From: Kuniyuki Iwashima Date: Mon, 21 Oct 2024 18:32:28 +0000 (-0700) Subject: rtnetlink: Make per-netns RTNL dereference helpers to macro. X-Git-Tag: v6.13-rc1~135^2~216^2~11 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9cb7e40d388d6c0e4677809c6b2950bc67fd8830;p=thirdparty%2Fkernel%2Flinux.git rtnetlink: Make per-netns RTNL dereference helpers to macro. When CONFIG_DEBUG_NET_SMALL_RTNL is off, rtnl_net_dereference() is the static inline wrapper of rtnl_dereference() returning a plain (void *) pointer to make sure net is always evaluated as requested in [0]. But, it makes sparse complain [1] when the pointer has __rcu annotation: net/ipv4/devinet.c:674:47: sparse: warning: incorrect type in argument 2 (different address spaces) net/ipv4/devinet.c:674:47: sparse: expected void *p net/ipv4/devinet.c:674:47: sparse: got struct in_ifaddr [noderef] __rcu * Also, if we evaluate net as (void *) in a macro, then the compiler in turn fails to build due to -Werror=unused-value. #define rtnl_net_dereference(net, p) \ ({ \ (void *)net; \ rtnl_dereference(p); \ }) net/ipv4/devinet.c: In function ‘inet_rtm_deladdr’: ./include/linux/rtnetlink.h:154:17: error: statement with no effect [-Werror=unused-value] 154 | (void *)net; \ net/ipv4/devinet.c:674:21: note: in expansion of macro ‘rtnl_net_dereference’ 674 | (ifa = rtnl_net_dereference(net, *ifap)) != NULL; | ^~~~~~~~~~~~~~~~~~~~ Let's go back to the original simplest macro. Note that checkpatch complains about this approach, but it's one-shot and less noisy than the other two. WARNING: Argument 'net' is not used in function-like macro #76: FILE: include/linux/rtnetlink.h:142: +#define rtnl_net_dereference(net, p) \ + rtnl_dereference(p) Fixes: 844e5e7e656d ("rtnetlink: Add assertion helpers for per-netns RTNL.") Link: https://lore.kernel.org/netdev/20241004132145.7fd208e9@kernel.org/ [0] Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202410200325.SaEJmyZS-lkp@intel.com/ [1] Signed-off-by: Kuniyuki Iwashima Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 8468a4ce8510e..0e62918de63b3 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -137,21 +137,12 @@ static inline void ASSERT_RTNL_NET(struct net *net) ASSERT_RTNL(); } -static inline void *rcu_dereference_rtnl_net(struct net *net, void *p) -{ - return rcu_dereference_rtnl(p); -} - -static inline void *rtnl_net_dereference(struct net *net, void *p) -{ - return rtnl_dereference(p); -} - -static inline void *rcu_replace_pointer_rtnl_net(struct net *net, - void *rp, void *p) -{ - return rcu_replace_pointer_rtnl(rp, p); -} +#define rcu_dereference_rtnl_net(net, p) \ + rcu_dereference_rtnl(p) +#define rtnl_net_dereference(net, p) \ + rtnl_dereference(p) +#define rcu_replace_pointer_rtnl_net(net, rp, p) \ + rcu_replace_pointer_rtnl(rp, p) #endif static inline struct netdev_queue *dev_ingress_queue(struct net_device *dev)