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authorMark Rutland <mark.rutland@arm.com>2017-10-24 00:07:29 +0300
committerIngo Molnar <mingo@kernel.org>2017-10-25 12:01:08 +0300
commit6aa7de059173a986114ac43b8f50b297a86f09a8 (patch)
tree77666afe795e022914ca26433d61686c694dc4fd /net/ipv6
parentb03a0fe0c5e4b46dcd400d27395b124499554a71 (diff)
downloadlinux-6aa7de059173a986114ac43b8f50b297a86f09a8.tar.xz
locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()
Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6_tunnel.c8
-rw-r--r--net/ipv6/udp.c4
2 files changed, 6 insertions, 6 deletions
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index a1c24443cd9e..dab946554157 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -490,7 +490,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
if (!t)
goto out;
- tproto = ACCESS_ONCE(t->parms.proto);
+ tproto = READ_ONCE(t->parms.proto);
if (tproto != ipproto && tproto != 0)
goto out;
@@ -899,7 +899,7 @@ static int ipxip6_rcv(struct sk_buff *skb, u8 ipproto,
t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);
if (t) {
- u8 tproto = ACCESS_ONCE(t->parms.proto);
+ u8 tproto = READ_ONCE(t->parms.proto);
if (tproto != ipproto && tproto != 0)
goto drop;
@@ -1233,7 +1233,7 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
- tproto = ACCESS_ONCE(t->parms.proto);
+ tproto = READ_ONCE(t->parms.proto);
if (tproto != IPPROTO_IPIP && tproto != 0)
return -1;
@@ -1303,7 +1303,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
u8 tproto;
int err;
- tproto = ACCESS_ONCE(t->parms.proto);
+ tproto = READ_ONCE(t->parms.proto);
if ((tproto != IPPROTO_IPV6 && tproto != 0) ||
ip6_tnl_addr_conflict(t, ipv6h))
return -1;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 40d7234c27b9..3f30fa313bf2 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -606,7 +606,7 @@ static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
*/
/* if we're overly short, let UDP handle it */
- encap_rcv = ACCESS_ONCE(up->encap_rcv);
+ encap_rcv = READ_ONCE(up->encap_rcv);
if (encap_rcv) {
int ret;
@@ -1432,7 +1432,7 @@ void udpv6_destroy_sock(struct sock *sk)
if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
void (*encap_destroy)(struct sock *sk);
- encap_destroy = ACCESS_ONCE(up->encap_destroy);
+ encap_destroy = READ_ONCE(up->encap_destroy);
if (encap_destroy)
encap_destroy(sk);
}