From: Johan Hovold <johan@kernel.org>
To: Rob Herring <robh+dt@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Frank Rowand <frowand.list@gmail.com>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
Johan Hovold <johan@kernel.org>
Subject: [PATCH 1/9] of: add helper to lookup compatible child node
Date: Wed, 22 Aug 2018 12:55:39 +0200 [thread overview]
Message-ID: <20180822105547.9634-2-johan@kernel.org> (raw)
In-Reply-To: <20180822105547.9634-1-johan@kernel.org>
Add of_get_compatible_child() helper that can be used to lookup
compatible child nodes.
Several drivers currently use of_find_compatible_node() to lookup child
nodes while failing to notice that the of_find_ functions search the
entire tree depth-first and therefore can match unrelated (non-child)
nodes. The fact that these functions also drop a reference to the node
they start searching from (e.g. the parent node) is typically also
overlooked, something which can lead to use-after-free bugs.
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/of/base.c | 25 +++++++++++++++++++++++++
include/linux/of.h | 8 ++++++++
2 files changed, 33 insertions(+)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 466e3c8582f0..bc420d2aa5f5 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -719,6 +719,31 @@ struct device_node *of_get_next_available_child(const struct device_node *node,
}
EXPORT_SYMBOL(of_get_next_available_child);
+/**
+ * of_get_compatible_child - Find compatible child node
+ * @parent: parent node
+ * @compatible: compatible string
+ *
+ * Lookup child node whose compatible property contains the given compatible
+ * string.
+ *
+ * Returns a node pointer with refcount incremented, use of_node_put() on it
+ * when done; or NULL if not found.
+ */
+struct device_node *of_get_compatible_child(const struct device_node *parent,
+ const char *compatible)
+{
+ struct device_node *child;
+
+ for_each_child_of_node(parent, child) {
+ if (of_device_is_compatible(child, compatible))
+ break;
+ }
+
+ return child;
+}
+EXPORT_SYMBOL(of_get_compatible_child);
+
/**
* of_get_child_by_name - Find the child node by name for a given parent
* @node: parent node
diff --git a/include/linux/of.h b/include/linux/of.h
index 4d25e4f952d9..c22982fc1bff 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -290,6 +290,8 @@ extern struct device_node *of_get_next_child(const struct device_node *node,
extern struct device_node *of_get_next_available_child(
const struct device_node *node, struct device_node *prev);
+extern struct device_node *of_get_compatible_child(const struct device_node *parent,
+ const char *compatible);
extern struct device_node *of_get_child_by_name(const struct device_node *node,
const char *name);
@@ -632,6 +634,12 @@ static inline bool of_have_populated_dt(void)
return false;
}
+static struct device_node *of_get_compatible_child(const struct device_node *parent,
+ const char *compatible)
+{
+ return NULL;
+}
+
static inline struct device_node *of_get_child_by_name(
const struct device_node *node,
const char *name)
--
2.18.0
next prev parent reply other threads:[~2018-08-22 10:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-22 10:55 [PATCH 0/9] of: fix compatible-child-node lookups Johan Hovold
2018-08-22 10:55 ` Johan Hovold [this message]
2018-08-23 3:17 ` [PATCH 1/9] of: add helper to lookup compatible child node kbuild test robot
2018-08-23 7:39 ` Johan Hovold
2018-08-22 10:55 ` [PATCH 2/9] drm/mediatek: fix OF sibling-node lookup Johan Hovold
2018-08-22 10:55 ` [PATCH 3/9] drm/msm: fix OF child-node lookup Johan Hovold
2018-08-22 14:41 ` Rob Herring
2018-08-22 10:55 ` [PATCH 4/9] mmc: meson-mx-sdio: " Johan Hovold
2018-08-23 18:50 ` Martin Blumenstingl
2018-08-24 6:41 ` Johan Hovold
2018-08-22 10:55 ` [PATCH 5/9] mtd: nand: atmel: " Johan Hovold
2018-08-22 10:55 ` [PATCH 6/9] net: bcmgenet: " Johan Hovold
2018-08-22 10:55 ` [PATCH 7/9] net: stmmac: dwmac-sun8i: " Johan Hovold
2018-08-22 10:55 ` [PATCH 8/9] NFC: nfcmrvl_uart: " Johan Hovold
2018-08-22 10:55 ` [PATCH 9/9] power: supply: twl4030-charger: fix OF sibling-node lookup Johan Hovold
2018-08-22 21:36 ` Sebastian Reichel
2018-08-23 7:40 ` Johan Hovold
2018-08-22 14:32 ` [PATCH 0/9] of: fix compatible-child-node lookups Rob Herring
2018-08-22 14:46 ` Johan Hovold
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