[PATCH] Removes OF_SELFTEST dependency on OF_DYNAMIC

[PATCH] Removes OF_SELFTEST dependency on OF_DYNAMIC

[Gaurav Minocha]

This patch is used to remove the selftests dependency on
OF_DYNAMIC config flag. Now, it executes only the tests
that do not depend upon CONFIG_OF_DYNAMIC. Also, it
defines the functions to attach and detach the node
if OF_DYNAMIC flag isn't enabled.

Tested with and without OF_DYNAMIC enabled.

Signed-off-by: Gaurav Minocha <gaurav.minocha.os-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/of/Kconfig    |    1 -
 drivers/of/selftest.c |  103 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+), 1 deletion(-)

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 5160c4e..1fe3805 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -10,7 +10,6 @@ menu "Device Tree and Open Firmware support"
 config OF_SELFTEST
 	bool "Device Tree Runtime self tests"
 	depends on OF_IRQ && OF_EARLY_FLATTREE
-	select OF_DYNAMIC
 	help
 	  This option builds in test cases for the device tree infrastructure
 	  that are executed once at boot time, and the results dumped to the
diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c
index a737cb5..7330007 100644
--- a/drivers/of/selftest.c
+++ b/drivers/of/selftest.c
@@ -39,6 +39,103 @@ static bool selftest_live_tree;
 	} \
 }
 
+#if !defined(CONFIG_OF_DYNAMIC)
+void __of_attach_node(struct device_node *np)
+{
+	const __be32 *phandle;
+	int sz;
+
+	np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
+	np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
+	phandle = __of_get_property(np, "phandle", &sz);
+	if (!phandle)
+		phandle = __of_get_property(np, "linux,phandle", &sz);
+	if (IS_ENABLED(PPC_PSERIES) && !phandle)
+		phandle = __of_get_property(np, "ibm,phandle", &sz);
+	np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;
+	np->sibling = np->parent->child;
+	np->allnext = np->parent->allnext;
+	np->parent->allnext = np;
+	np->parent->child = np;
+	of_node_clear_flag(np, OF_DETACHED);
+}
+
+/**
+ * of_attach_node() - Plug a device node into the tree and global list.
+ */
+int of_attach_node(struct device_node *np)
+{
+	unsigned long flags;
+
+	mutex_lock(&of_mutex);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
+	__of_attach_node(np);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+	mutex_unlock(&of_mutex);
+
+	return 0;
+}
+
+void __of_detach_node(struct device_node *np)
+{
+	struct device_node *parent;
+
+	if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
+		return;
+
+	parent = np->parent;
+	if (WARN_ON(!parent))
+		return;
+
+	if (of_allnodes == np)
+		of_allnodes = np->allnext;
+	else {
+		struct device_node *prev;
+
+		for (prev = of_allnodes;
+		     prev->allnext != np;
+		     prev = prev->allnext)
+			;
+		prev->allnext = np->allnext;
+	}
+
+	if (parent->child == np)
+		parent->child = np->sibling;
+	else {
+		struct device_node *prevsib;
+
+		for (prevsib = np->parent->child;
+		     prevsib->sibling != np;
+		     prevsib = prevsib->sibling)
+			;
+		prevsib->sibling = np->sibling;
+	}
+
+	of_node_set_flag(np, OF_DETACHED);
+}
+
+/**
+ * of_detach_node() - "Unplug" a node from the device tree.
+ *
+ * The caller must hold a reference to the node.  The memory associated with
+ * the node is not freed until its refcount goes to zero.
+ */
+int of_detach_node(struct device_node *np)
+{
+	unsigned long flags;
+	int rc = 0;
+
+	mutex_lock(&of_mutex);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
+	__of_detach_node(np);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+	mutex_unlock(&of_mutex);
+
+	return rc;
+}
+#endif
+
 static void __init of_selftest_find_node_by_name(void)
 {
 	struct device_node *np;
@@ -86,6 +183,7 @@ static void __init of_selftest_find_node_by_name(void)
 
 static void __init of_selftest_dynamic(void)
 {
+#ifdef CONFIG_OF_DYNAMIC
 	struct device_node *np;
 	struct property *prop;
 
