On Fri, 5 Aug 2016, Robin Murphy wrote:

Hi Julia,

On 05/08/16 09:56, Julia Lawall wrote:

quoted

Use of_property_read_bool to check for the existence of a property.

This caught my eye since Rob told me off for doing the same recently[1].

quoted

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

// <smpl>
@@
expression e1,e2;
statement S2,S1;
@@
-       if (of_get_property(e1,e2,NULL))
+       if (of_property_read_bool(e1,e2))
        S1 else S2
// </smpl>

Signed-off-by: Julia Lawall <redacted>

---
 drivers/soc/ti/knav_qmss_queue.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soc/ti/knav_qmss_queue.c b/drivers/soc/ti/knav_qmss_queue.c
index b73e353..56b5d7c 100644
--- a/drivers/soc/ti/knav_qmss_queue.c
+++ b/drivers/soc/ti/knav_qmss_queue.c

@@ -1240,7 +1240,7 @@ static int knav_setup_queue_range(struct knav_device *kdev,
 	if (of_get_property(node, "qalloc-by-id", NULL))

According to the binding, "qalloc-by-id" _is_ a boolean property, so
this one really does deserve to be of_property_read_bool()...

quoted

 		range->flags |= RANGE_RESERVED;

-	if (of_get_property(node, "accumulator", NULL)) {
+	if (of_property_read_bool(node, "accumulator")) {

...whereas "accumulator" must have a value, so this isn't technically
appropriate. In general, most of these "if the property exists, read the
property and do stuff" checks are probably a sign of code that could be
simplified by refactoring the "do stuff" step to just specifically
handle the "read the property" step returning -EINVAL when it's not present.

Thanks for the very helpful feedback.  I will rethink the patch set in
light of this information.

julia

Robin.

[1]:https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg13375.html

quoted

 		ret = knav_init_acc_range(kdev, node, range);
 		if (ret < 0) {
 			devm_kfree(dev, range);


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