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, 6 insertions, 6 deletions

diff --git a/sound/firewire/oxfw/oxfw-scs1x.c b/sound/firewire/oxfw/oxfw-scs1x.c
index 02d595665898..f33497cdc706 100644
--- a/sound/firewire/oxfw/oxfw-scs1x.c
+++ b/sound/firewire/oxfw/oxfw-scs1x.c
@@ -112,7 +112,7 @@ static void handle_hss(struct fw_card *card, struct fw_request *request,
 	}
 
 	if (length >= 1) {
-		stream = ACCESS_ONCE(scs->input);
+		stream = READ_ONCE(scs->input);
 		if (stream)
 			midi_input_packet(scs, stream, data, length);
 	}
@@ -183,7 +183,7 @@ static void scs_output_work(struct work_struct *work)
 	if (scs->transaction_running)
 		return;
 
-	stream = ACCESS_ONCE(scs->output);
+	stream = READ_ONCE(scs->output);
 	if (!stream || scs->error) {
 		scs->output_idle = true;
 		wake_up(&scs->idle_wait);
@@ -291,9 +291,9 @@ static void midi_capture_trigger(struct snd_rawmidi_substream *stream, int up)
 
 	if (up) {
 		scs->input_escape_count = 0;
-		ACCESS_ONCE(scs->input) = stream;
+		WRITE_ONCE(scs->input, stream);
 	} else {
-		ACCESS_ONCE(scs->input) = NULL;
+		WRITE_ONCE(scs->input, NULL);
 	}
 }
 
@@ -319,10 +319,10 @@ static void midi_playback_trigger(struct snd_rawmidi_substream *stream, int up)
 		scs->transaction_bytes = 0;
 		scs->error = false;
 
-		ACCESS_ONCE(scs->output) = stream;
+		WRITE_ONCE(scs->output, stream);
 		schedule_work(&scs->work);
 	} else {
-		ACCESS_ONCE(scs->output) = NULL;
+		WRITE_ONCE(scs->output, NULL);
 	}
 }
 static void midi_playback_drain(struct snd_rawmidi_substream *stream)