@@ -143,6 +241,7 @@ static void __init of_selftest_dynamic(void)
 	if (prop->value)
 		selftest(of_add_property(np, prop) == 0,
 			 "Adding a large property should have passed\n");
+#endif
 }
 
 static void __init of_selftest_parse_phandle_with_args(void)
@@ -697,7 +796,9 @@ static int __init selftest_data_add(void)
 		of_allnodes = selftest_data_node;
 
 		for_each_of_allnodes(np)
+#ifdef CONFIG_OF_DYNAMIC
 			__of_attach_node_sysfs(np);
+#endif
 		of_aliases = of_find_node_by_path("/aliases");
 		of_chosen = of_find_node_by_path("/chosen");
 		return 0;
@@ -740,7 +841,9 @@ static void selftest_data_remove(void)
 		of_chosen = NULL;
 		for_each_child_of_node(of_allnodes, np)
 			detach_node_and_children(np);
+#ifdef CONFIG_OF_DYNAMIC
 		__of_detach_node_sysfs(of_allnodes);
+#endif
 		of_allnodes = NULL;
 		return;
 	}
-- 
1.7.9.5

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Re: [PATCH] Removes OF_SELFTEST dependency on OF_DYNAMIC

[Grant Likely]

On Mon, 25 Aug 2014 06:43:34 -0700, Gaurav Minocha <gaurav.minocha.os-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> This patch is used to remove the selftests dependency on
> OF_DYNAMIC config flag. Now, it executes only the tests
> that do not depend upon CONFIG_OF_DYNAMIC. Also, it
> defines the functions to attach and detach the node
> if OF_DYNAMIC flag isn't enabled.
> 
> Tested with and without OF_DYNAMIC enabled.

Hi Gaurav,

Thanks for the patch. We've already talked about this on the phone, but
for posterity I've added comments below...

> 
> Signed-off-by: Gaurav Minocha <gaurav.minocha.os-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/of/Kconfig    |    1 -
>  drivers/of/selftest.c |  103 +++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 103 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
> index 5160c4e..1fe3805 100644
> --- a/drivers/of/Kconfig
> +++ b/drivers/of/Kconfig
> @@ -10,7 +10,6 @@ menu "Device Tree and Open Firmware support"
>  config OF_SELFTEST
>  	bool "Device Tree Runtime self tests"
>  	depends on OF_IRQ && OF_EARLY_FLATTREE
> -	select OF_DYNAMIC
>  	help
>  	  This option builds in test cases for the device tree infrastructure
>  	  that are executed once at boot time, and the results dumped to the
> diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c
> index a737cb5..7330007 100644
> --- a/drivers/of/selftest.c
> +++ b/drivers/of/selftest.c
> @@ -39,6 +39,103 @@ static bool selftest_live_tree;
>  	} \
>  }
>  
> +#if !defined(CONFIG_OF_DYNAMIC)
> +void __of_attach_node(struct device_node *np)
> +{
> +	const __be32 *phandle;
> +	int sz;
> +
> +	np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
> +	np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
> +	phandle = __of_get_property(np, "phandle", &sz);
> +	if (!phandle)
> +		phandle = __of_get_property(np, "linux,phandle", &sz);
> +	if (IS_ENABLED(PPC_PSERIES) && !phandle)
> +		phandle = __of_get_property(np, "ibm,phandle", &sz);

The above two lines can be dropped. The test data doesn't use the
ibm,phandle property. Only IBM firmware does.

> +	np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;
> +	np->sibling = np->parent->child;
> +	np->allnext = np->parent->allnext;
> +	np->parent->allnext = np;
> +	np->parent->child = np;
> +	of_node_clear_flag(np, OF_DETACHED);
> +}
> +
> +/**
> + * of_attach_node() - Plug a device node into the tree and global list.
> + */
> +int of_attach_node(struct device_node *np)
> +{
> +	unsigned long flags;
> +
> +	mutex_lock(&of_mutex);
> +	raw_spin_lock_irqsave(&devtree_lock, flags);
> +	__of_attach_node(np);
> +	raw_spin_unlock_irqrestore(&devtree_lock, flags);
> +	mutex_unlock(&of_mutex);
> +
> +	return 0;
> +}

Given that this is only used by the selftest module, there is no need
for the separate __of_attach_node() function wrapped by of_attach_node().
Just put the body of __of_attach_node into this function.

