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, 11 insertions, 12 deletions

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 3fc581a5ad62..4a1dc145327b 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -376,7 +376,7 @@ static void update_pcm_pointers(struct amdtp_stream *s,
 	ptr = s->pcm_buffer_pointer + frames;
 	if (ptr >= pcm->runtime->buffer_size)
 		ptr -= pcm->runtime->buffer_size;
-	ACCESS_ONCE(s->pcm_buffer_pointer) = ptr;
+	WRITE_ONCE(s->pcm_buffer_pointer, ptr);
 
 	s->pcm_period_pointer += frames;
 	if (s->pcm_period_pointer >= pcm->runtime->period_size) {
@@ -388,7 +388,7 @@ static void update_pcm_pointers(struct amdtp_stream *s,
 static void pcm_period_tasklet(unsigned long data)
 {
 	struct amdtp_stream *s = (void *)data;
-	struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);
+	struct snd_pcm_substream *pcm = READ_ONCE(s->pcm);
 
 	if (pcm)
 		snd_pcm_period_elapsed(pcm);
@@ -453,7 +453,7 @@ static int handle_out_packet(struct amdtp_stream *s,
 		s->data_block_counter =
 				(s->data_block_counter + data_blocks) & 0xff;
 
-	buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
+	buffer[0] = cpu_to_be32(READ_ONCE(s->source_node_id_field) |
 				(s->data_block_quadlets << CIP_DBS_SHIFT) |
 				((s->sph << CIP_SPH_SHIFT) & CIP_SPH_MASK) |
 				s->data_block_counter);
@@ -472,7 +472,7 @@ static int handle_out_packet(struct amdtp_stream *s,
 	if (queue_out_packet(s, payload_length) < 0)
 		return -EIO;
 
-	pcm = ACCESS_ONCE(s->pcm);
+	pcm = READ_ONCE(s->pcm);
 	if (pcm && pcm_frames > 0)
 		update_pcm_pointers(s, pcm, pcm_frames);
 
@@ -504,7 +504,7 @@ static int handle_out_packet_without_header(struct amdtp_stream *s,
 	if (queue_out_packet(s, payload_length) < 0)
 		return -EIO;
 
-	pcm = ACCESS_ONCE(s->pcm);
+	pcm = READ_ONCE(s->pcm);
 	if (pcm && pcm_frames > 0)
 		update_pcm_pointers(s, pcm, pcm_frames);
 
@@ -621,7 +621,7 @@ end:
 	if (queue_in_packet(s) < 0)
 		return -EIO;
 
-	pcm = ACCESS_ONCE(s->pcm);
+	pcm = READ_ONCE(s->pcm);
 	if (pcm && pcm_frames > 0)
 		update_pcm_pointers(s, pcm, pcm_frames);
 
@@ -649,7 +649,7 @@ static int handle_in_packet_without_header(struct amdtp_stream *s,
 	if (queue_in_packet(s) < 0)
 		return -EIO;
 
-	pcm = ACCESS_ONCE(s->pcm);
+	pcm = READ_ONCE(s->pcm);
 	if (pcm && pcm_frames > 0)
 		update_pcm_pointers(s, pcm, pcm_frames);
 
@@ -947,7 +947,7 @@ unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
 	if (!in_interrupt() && amdtp_stream_running(s))
 		fw_iso_context_flush_completions(s->context);
 
-	return ACCESS_ONCE(s->pcm_buffer_pointer);
+	return READ_ONCE(s->pcm_buffer_pointer);
 }
 EXPORT_SYMBOL(amdtp_stream_pcm_pointer);
 
@@ -977,9 +977,8 @@ EXPORT_SYMBOL(amdtp_stream_pcm_ack);
 void amdtp_stream_update(struct amdtp_stream *s)
 {
 	/* Precomputing. */
-	ACCESS_ONCE(s->source_node_id_field) =
-		(fw_parent_device(s->unit)->card->node_id << CIP_SID_SHIFT) &
-								CIP_SID_MASK;
+	WRITE_ONCE(s->source_node_id_field,
+                   (fw_parent_device(s->unit)->card->node_id << CIP_SID_SHIFT) & CIP_SID_MASK);
 }
 EXPORT_SYMBOL(amdtp_stream_update);
 
@@ -1022,7 +1021,7 @@ void amdtp_stream_pcm_abort(struct amdtp_stream *s)
 {
 	struct snd_pcm_substream *pcm;
 
-	pcm = ACCESS_ONCE(s->pcm);
+	pcm = READ_ONCE(s->pcm);
 	if (pcm)
 		snd_pcm_stop_xrun(pcm);
 }