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can: af_can: do not access proto_tab directly use rcu_access_pointer instead 

"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>
zero-colors
Marc Kleine-Budde 2017-10-17 07:18:35 +02:00
parent 62c04647c6
commit cae1d5b78f
1 changed files with 3 additions and 3 deletions
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6
net/can/af_can.c
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@ -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);