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, 3 insertions, 3 deletions

diff --git a/sound/firewire/tascam/tascam-transaction.c b/sound/firewire/tascam/tascam-transaction.c
index 8967c52f5032..2ad692dd4b13 100644
--- a/sound/firewire/tascam/tascam-transaction.c
+++ b/sound/firewire/tascam/tascam-transaction.c
@@ -148,7 +148,7 @@ static void async_midi_port_callback(struct fw_card *card, int rcode,
 				     void *callback_data)
 {
 	struct snd_fw_async_midi_port *port = callback_data;
-	struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
+	struct snd_rawmidi_substream *substream = READ_ONCE(port->substream);
 
 	/* This port is closed. */
 	if (substream == NULL)
@@ -173,7 +173,7 @@ static void midi_port_work(struct work_struct *work)
 {
 	struct snd_fw_async_midi_port *port =
 			container_of(work, struct snd_fw_async_midi_port, work);
-	struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
+	struct snd_rawmidi_substream *substream = READ_ONCE(port->substream);
 	int generation;
 
 	/* Under transacting or error state. */
@@ -282,7 +282,7 @@ static void handle_midi_tx(struct fw_card *card, struct fw_request *request,
 				bytes = 3;
 		}
 
-		substream = ACCESS_ONCE(tscm->tx_midi_substreams[port]);
+		substream = READ_ONCE(tscm->tx_midi_substreams[port]);
 		if (substream != NULL)
 			snd_rawmidi_receive(substream, b + 1, bytes);
 	}