A cast is often needed to call some OF functions, removing
the 'const' attribute.
This patchset makes 'const' the device node pointers of the functions
of_clk_get() and of_node_put() and also removes some useless casts
in the sound/soc tree.
Jean-Francois Moine (2):
of: Make const the device node pointers in of_clk_get and of_node_put
ASoC: Remove useless casts
drivers/clk/clkdev.c | 2 +-
drivers/of/dynamic.c | 2 +-
include/linux/clk.h | 4 ++--
include/linux/of.h | 4 ++--
sound/soc/generic/simple-card.c | 7 ++-----
sound/soc/samsung/odroidx2_max98090.c | 4 ++--
sound/soc/ux500/mop500.c | 6 ++----
7 files changed, 12 insertions(+), 17 deletions(-)
--
2.1.3
Some device nodes are sometimes referenced by const pointers.
This patch avoids to cast these pointers when calling the functions
of_clk_get() and of_node_put().
Signed-off-by: Jean-Francois Moine <[email protected]>
---
drivers/clk/clkdev.c | 2 +-
drivers/of/dynamic.c | 2 +-
include/linux/clk.h | 4 ++--
include/linux/of.h | 4 ++--
4 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index da4bda8..eaee11e 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -53,7 +53,7 @@ struct clk *of_clk_get_by_clkspec(struct of_phandle_args *clkspec)
return clk;
}
-struct clk *of_clk_get(struct device_node *np, int index)
+struct clk *of_clk_get(const struct device_node *np, int index)
{
struct of_phandle_args clkspec;
struct clk *clk;
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index f297891..64eb5ba 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -34,7 +34,7 @@ EXPORT_SYMBOL(of_node_get);
* @node: Node to dec refcount, NULL is supported to simplify writing of
* callers
*/
-void of_node_put(struct device_node *node)
+void of_node_put(const struct device_node *node)
{
if (node)
kobject_put(&node->kobj);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index c7f258a..4e077a4 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -425,11 +425,11 @@ struct device_node;
struct of_phandle_args;
#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
-struct clk *of_clk_get(struct device_node *np, int index);
+struct clk *of_clk_get(const struct device_node *np, int index);
struct clk *of_clk_get_by_name(struct device_node *np, const char *name);
struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);
#else
-static inline struct clk *of_clk_get(struct device_node *np, int index)
+static inline struct clk *of_clk_get(const struct device_node *np, int index)
{
return ERR_PTR(-ENOENT);
}
diff --git a/include/linux/of.h b/include/linux/of.h
index 6545e7a..b738681 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -95,14 +95,14 @@ static inline int of_node_is_attached(struct device_node *node)
#ifdef CONFIG_OF_DYNAMIC
extern struct device_node *of_node_get(struct device_node *node);
-extern void of_node_put(struct device_node *node);
+extern void of_node_put(const struct device_node *node);
#else /* CONFIG_OF_DYNAMIC */
/* Dummy ref counting routines - to be implemented later */
static inline struct device_node *of_node_get(struct device_node *node)
{
return node;
}
-static inline void of_node_put(struct device_node *node) { }
+static inline void of_node_put(const struct device_node *node) { }
#endif /* !CONFIG_OF_DYNAMIC */
#ifdef CONFIG_OF
--
2.1.3
There is no need to cast the cpu_of_node or codec_of_node of the
dai_links when calling of_put_node.
