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SubjectRe: [PATCH 2/3] of: Make of_find_node_by_path() handle /aliases
Date
On Tue, 20 May 2014 19:55:45 -0700, Frank Rowand <frowand.list@gmail.com> wrote:
> On 5/13/2014 7:58 AM, Grant Likely wrote:
>
> > Make of_find_node_by_path() handle aliases as prefixes. To make this
>
> > work the name search is refactored to search by path component instead
>
> > of by full string. This should be a more efficient search, and it makes
>
> > it possible to start a search at a subnode of a tree.
>
> >
>
> > Signed-off-by: David Daney <david.daney@cavium.com>
>
> > Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
>
> > [grant.likely: Rework to not require allocating at runtime]
>
> > Acked-by: Rob Herring <robh@kernel.org>
>
> > Signed-off-by: Grant Likely <grant.likely@linaro.org>
>
> > ---
>
> > drivers/of/base.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++----
>
> > 1 file changed, 56 insertions(+), 4 deletions(-)
>
>
>
> Was this patch created against a tree that has modifications to device tree
>
> locking?
> I get a hang due to deadlock when I apply it. Patch to verify the
> cause is below.

Ummm... I may have forgotten to enable CONFIG_LOCKDEP when testing. Try
the following fix, and can you please pass me that brown paper bag.

g.

commit 35e9c5ae6c3d0b5eb91579f397d8e1ecb95ee711
Author: Grant Likely <grant.likely@linaro.org>
Date: Thu May 22 01:04:17 2014 +0900

dt: Create unlocked version of for_each_child_of_node()

When iterating over nodes, sometimes it needs to be done when the DT
lock is already held. This patch makes an unlocked version of the
for_each_child_of_node() macro.

Signed-off-by: Grant Likely <grant.likely@linaro.org>

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 8900d378c07e..c05a143b6a70 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -695,6 +695,22 @@ struct device_node *of_get_next_parent(struct device_node *node)
}
EXPORT_SYMBOL(of_get_next_parent);

+#define __for_each_child_of_node(parent, child) \
+ for (child = __of_get_next_child(parent, NULL); child != NULL; \
+ child = __of_get_next_child(parent, child))
+static struct device_node *__of_get_next_child(const struct device_node *node,
+ struct device_node *prev)
+{
+ struct device_node *next;
+
+ next = prev ? prev->sibling : node->child;
+ for (; next; next = next->sibling)
+ if (of_node_get(next))
+ break;
+ of_node_put(prev);
+ return next;
+}
+
/**
* of_get_next_child - Iterate a node childs
* @node: parent node
@@ -710,11 +726,7 @@ struct device_node *of_get_next_child(const struct device_node *node,
unsigned long flags;

raw_spin_lock_irqsave(&devtree_lock, flags);
- next = prev ? prev->sibling : node->child;
- for (; next; next = next->sibling)
- if (of_node_get(next))
- break;
- of_node_put(prev);
+ next = __of_get_next_child(node, prev);
raw_spin_unlock_irqrestore(&devtree_lock, flags);
return next;
}
@@ -780,7 +792,7 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
if (!len)
return parent;

- for_each_child_of_node(parent, child) {
+ __for_each_child_of_node(parent, child) {
const char *name = strrchr(child->full_name, '/');
if (WARN(!name, "malformed device_node %s\n", child->full_name))
continue;


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