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, 9 insertions, 9 deletions

diff --git a/sound/firewire/isight.c b/sound/firewire/isight.c
index 5826aa8362f1..46092fa3ff9b 100644
--- a/sound/firewire/isight.c
+++ b/sound/firewire/isight.c
@@ -96,7 +96,7 @@ static void isight_update_pointers(struct isight *isight, unsigned int count)
 	ptr += count;
 	if (ptr >= runtime->buffer_size)
 		ptr -= runtime->buffer_size;
-	ACCESS_ONCE(isight->buffer_pointer) = ptr;
+	WRITE_ONCE(isight->buffer_pointer, ptr);
 
 	isight->period_counter += count;
 	if (isight->period_counter >= runtime->period_size) {
@@ -111,7 +111,7 @@ static void isight_samples(struct isight *isight,
 	struct snd_pcm_runtime *runtime;
 	unsigned int count1;
 
-	if (!ACCESS_ONCE(isight->pcm_running))
+	if (!READ_ONCE(isight->pcm_running))
 		return;
 
 	runtime = isight->pcm->runtime;
@@ -131,7 +131,7 @@ static void isight_samples(struct isight *isight,
 
 static void isight_pcm_abort(struct isight *isight)
 {
-	if (ACCESS_ONCE(isight->pcm_active))
+	if (READ_ONCE(isight->pcm_active))
 		snd_pcm_stop_xrun(isight->pcm);
 }
 
@@ -141,7 +141,7 @@ static void isight_dropped_samples(struct isight *isight, unsigned int total)
 	u32 dropped;
 	unsigned int count1;
 
-	if (!ACCESS_ONCE(isight->pcm_running))
+	if (!READ_ONCE(isight->pcm_running))
 		return;
 
 	runtime = isight->pcm->runtime;
@@ -293,7 +293,7 @@ static int isight_hw_params(struct snd_pcm_substream *substream,
 	if (err < 0)
 		return err;
 
-	ACCESS_ONCE(isight->pcm_active) = true;
+	WRITE_ONCE(isight->pcm_active, true);
 
 	return 0;
 }
@@ -331,7 +331,7 @@ static int isight_hw_free(struct snd_pcm_substream *substream)
 {
 	struct isight *isight = substream->private_data;
 
-	ACCESS_ONCE(isight->pcm_active) = false;
+	WRITE_ONCE(isight->pcm_active, false);
 
 	mutex_lock(&isight->mutex);
 	isight_stop_streaming(isight);
@@ -424,10 +424,10 @@ static int isight_trigger(struct snd_pcm_substream *substream, int cmd)
 
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
-		ACCESS_ONCE(isight->pcm_running) = true;
+		WRITE_ONCE(isight->pcm_running, true);
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
-		ACCESS_ONCE(isight->pcm_running) = false;
+		WRITE_ONCE(isight->pcm_running, false);
 		break;
 	default:
 		return -EINVAL;
@@ -439,7 +439,7 @@ static snd_pcm_uframes_t isight_pointer(struct snd_pcm_substream *substream)
 {
 	struct isight *isight = substream->private_data;
 
-	return ACCESS_ONCE(isight->buffer_pointer);
+	return READ_ONCE(isight->buffer_pointer);
 }
 
 static int isight_create_pcm(struct isight *isight)