> +
> +void __of_detach_node(struct device_node *np)
> +{
> +	struct device_node *parent;
> +
> +	if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
> +		return;
> +
> +	parent = np->parent;
> +	if (WARN_ON(!parent))
> +		return;
> +
> +	if (of_allnodes == np)
> +		of_allnodes = np->allnext;
> +	else {
> +		struct device_node *prev;
> +
> +		for (prev = of_allnodes;
> +		     prev->allnext != np;
> +		     prev = prev->allnext)
> +			;
> +		prev->allnext = np->allnext;
> +	}
> +
> +	if (parent->child == np)
> +		parent->child = np->sibling;
> +	else {
> +		struct device_node *prevsib;
> +
> +		for (prevsib = np->parent->child;
> +		     prevsib->sibling != np;
> +		     prevsib = prevsib->sibling)
> +			;
> +		prevsib->sibling = np->sibling;
> +	}
> +
> +	of_node_set_flag(np, OF_DETACHED);
> +}
> +
> +/**
> + * of_detach_node() - "Unplug" a node from the device tree.
> + *
> + * The caller must hold a reference to the node.  The memory associated with
> + * the node is not freed until its refcount goes to zero.
> + */
> +int of_detach_node(struct device_node *np)
> +{
> +	unsigned long flags;
> +	int rc = 0;
> +
> +	mutex_lock(&of_mutex);
> +	raw_spin_lock_irqsave(&devtree_lock, flags);
> +	__of_detach_node(np);
> +	raw_spin_unlock_irqrestore(&devtree_lock, flags);
> +
> +	mutex_unlock(&of_mutex);
> +
> +	return rc;
> +}
> +#endif
> +
>  static void __init of_selftest_find_node_by_name(void)
>  {
>  	struct device_node *np;
> @@ -86,6 +183,7 @@ static void __init of_selftest_find_node_by_name(void)
>  
>  static void __init of_selftest_dynamic(void)
>  {
> +#ifdef CONFIG_OF_DYNAMIC
>  	struct device_node *np;
>  	struct property *prop;
>  
> @@ -143,6 +241,7 @@ static void __init of_selftest_dynamic(void)
>  	if (prop->value)
>  		selftest(of_add_property(np, prop) == 0,
>  			 "Adding a large property should have passed\n");
> +#endif
>  }
>  
>  static void __init of_selftest_parse_phandle_with_args(void)
> @@ -697,7 +796,9 @@ static int __init selftest_data_add(void)
>  		of_allnodes = selftest_data_node;
>  
>  		for_each_of_allnodes(np)
> +#ifdef CONFIG_OF_DYNAMIC
>  			__of_attach_node_sysfs(np);
> +#endif

The normal way to block out a function call is to define an empty
__of_attach_node_sysfs() static inline so that #ifdefs don't appear in
the middle of a function.

BTW, this hunk is also buggy. When CONFIG_OF_DYNAMIC is disabled it
executes the next line once for each and every node.

However, despite all of the above, I don't think we can get away with
not registering the nodes with sysfs. Doing that means we can't ever
write tests for the sysfs integration.

>  		of_aliases = of_find_node_by_path("/aliases");
>  		of_chosen = of_find_node_by_path("/chosen");
>  		return 0;
> @@ -740,7 +841,9 @@ static void selftest_data_remove(void)
>  		of_chosen = NULL;
>  		for_each_child_of_node(of_allnodes, np)
>  			detach_node_and_children(np);
> +#ifdef CONFIG_OF_DYNAMIC
>  		__of_detach_node_sysfs(of_allnodes);
> +#endif

This must be done otherwise sysfs will be in an inconsistent state.
We've got three choices here. 1) don't bother removing the testcase
data, 2) include the __of_attach_node_sysfs() and __of_detach_node_sysfs()
hooks, or 3) don't attach the nodes to sysfs at all. Not attaching to
sysfs isn't appealing because it means we can't ever write tests that
depend on the sysfs hooks.

Originally, I was thinking that not removing the data is the best
approach, but after looking at it there really isn't much more that
needs to be pulled in to make it work. I would go with option 2 and make
sure the sysfs registrations are properly handled.

g.
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