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>

1 files changed, 4 insertions, 4 deletions

diff --git a/sound/firewire/fireface/ff-transaction.c b/sound/firewire/fireface/ff-transaction.c
index dd6c8e839647..332b29f8ed75 100644
--- a/sound/firewire/fireface/ff-transaction.c
+++ b/sound/firewire/fireface/ff-transaction.c
@@ -12,7 +12,7 @@ static void finish_transmit_midi_msg(struct snd_ff *ff, unsigned int port,
 				     int rcode)
 {
 	struct snd_rawmidi_substream *substream =
-				ACCESS_ONCE(ff->rx_midi_substreams[port]);
+				READ_ONCE(ff->rx_midi_substreams[port]);
 
 	if (rcode_is_permanent_error(rcode)) {
 		ff->rx_midi_error[port] = true;
@@ -60,7 +60,7 @@ static inline void fill_midi_buf(struct snd_ff *ff, unsigned int port,
 static void transmit_midi_msg(struct snd_ff *ff, unsigned int port)
 {
 	struct snd_rawmidi_substream *substream =
-			ACCESS_ONCE(ff->rx_midi_substreams[port]);
+			READ_ONCE(ff->rx_midi_substreams[port]);
 	u8 *buf = (u8 *)ff->msg_buf[port];
 	int i, len;
 
@@ -159,7 +159,7 @@ static void handle_midi_msg(struct fw_card *card, struct fw_request *request,
 		 */
 		index = (quad >> 8) & 0xff;
 		if (index > 0) {
-			substream = ACCESS_ONCE(ff->tx_midi_substreams[0]);
+			substream = READ_ONCE(ff->tx_midi_substreams[0]);
 			if (substream != NULL) {
 				byte = quad & 0xff;
 				snd_rawmidi_receive(substream, &byte, 1);
@@ -169,7 +169,7 @@ static void handle_midi_msg(struct fw_card *card, struct fw_request *request,
 		/* Message in second port. */
 		index = (quad >> 24) & 0xff;
 		if (index > 0) {
-			substream = ACCESS_ONCE(ff->tx_midi_substreams[1]);
+			substream = READ_ONCE(ff->tx_midi_substreams[1]);
 			if (substream != NULL) {
 				byte = (quad >> 16) & 0xff;
 				snd_rawmidi_receive(substream, &byte, 1);