On Fri, Aug 01, 2014 at 02:15:10PM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> Provide device-managed implementations of the request_resource() and
> release_resource() functions. Upon failure to request a resource, the
> new devm_request_resource() function will output an error message for
> consistent error reporting.
>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
Applied both, with Tejun's ack on the first, for v3.18, thanks!
> ---
> Changes in v2:
> - use more natural flow for error handling
> - don't needlessly check for NULL pointers
>
> Documentation/driver-model/devres.txt | 2 +
> include/linux/ioport.h | 5 +++
> kernel/resource.c | 70 +++++++++++++++++++++++++++++++++++
> 3 files changed, 77 insertions(+)
>
> diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
> index d14710b04439..befc3fe12ba6 100644
> --- a/Documentation/driver-model/devres.txt
> +++ b/Documentation/driver-model/devres.txt
> @@ -264,8 +264,10 @@ IIO
> IO region
> devm_release_mem_region()
> devm_release_region()
> + devm_release_resource()
> devm_request_mem_region()
> devm_request_region()
> + devm_request_resource()
>
> IOMAP
> devm_ioport_map()
> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
> index 142ec544167c..2c5250222278 100644
> --- a/include/linux/ioport.h
> +++ b/include/linux/ioport.h
> @@ -215,6 +215,11 @@ static inline int __deprecated check_region(resource_size_t s,
>
> /* Wrappers for managed devices */
> struct device;
> +
> +extern int devm_request_resource(struct device *dev, struct resource *root,
> + struct resource *new);
> +extern void devm_release_resource(struct device *dev, struct resource *new);
> +
> #define devm_request_region(dev,start,n,name) \
> __devm_request_region(dev, &ioport_resource, (start), (n), (name))
> #define devm_request_mem_region(dev,start,n,name) \
> diff --git a/kernel/resource.c b/kernel/resource.c
> index da14b8d09296..ca24f19f9d18 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -1248,6 +1248,76 @@ int release_mem_region_adjustable(struct resource *parent,
> /*
> * Managed region resource
> */
> +static void devm_resource_release(struct device *dev, void *ptr)
> +{
> + struct resource **r = ptr;
> +
> + release_resource(*r);
> +}
> +
> +/**
> + * devm_request_resource() - request and reserve an I/O or memory resource
> + * @dev: device for which to request the resource
> + * @root: root of the resource tree from which to request the resource
> + * @new: descriptor of the resource to request
> + *
> + * This is a device-managed version of request_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 driver.
> + * If for some reason the resource needs to be released explicitly, because
> + * of ordering issues for example, drivers must call devm_release_resource()
> + * rather than the regular release_resource().
> + *
> + * When a conflict is detected between any existing resources and the newly
> + * requested resource, an error message will be printed.
> + *
> + * Returns 0 on success or a negative error code on failure.
> + */
> +int devm_request_resource(struct device *dev, struct resource *root,
> + struct resource *new)
> +{
> + struct resource *conflict, **ptr;
> +
> + ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
> + if (!ptr)
> + return -ENOMEM;
> +
> + *ptr = new;
> +
> + conflict = request_resource_conflict(root, new);
> + if (conflict) {
> + dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
> + new, conflict->name, conflict);
> + devres_free(ptr);
> + return -EBUSY;
> + }
> +
> + devres_add(dev, ptr);
> + return 0;
> +}
> +EXPORT_SYMBOL(devm_request_resource);
> +
> +static int devm_resource_match(struct device *dev, void *res, void *data)
> +{
> + struct resource **ptr = res;
> +
> + return *ptr == data;
> +}
> +
> +/**
> + * devm_release_resource() - release a previously requested resource
> + * @dev: device for which to release the resource
> + * @new: descriptor of the resource to release
> + *
> + * Releases a resource previously requested using devm_request_resource().
> + */
> +void devm_release_resource(struct device *dev, struct resource *new)
> +{
> + WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
> + new));
> +}
> +EXPORT_SYMBOL(devm_release_resource);
> +
> struct region_devres {
> struct resource *parent;
> resource_size_t start;
> --
> 2.0.3
>
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