill_ifinfo() | 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: 928 this patch: 928
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/build_clang success Errors and warnings before: 938 this patch: 938
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: 939 this patch: 939
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 24 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 6 this patch: 6
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-05-05--03-00 (tests: 1003)

Commit Message

Eric Dumazet May 3, 2024, 7:20 p.m. UTC 
dev->qdisc can be read using RCU protection.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/core/rtnetlink.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Simon Horman May 5, 2024, 2:48 p.m. UTC | #1 
On Fri, May 03, 2024 at 07:20:52PM +0000, Eric Dumazet wrote:
> dev->qdisc can be read using RCU protection.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Reviewed-by: Simon Horman <horms@kernel.org>
diff mbox series

Patch

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 283e42f48af68504af193ed5763d4e0fcd667d99..f4a87f89d5cde0cdd35c156d78ebe31511d4a31c 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1832,7 +1832,6 @@  static int rtnl_fill_ifinfo(struct sk_buff *skb,
 	if (tgt_netnsid >= 0 && nla_put_s32(skb, IFLA_TARGET_NETNSID, tgt_netnsid))
 		goto nla_put_failure;
 
-	qdisc = rtnl_dereference(dev->qdisc);
 	if (nla_put_string(skb, IFLA_IFNAME, dev->name) ||
 	    nla_put_u32(skb, IFLA_TXQLEN, dev->tx_queue_len) ||
 	    nla_put_u8(skb, IFLA_OPERSTATE,
@@ -1857,8 +1856,6 @@  static int rtnl_fill_ifinfo(struct sk_buff *skb,
 #endif
 	    put_master_ifindex(skb, dev) ||
 	    nla_put_u8(skb, IFLA_CARRIER, netif_carrier_ok(dev)) ||
-	    (qdisc &&
-	     nla_put_string(skb, IFLA_QDISC, qdisc->ops->id)) ||
 	    nla_put_ifalias(skb, dev) ||
 	    nla_put_u32(skb, IFLA_CARRIER_CHANGES,
 			atomic_read(&dev->carrier_up_count) +
@@ -1924,6 +1921,9 @@  static int rtnl_fill_ifinfo(struct sk_buff *skb,
 		goto nla_put_failure;
 
 	rcu_read_lock();
+	qdisc = rcu_dereference(dev->qdisc);
+	if (qdisc && nla_put_string(skb, IFLA_QDISC, qdisc->ops->id))
+		goto nla_put_failure_rcu;
 	if (rtnl_fill_link_af(skb, dev, ext_filter_mask))
 		goto nla_put_failure_rcu;
 	if (rtnl_fill_link_ifmap(skb, dev))