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>

2 files changed, 4 insertions, 4 deletions

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index c02cc817a490..1ed9529e7bd1 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -1378,7 +1378,7 @@ int bond_tlb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
 				unsigned int count;
 
 				slaves = rcu_dereference(bond->slave_arr);
-				count = slaves ? ACCESS_ONCE(slaves->count) : 0;
+				count = slaves ? READ_ONCE(slaves->count) : 0;
 				if (likely(count))
 					tx_slave = slaves->arr[hash_index %
 							       count];
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index c99dc59d729b..af51b90cecbb 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1167,7 +1167,7 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
 	slave = bond_slave_get_rcu(skb->dev);
 	bond = slave->bond;
 
-	recv_probe = ACCESS_ONCE(bond->recv_probe);
+	recv_probe = READ_ONCE(bond->recv_probe);
 	if (recv_probe) {
 		ret = recv_probe(skb, bond, slave);
 		if (ret == RX_HANDLER_CONSUMED) {
@@ -3810,7 +3810,7 @@ static int bond_xmit_roundrobin(struct sk_buff *skb, struct net_device *bond_dev
 		else
 			bond_xmit_slave_id(bond, skb, 0);
 	} else {
-		int slave_cnt = ACCESS_ONCE(bond->slave_cnt);
+		int slave_cnt = READ_ONCE(bond->slave_cnt);
 
 		if (likely(slave_cnt)) {
 			slave_id = bond_rr_gen_slave_id(bond);
@@ -3972,7 +3972,7 @@ static int bond_3ad_xor_xmit(struct sk_buff *skb, struct net_device *dev)
 	unsigned int count;
 
 	slaves = rcu_dereference(bond->slave_arr);
-	count = slaves ? ACCESS_ONCE(slaves->count) : 0;
+	count = slaves ? READ_ONCE(slaves->count) : 0;
 	if (likely(count)) {
 		slave = slaves->arr[bond_xmit_hash(bond, skb) % count];
 		bond_dev_queue_xmit(bond, skb, slave->dev);