2014-01-22 06:56:21

by Xiubo Li

Subject: [PATCHv2 1/2] of: add __of_add_property() without lock operations

There two places will use the same code for adding one new property to
the DT node. Adding __of_add_property() and prepare for fixing
of_update_property()'s bug.

Signed-off-by: Xiubo Li <[email protected]>
---
drivers/of/base.c | 38 ++++++++++++++++++++++++--------------
1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index f807d0e..b86b77a 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1469,11 +1469,31 @@ static int of_property_notify(int action, struct device_node *np,
#endif

/**
+ * __of_add_property - Add a property to a node without lock operations
+ */
+static int __of_add_property(struct device_node *np, struct property *prop)
+{
+ struct property **next;
+
+ prop->next = NULL;
+ next = &np->properties;
+ while (*next) {
+ if (strcmp(prop->name, (*next)->name) == 0)
+ /* duplicate ! don't insert it */
+ return -EEXIST;
+
+ next = &(*next)->next;
+ }
+ *next = prop;
+
+ return 0;
+}
+
+/**
* of_add_property - Add a property to a node
*/
int of_add_property(struct device_node *np, struct property *prop)
{
- struct property **next;
unsigned long flags;
int rc;

@@ -1481,27 +1501,17 @@ int of_add_property(struct device_node *np, struct property *prop)
if (rc)
return rc;

- prop->next = NULL;
raw_spin_lock_irqsave(&devtree_lock, flags);
- next = &np->properties;
- while (*next) {
- if (strcmp(prop->name, (*next)->name) == 0) {
- /* duplicate ! don't insert it */
- raw_spin_unlock_irqrestore(&devtree_lock, flags);
- return -1;
- }
- next = &(*next)->next;
- }
- *next = prop;
+ rc = __of_add_property(np, prop);
raw_spin_unlock_irqrestore(&devtree_lock, flags);

#ifdef CONFIG_PROC_DEVICETREE
/* try to add to proc as well if it was initialized */
- if (np->pde)
+ if (!rc && np->pde)
proc_device_tree_add_prop(np->pde, prop);
#endif /* CONFIG_PROC_DEVICETREE */

- return 0;
+ return rc;
}

/**
--
1.8.4

2014-01-22 06:56:30

by Xiubo Li

Subject: [PATCHv2 2/2] of: fix of_update_property()

The of_update_property() is intented to update a property in a node
and if the property does not exist, will add it.

The second search of the property is possibly won't be found, that
maybe removed by other thread just before the second search begain.

Using the __of_find_property() and __of_add_property() instead and
move them into lock operations.

Signed-off-by: Xiubo Li <[email protected]>
Cc: Pantelis Antoniou <[email protected]>
---
drivers/of/base.c | 36 ++++++++++++++----------------------
1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index b86b77a..458072d 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1573,7 +1573,7 @@ int of_update_property(struct device_node *np, struct property *newprop)
{
struct property **next, *oldprop;
unsigned long flags;
- int rc, found = 0;
+ int rc = 0;

rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
if (rc)
@@ -1582,36 +1582,28 @@ int of_update_property(struct device_node *np, struct property *newprop)
if (!newprop->name)
return -EINVAL;

- oldprop = of_find_property(np, newprop->name, NULL);
- if (!oldprop)
- return of_add_property(np, newprop);
-
raw_spin_lock_irqsave(&devtree_lock, flags);
- next = &np->properties;
- while (*next) {
- if (*next == oldprop) {
- /* found the node */
- newprop->next = oldprop->next;
- *next = newprop;
- oldprop->next = np->deadprops;
- np->deadprops = oldprop;
- found = 1;
- break;
- }
- next = &(*next)->next;
+ oldprop = __of_find_property(np, newprop->name, NULL);
+ if (!oldprop) {
+ /* add the node */
+ rc = __of_add_property(np, newprop);
+ } else {
+ /* replace the node */
+ next = &oldprop;
+ newprop->next = oldprop->next;
+ *next = newprop;
+ oldprop->next = np->deadprops;
+ np->deadprops = oldprop;
}
raw_spin_unlock_irqrestore(&devtree_lock, flags);

- if (!found)
- return -ENODEV;
-
#ifdef CONFIG_PROC_DEVICETREE
/* try to add to proc as well if it was initialized */
- if (np->pde)
+ if (!rc && np->pde)
proc_device_tree_update_prop(np->pde, newprop, oldprop);
#endif /* CONFIG_PROC_DEVICETREE */

- return 0;
+ return rc;
}

#if defined(CONFIG_OF_DYNAMIC)
--
1.8.4

2014-02-04 17:22:15

by Grant Likely

Subject: Re: [PATCHv2 1/2] of: add __of_add_property() without lock operations

On Wed, 22 Jan 2014 13:57:39 +0800, Xiubo Li <[email protected]> wrote:
> There two places will use the same code for adding one new property to
> the DT node. Adding __of_add_property() and prepare for fixing
> of_update_property()'s bug.
>
> Signed-off-by: Xiubo Li <[email protected]>

Applied, thanks.

g.

