can: af_can: do not access proto_tab directly use rcu_access_pointer instead (cae1d5b7) · Commits · 戴 / test

"proto_tab" is a RCU protected array, when directly accessing the array, sparse throws these warnings: CHECK /srv/work/frogger/socketcan/linux/net/can/af_can.c net/can/af_can.c:115:14: error: incompatible types in comparison expression (different address spaces) net/can/af_can.c:795:17: error: incompatible types in comparison expression (different address spaces) net/can/af_can.c:816:9: error: incompatible types in comparison expression (different address spaces) This patch fixes the problem by using rcu_access_pointer() and annotating "proto_tab" array as __rcu. Signed-off-by:

Marc Kleine-Budde <mkl@pengutronix.de>

net/can/af_can.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -78,7 +78,7 @@ MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
		static struct kmem_cache *rcv_cache __read_mostly;

		/* table of registered CAN protocols */
		static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
		static const struct can_proto __rcu *proto_tab[CAN_NPROTO] __read_mostly;
		static DEFINE_MUTEX(proto_tab_lock);

		static atomic_t skbcounter = ATOMIC_INIT(0);
		@@ -788,7 +788,7 @@ int can_proto_register(const struct can_proto *cp)

		mutex_lock(&proto_tab_lock);

		if (proto_tab[proto]) {
		if (rcu_access_pointer(proto_tab[proto])) {
		pr_err("can: protocol %d already registered\n", proto);
		err = -EBUSY;
		} else
		@@ -812,7 +812,7 @@ void can_proto_unregister(const struct can_proto *cp)
		int proto = cp->protocol;

		mutex_lock(&proto_tab_lock);
		BUG_ON(proto_tab[proto] != cp);
		BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
		RCU_INIT_POINTER(proto_tab[proto], NULL);
		mutex_unlock(&proto_tab_lock);

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