diff options
authorMark Rutland <mark.rutland@arm.com>2017-10-23 14:07:12 -0700
committerIngo Molnar <mingo@kernel.org>2017-10-25 11:00:56 +0200
commit332efa6374de75c622b782569b16bb50fd722cf5 (patch)
parentd3e632f07b6e637d3643081873867ecb6433b2ce (diff)
locking/atomics, EDAC/altera: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()
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@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Thor Thayer <thor.thayer@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> 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: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-2-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 files 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 */
@@ -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 */
- 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");

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