diff options
| author | Geert Uytterhoeven <geert@linux-m68k.org> | 2011-05-07 20:53:16 +0200 |
|---|---|---|
| committer | Geert Uytterhoeven <geert@linux-m68k.org> | 2011-07-30 21:21:39 +0200 |
| commit | 1c388919d89ca35741e9c4d3255adf87f76f0c06 (patch) | |
| tree | 3858d97ce2f91cdf6ec3badafbf66ef058e178a7 | |
| parent | 88efd0bbc0fe403a9948e6f94cc48b9f15ee4861 (diff) | |
resources: Add lookup_resource()
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 <geert@linux-m68k.org>
| -rw-r--r-- | include/linux/ioport.h | 1 | ||||
| -rw-r--r-- | kernel/resource.c | 21 |
2 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/ioport.h b/include/linux/ioport.h index e9bb22cba76..63eb429ecbe 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 3ff40178dce..3b3cedc5259 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -553,6 +553,27 @@ 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()) |