On 01/25/2013 12:21 PM, Paul Gortmaker wrote:
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>
> There is no real reason to use a rwlock for devtree_lock. It even
> could be a mutex, but unfortunately it's locked from cpu hotplug
> paths which can't schedule :(
>
> So it needs to become a raw lock on rt as well. The devtree_lock would
> be the only user of a raw_rw_lock, so we are better off cleaning up the
> recursive locking paths which allows us to convert devtree_lock to a
> read_lock.
>
> Here we do the standard thing of introducing __foo() as the "raw"
> version of foo(), so that we can take better control of the locking.
> The "raw" versions are not exported and are for internal use within
> the file itself.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
> ---
Applied for 3.9.
Rob
>
> [This has been living in the RT tree for several releases, and I've
> put it on top of 3.8-rc4 mainline and tested it independently there
> on a ppc sbc8548 board as well. So it would be nice to get this in 3.9]
>
> drivers/of/base.c | 91 ++++++++++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 70 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 2390ddb..21195a1 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -164,16 +164,14 @@ void of_node_put(struct device_node *node)
> EXPORT_SYMBOL(of_node_put);
> #endif /* CONFIG_OF_DYNAMIC */
>
> -struct property *of_find_property(const struct device_node *np,
> - const char *name,
> - int *lenp)
> +static struct property *__of_find_property(const struct device_node *np,
> + const char *name, int *lenp)
> {
> struct property *pp;
>
> if (!np)
> return NULL;
>
> - read_lock(&devtree_lock);
> for (pp = np->properties; pp; pp = pp->next) {
> if (of_prop_cmp(pp->name, name) == 0) {
> if (lenp)
> @@ -181,6 +179,18 @@ struct property *of_find_property(const struct device_node *np,
> break;
> }
> }
> +
> + return pp;
> +}
> +
> +struct property *of_find_property(const struct device_node *np,
> + const char *name,
> + int *lenp)
> +{
> + struct property *pp;
> +
> + read_lock(&devtree_lock);
> + pp = __of_find_property(np, name, lenp);
> read_unlock(&devtree_lock);
>
> return pp;
> @@ -214,8 +224,20 @@ EXPORT_SYMBOL(of_find_all_nodes);
> * Find a property with a given name for a given node
> * and return the value.
> */
> +static const void *__of_get_property(const struct device_node *np,
> + const char *name, int *lenp)
> +{
> + struct property *pp = __of_find_property(np, name, lenp);
> +
> + return pp ? pp->value : NULL;
> +}
> +
> +/*
> + * Find a property with a given name for a given node
> + * and return the value.
> + */
> const void *of_get_property(const struct device_node *np, const char *name,
> - int *lenp)
> + int *lenp)
> {
> struct property *pp = of_find_property(np, name, lenp);
>
> @@ -226,13 +248,13 @@ EXPORT_SYMBOL(of_get_property);
> /** Checks if the given "compat" string matches one of the strings in
> * the device's "compatible" property
> */
> -int of_device_is_compatible(const struct device_node *device,
> - const char *compat)
> +static int __of_device_is_compatible(const struct device_node *device,
> + const char *compat)
> {
> const char* cp;
> int cplen, l;
>
> - cp = of_get_property(device, "compatible", &cplen);
> + cp = __of_get_property(device, "compatible", &cplen);
> if (cp == NULL)
> return 0;
> while (cplen > 0) {
> @@ -245,6 +267,20 @@ int of_device_is_compatible(const struct device_node *device,
>
> return 0;
> }
> +
> +/** Checks if the given "compat" string matches one of the strings in
> + * the device's "compatible" property
> + */
> +int of_device_is_compatible(const struct device_node *device,
> + const char *compat)
> +{
> + int res;
> +
> + read_lock(&devtree_lock);
> + res = __of_device_is_compatible(device, compat);
> + read_unlock(&devtree_lock);
> + return res;
> +}
> EXPORT_SYMBOL(of_device_is_compatible);
>
> /**
> @@ -518,7 +554,8 @@ struct device_node *of_find_compatible_node(struct device_node *from,
> if (type
> && !(np->type && (of_node_cmp(np->type, type) == 0)))
> continue;
> - if (of_device_is_compatible(np, compatible) && of_node_get(np))
> + if (__of_device_is_compatible(np, compatible) &&
> + of_node_get(np))
> break;
> }
> of_node_put(from);
> @@ -562,15 +599,9 @@ out:
> }
> EXPORT_SYMBOL(of_find_node_with_property);
>
> -/**
> - * of_match_node - Tell if an device_node has a matching of_match structure
> - * @matches: array of of device match structures to search in
> - * @node: the of device structure to match against
> - *
> - * Low level utility function used by device matching.
> - */
> -const struct of_device_id *of_match_node(const struct of_device_id *matches,
> - const struct device_node *node)
> +static
> +const struct of_device_id *__of_match_node(const struct of_device_id *matches,
> + const struct device_node *node)
> {
> if (!matches)
> return NULL;
> @@ -584,14 +615,32 @@ const struct of_device_id *of_match_node(const struct of_device_id *matches,
> match &= node->type
> && !strcmp(matches->type, node->type);
> if (matches->compatible[0])
> - match &= of_device_is_compatible(node,
> - matches->compatible);
> + match &= __of_device_is_compatible(node,
> + matches->compatible);
> if (match)
> return matches;
> matches++;
> }
> return NULL;
> }
> +
> +/**
> + * of_match_node - Tell if an device_node has a matching of_match structure
> + * @matches: array of of device match structures to search in
> + * @node: the of device structure to match against
> + *
> + * Low level utility function used by device matching.
> + */
> +const struct of_device_id *of_match_node(const struct of_device_id *matches,
> + const struct device_node *node)
> +{
> + const struct of_device_id *match;
> +
> + read_lock(&devtree_lock);
> + match = __of_match_node(matches, node);
> + read_unlock(&devtree_lock);
> + return match;
> +}
> EXPORT_SYMBOL(of_match_node);
>
> /**
> @@ -619,7 +668,7 @@ struct device_node *of_find_matching_node_and_match(struct device_node *from,
> read_lock(&devtree_lock);
> np = from ? from->allnext : of_allnodes;
> for (; np; np = np->allnext) {
> - if (of_match_node(matches, np) && of_node_get(np)) {
> + if (__of_match_node(matches, np) && of_node_get(np)) {
> if (match)
> *match = matches;
> break;
>
--
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