Add a function to find an existing resource by a resource start address. This allows to implement simple allocators (with a malloc/free-alike API) on top of the resource system.
Signed-off-by: Geert Uytterhoeven <[email protected]> --- include/linux/ioport.h | 1 + kernel/resource.c | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+), 0 deletions(-) diff --git a/include/linux/ioport.h b/include/linux/ioport.h index e9bb22c..63eb429 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -132,6 +132,7 @@ extern int allocate_resource(struct resource *root, struct resource *new, resource_size_t, resource_size_t), void *alignf_data); +struct resource *lookup_resource(struct resource *root, resource_size_t start); int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size); resource_size_t resource_alignment(struct resource *res); diff --git a/kernel/resource.c b/kernel/resource.c index 798e2fa..8d0b479 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -473,6 +473,27 @@ int allocate_resource(struct resource *root, struct resource *new, EXPORT_SYMBOL(allocate_resource); +/** + * lookup_resource - find an existing resource by a resource start address + * @root: root resource descriptor + * @start: resource start address + * + * Returns a pointer to the resource if found, NULL otherwise + */ +struct resource *lookup_resource(struct resource *root, resource_size_t start) +{ + struct resource *res; + + read_lock(&resource_lock); + for (res = root->child; res; res = res->sibling) { + if (res->start == start) + break; + } + read_unlock(&resource_lock); + + return res; +} + /* * Insert a resource into the resource tree. If successful, return NULL, * otherwise return the conflicting resource (compare to __request_resource()) -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-m68k" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