> ---
> drivers/of/base.c | 38 ++++++++++++++++++++++++--------------
> 1 file changed, 24 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index f807d0e..b86b77a 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -1469,11 +1469,31 @@ static int of_property_notify(int action, struct device_node *np,
> #endif
>
> /**
> + * __of_add_property - Add a property to a node without lock operations
> + */
> +static int __of_add_property(struct device_node *np, struct property *prop)
> +{
> + struct property **next;
> +
> + prop->next = NULL;
> + next = &np->properties;
> + while (*next) {
> + if (strcmp(prop->name, (*next)->name) == 0)
> + /* duplicate ! don't insert it */
> + return -EEXIST;
> +
> + next = &(*next)->next;
> + }
> + *next = prop;
> +
> + return 0;
> +}
> +
> +/**
> * of_add_property - Add a property to a node
> */
> int of_add_property(struct device_node *np, struct property *prop)
> {
> - struct property **next;
> unsigned long flags;
> int rc;
>
> @@ -1481,27 +1501,17 @@ int of_add_property(struct device_node *np, struct property *prop)
> if (rc)
> return rc;
>
> - prop->next = NULL;
> raw_spin_lock_irqsave(&devtree_lock, flags);
> - next = &np->properties;
> - while (*next) {
> - if (strcmp(prop->name, (*next)->name) == 0) {
> - /* duplicate ! don't insert it */
> - raw_spin_unlock_irqrestore(&devtree_lock, flags);
> - return -1;
> - }
> - next = &(*next)->next;
> - }
> - *next = prop;
> + rc = __of_add_property(np, prop);
> raw_spin_unlock_irqrestore(&devtree_lock, flags);
>
> #ifdef CONFIG_PROC_DEVICETREE
> /* try to add to proc as well if it was initialized */
> - if (np->pde)
> + if (!rc && np->pde)
> proc_device_tree_add_prop(np->pde, prop);
> #endif /* CONFIG_PROC_DEVICETREE */
>
> - return 0;
> + return rc;
> }
>
> /**
> --
> 1.8.4
>
>

2014-02-04 17:24:51

by Grant Likely

Subject: Re: [PATCHv2 2/2] of: fix of_update_property()

On Wed, 22 Jan 2014 13:57:40 +0800, Xiubo Li <[email protected]> wrote:
> The of_update_property() is intented to update a property in a node
> and if the property does not exist, will add it.
>
> The second search of the property is possibly won't be found, that
> maybe removed by other thread just before the second search begain.
>
> Using the __of_find_property() and __of_add_property() instead and
> move them into lock operations.
>
> Signed-off-by: Xiubo Li <[email protected]>
> Cc: Pantelis Antoniou <[email protected]>

Applied, thanks

g.

> ---
> drivers/of/base.c | 36 ++++++++++++++----------------------
> 1 file changed, 14 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index b86b77a..458072d 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -1573,7 +1573,7 @@ int of_update_property(struct device_node *np, struct property *newprop)
> {
> struct property **next, *oldprop;
> unsigned long flags;
> - int rc, found = 0;
> + int rc = 0;
>
> rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
> if (rc)
> @@ -1582,36 +1582,28 @@ int of_update_property(struct device_node *np, struct property *newprop)
> if (!newprop->name)
> return -EINVAL;
>
> - oldprop = of_find_property(np, newprop->name, NULL);
> - if (!oldprop)
> - return of_add_property(np, newprop);
> -
> raw_spin_lock_irqsave(&devtree_lock, flags);
> - next = &np->properties;
> - while (*next) {
> - if (*next == oldprop) {
> - /* found the node */
> - newprop->next = oldprop->next;
> - *next = newprop;
> - oldprop->next = np->deadprops;
> - np->deadprops = oldprop;
> - found = 1;
> - break;
> - }
> - next = &(*next)->next;
> + oldprop = __of_find_property(np, newprop->name, NULL);
> + if (!oldprop) {
> + /* add the node */
> + rc = __of_add_property(np, newprop);
> + } else {
> + /* replace the node */
> + next = &oldprop;
> + newprop->next = oldprop->next;
> + *next = newprop;
> + oldprop->next = np->deadprops;
> + np->deadprops = oldprop;
> }
> raw_spin_unlock_irqrestore(&devtree_lock, flags);
>
> - if (!found)
> - return -ENODEV;
> -
> #ifdef CONFIG_PROC_DEVICETREE
> /* try to add to proc as well if it was initialized */
> - if (np->pde)
> + if (!rc && np->pde)
> proc_device_tree_update_prop(np->pde, newprop, oldprop);
> #endif /* CONFIG_PROC_DEVICETREE */
>
> - return 0;
> + return rc;
> }
>
> #if defined(CONFIG_OF_DYNAMIC)
> --
> 1.8.4
>
>