Use DEVICE_ATTR_RW for read-write attributes.  This simplifies the
source code, improves readbility, and reduces the chance of
inconsistencies.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@rw@
declarer name DEVICE_ATTR;
identifier x,x_show,x_store;
@@

DEVICE_ATTR(x, \(0644\|S_IRUGO|S_IWUSR\), x_show, x_store);

@script:ocaml@
x << rw.x;
x_show << rw.x_show;
x_store << rw.x_store;
@@

if not (x^"_show" = x_show && x^"_store" = x_store)
then Coccilib.include_match false

@@
declarer name DEVICE_ATTR_RW;
identifier rw.x,rw.x_show,rw.x_store;
@@

- DEVICE_ATTR(x, \(0644\|S_IRUGO|S_IWUSR\), x_show, x_store);
+ DEVICE_ATTR_RW(x);
// </smpl>

Signed-off-by: Julia Lawall <redacted>

---
 arch/powerpc/kernel/iommu.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 5f202a5..32f18b5 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c

@@ -127,8 +127,7 @@ static ssize_t fail_iommu_store(struct device *dev,
 	return count;
 }
 
-static DEVICE_ATTR(fail_iommu, S_IRUGO|S_IWUSR, fail_iommu_show,
-		   fail_iommu_store);
+static DEVICE_ATTR_RW(fail_iommu);
 
 static int fail_iommu_bus_notify(struct notifier_block *nb,
 				 unsigned long action, void *data)