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>

2 files changed, 3 insertions, 3 deletions

diff --git a/drivers/crypto/caam/jr.c b/drivers/crypto/caam/jr.c
index d258953ff488..f4f258075b89 100644
--- a/drivers/crypto/caam/jr.c
+++ b/drivers/crypto/caam/jr.c
@@ -172,7 +172,7 @@ static void caam_jr_dequeue(unsigned long devarg)
 
 	while (rd_reg32(&jrp->rregs->outring_used)) {
 
-		head = ACCESS_ONCE(jrp->head);
+		head = READ_ONCE(jrp->head);
 
 		spin_lock(&jrp->outlock);
 
@@ -341,7 +341,7 @@ int caam_jr_enqueue(struct device *dev, u32 *desc,
 	spin_lock_bh(&jrp->inplock);
 
 	head = jrp->head;
-	tail = ACCESS_ONCE(jrp->tail);
+	tail = READ_ONCE(jrp->tail);
 
 	if (!rd_reg32(&jrp->rregs->inpring_avail) ||
 	    CIRC_SPACE(head, tail, JOBR_DEPTH) <= 0) {
diff --git a/drivers/crypto/nx/nx-842-powernv.c b/drivers/crypto/nx/nx-842-powernv.c
index 874ddf5e9087..0f20f5ec9617 100644
--- a/drivers/crypto/nx/nx-842-powernv.c
+++ b/drivers/crypto/nx/nx-842-powernv.c
@@ -193,7 +193,7 @@ static int wait_for_csb(struct nx842_workmem *wmem,
 	ktime_t start = wmem->start, now = ktime_get();
 	ktime_t timeout = ktime_add_ms(start, CSB_WAIT_MAX);
 
-	while (!(ACCESS_ONCE(csb->flags) & CSB_V)) {
+	while (!(READ_ONCE(csb->flags) & CSB_V)) {
 		cpu_relax();
 		now = ktime_get();
 		if (ktime_after(now, timeout))