Signed-off-by: Jean-Francois Moine <[email protected]>
---
sound/soc/generic/simple-card.c | 7 ++-----
sound/soc/samsung/odroidx2_max98090.c | 4 ++--
sound/soc/ux500/mop500.c | 6 ++----
3 files changed, 6 insertions(+), 11 deletions(-)
diff --git a/sound/soc/generic/simple-card.c b/sound/soc/generic/simple-card.c
index cd49d50..3e3fec4 100644
--- a/sound/soc/generic/simple-card.c
+++ b/sound/soc/generic/simple-card.c
@@ -457,16 +457,13 @@ static int asoc_simple_card_unref(struct platform_device *pdev)
{
struct snd_soc_card *card = platform_get_drvdata(pdev);
struct snd_soc_dai_link *dai_link;
- struct device_node *np;
int num_links;
for (num_links = 0, dai_link = card->dai_link;
num_links < card->num_links;
num_links++, dai_link++) {
- np = (struct device_node *) dai_link->cpu_of_node;
- of_node_put(np);
- np = (struct device_node *) dai_link->codec_of_node;
- of_node_put(np);
+ of_node_put(dai_link->cpu_of_node);
+ of_node_put(dai_link->codec_of_node);
}
return 0;
}
diff --git a/sound/soc/samsung/odroidx2_max98090.c b/sound/soc/samsung/odroidx2_max98090.c
index 3c8f604..d7640e7 100644
--- a/sound/soc/samsung/odroidx2_max98090.c
+++ b/sound/soc/samsung/odroidx2_max98090.c
@@ -153,8 +153,8 @@ static int odroidx2_audio_remove(struct platform_device *pdev)
snd_soc_unregister_card(card);
- of_node_put((struct device_node *)odroidx2_dai[0].cpu_of_node);
- of_node_put((struct device_node *)odroidx2_dai[0].codec_of_node);
+ of_node_put(odroidx2_dai[0].cpu_of_node);
+ of_node_put(odroidx2_dai[0].codec_of_node);
return 0;
}
diff --git a/sound/soc/ux500/mop500.c b/sound/soc/ux500/mop500.c
index b3b66aa..ea9ba284 100644
--- a/sound/soc/ux500/mop500.c
+++ b/sound/soc/ux500/mop500.c
@@ -64,11 +64,9 @@ static void mop500_of_node_put(void)
for (i = 0; i < 2; i++) {
if (mop500_dai_links[i].cpu_of_node)
- of_node_put((struct device_node *)
- mop500_dai_links[i].cpu_of_node);
+ of_node_put(mop500_dai_links[i].cpu_of_node);
if (mop500_dai_links[i].codec_of_node)
- of_node_put((struct device_node *)
- mop500_dai_links[i].codec_of_node);
+ of_node_put(mop500_dai_links[i].codec_of_node);
}
}
--
2.1.3
On Sat, Nov 08, 2014 at 07:33:22PM +0100, Jean-Francois Moine wrote:
> Some device nodes are sometimes referenced by const pointers.
>
> This patch avoids to cast these pointers when calling the functions
> of_clk_get() and of_node_put().
NAK. Firstly, of_node_put contains a kref, which is /definitely/ not
a const item when kobject_put() is called on it. Inside the kobject
is a kref, which kobject_put() will call kref_put() on. kref_put()
in turn will internally call atomic_sub_and_test() on a value embedded
within the kref struct.
Ergo, of_node_put() modifies the struct device_node contents. Therefore,
of_node_put() definitely not treating the data pointed to as read-only,
and therefore it is completely inappropriate for it to be marked "const".
What this then means is that it fundamentally undermines the idea of
storing the pointer to a device_node as a const pointer, as the device
node must always be modified when you're done with it (because it's a
ref-counted structure.) So, having it const in your code is a bug.
What this also means is that every other place that you've added const
below is also very dubious.
--
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.
On Sun, 9 Nov 2014 18:50:19 +0000
Russell King - ARM Linux <[email protected]> wrote:
> What this then means is that it fundamentally undermines the idea of
> storing the pointer to a device_node as a const pointer, as the device
> node must always be modified when you're done with it (because it's a
> ref-counted structure.) So, having it const in your code is a bug.
>
> What this also means is that every other place that you've added const
> below is also very dubious.
Thanks for the explanation.
The correct patch will be simpler: in the ASoC structures, I found only
three places where the device_node pointer is const.
--
Ken ar c'hentañ | ** Breizh ha Linux atav! **
Jef | http://moinejf.free.fr/