From: Mark Rutland <mark.rutland@xxxxxxx>
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 currently harmful.
However, for some features it is necessary to instrument reads and
writes separately, which is not possible with ACCESS_ONCE(). This
distinction is critical to correct operation.
It's possible to transform the bulk of kernel code using the Coccinelle
script below. However, this doesn't handle comments, leaving references
to ACCESS_ONCE() instances which have been removed. As a preparatory
step, this patch converts the Altera EDAC code and comments to use
{READ,WRITE}_ONCE() consistently.
----
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@xxxxxxx>
Acked-by: Thor Thayer <thor.thayer@xxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
---
drivers/edac/altera_edac.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
index 346c4987b284..11d6419788c2 100644
--- a/drivers/edac/altera_edac.c
+++ b/drivers/edac/altera_edac.c
@@ -175,11 +175,11 @@ static ssize_t altr_sdr_mc_err_inject_write(struct file *file,
/*
* To trigger the error, we need to read the data back
* (the data was written with errors above).
- * The ACCESS_ONCE macros and printk are used to prevent the
+ * The READ_ONCE macros and printk are used to prevent the
* the compiler optimizing these reads out.
*/
- reg = ACCESS_ONCE(ptemp[0]);
- read_reg = ACCESS_ONCE(ptemp[1]);
+ reg = READ_ONCE(ptemp[0]);
+ read_reg = READ_ONCE(ptemp[1]);
/* Force Read */
rmb();
@@ -618,7 +618,7 @@ static ssize_t altr_edac_device_trig(struct file *file,
for (i = 0; i < (priv->trig_alloc_sz / sizeof(*ptemp)); i++) {
/* Read data so we're in the correct state */
rmb();
- if (ACCESS_ONCE(ptemp[i]))
+ if (READ_ONCE(ptemp[i]))
result = -1;
/* Toggle Error bit (it is latched), leave ECC enabled */
writel(error_mask, (drvdata->base + priv->set_err_ofst));
@@ -635,7 +635,7 @@ static ssize_t altr_edac_device_trig(struct file *file,
/* Read out written data. ECC error caused here */
for (i = 0; i < ALTR_TRIGGER_READ_WRD_CNT; i++)
- if (ACCESS_ONCE(ptemp[i]) != i)
+ if (READ_ONCE(ptemp[i]) != i)
edac_printk(KERN_ERR, EDAC_DEVICE,
"Read doesn't match written data\n");
--
2.5.2
