[PATCH v2 3/4] resource: Add device-managed insert/remove_resource()

Toshi Kani
2016-03-02T21:58:24Z

insert_resource() and remove_resouce() are called by producers
of resources, such as FW modules and bus drivers. These modules
may be implemented as loadable modules.

Add device-managed implementaions of insert_resource() and
remove_resouce() functions.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
---
include/linux/ioport.h | 5 +++
kernel/resource.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 74 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 8017b8b..3580038 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -259,6 +259,11 @@ extern struct resource * __devm_request_region(struct device *dev,

extern void __devm_release_region(struct device *dev, struct resource *parent,
resource_size_t start, resource_size_t n);
+
+extern int devm_insert_resource(struct device *dev, struct resource *root,
+ struct resource *new);
+extern void devm_remove_resource(struct device *dev, struct resource *old);
+
extern int iomem_map_sanity_check(resource_size_t addr, unsigned long size);
extern int iomem_is_exclusive(u64 addr);

diff --git a/kernel/resource.c b/kernel/resource.c
index effb6ee..b1a3394 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1449,6 +1449,75 @@ void __devm_release_region(struct device *dev, struct resource *parent,
EXPORT_SYMBOL(__devm_release_region);

/*
+ * Remove function for devm_insert_resource() and devm_remove_resource().
+ */
+static void devm_resource_remove(struct device *dev, void *ptr)
+{
+ struct resource **r = ptr;
+
+ remove_resource(*r);
+}
+
+/**
+ * devm_insert_resource() - insert an I/O or memory resource
+ * @dev: device for which to produce the resource
+ * @root: root of the resource tree
+ * @new: descriptor of the new resource
+ *
+ * This is a device-managed version of insert_resource(). There is usually
+ * no need to release resources requested by this function explicitly since
+ * that will be taken care of when the device is unbound from its bus driver.
+ * If for some reason the resource needs to be released explicitly, because
+ * of ordering issues for example, bus drivers must call devm_remove_resource()
+ * rather than the regular remove_resource().
+ *
+ * devm_insert_resource() is intended for producers of resources, such as
+ * FW modules and bus drivers.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int devm_insert_resource(struct device *dev, struct resource *root,
+ struct resource *new)
+{
+ struct resource **ptr;
+ int ret;
+
+ ptr = devres_alloc(devm_resource_remove, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return -ENOMEM;
+
+ *ptr = new;
+
+ ret = insert_resource(root, new);
+ if (ret) {
+ dev_err(dev, "unable to insert resource: %pR (%d)\n", new, ret);
+ devres_free(ptr);
+ return -EBUSY;
+ }
+
+ devres_add(dev, ptr);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(devm_insert_resource);
+
+/**
+ * devm_remove_resource() - remove a previously inserted resource
+ * @dev: device for which to remove the resource
+ * @old: descriptor of the resource
+ *
+ * Remove a resource previously inserted using devm_insert_resource().
+ *
+ * devm_remove_resource() is intended for producers of resources, such as
+ * FW modules and bus drivers.
+ */
+void devm_remove_resource(struct device *dev, struct resource *old)
+{
+ WARN_ON(devres_release(dev, devm_resource_remove, devm_resource_match,
+ old));
+}
+EXPORT_SYMBOL_GPL(devm_remove_resource);
+
+/*
* Called from init/main.c to reserve IO ports.
*/
#define MAXRESERVE 4