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![Daniel Latypov](/assets/img/avatar_default.png)
kunit_kfree() exists to clean up allocations from kunit_kmalloc() and friends early instead of waiting for this to happen automatically at the end of the test. But it can be used on *anything* registered with the kunit resource API. E.g. the last 2 statements are equivalent: struct kunit_resource *res = something(); kfree(res->data); kunit_put_resource(res); The problem is that there could be multiple resources that point to the same `data`. E.g. you can have a named resource acting as a pseudo-global variable in a test. If you point it to data allocated with kunit_kmalloc(), then calling `kunit_kfree(ptr)` has the chance to delete either the named resource or to kfree `ptr`. Which one it does depends on the order the resources are registered as kunit_kfree() will delete resources in LIFO order. So this patch restricts kunit_kfree() to only working on resources created by kunit_kmalloc(). Calling it is therefore guaranteed to free the memory, not do anything else. Note: kunit_resource_instance_match() wasn't used outside of KUnit, so it should be safe to remove from the public interface. It's also generally dangerous, as shown above, and shouldn't be used. Signed-off-by: Daniel Latypov <dlatypov@google.com> Reviewed-by: David Gow <davidgow@google.com> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
390 lines
12 KiB
C
390 lines
12 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* KUnit resource API for test managed resources (allocations, etc.).
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*
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* Copyright (C) 2022, Google LLC.
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* Author: Daniel Latypov <dlatypov@google.com>
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*/
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#ifndef _KUNIT_RESOURCE_H
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#define _KUNIT_RESOURCE_H
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#include <kunit/test.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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struct kunit_resource;
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typedef int (*kunit_resource_init_t)(struct kunit_resource *, void *);
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typedef void (*kunit_resource_free_t)(struct kunit_resource *);
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/**
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* struct kunit_resource - represents a *test managed resource*
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* @data: for the user to store arbitrary data.
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* @name: optional name
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* @free: a user supplied function to free the resource.
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*
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* Represents a *test managed resource*, a resource which will automatically be
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* cleaned up at the end of a test case. This cleanup is performed by the 'free'
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* function. The struct kunit_resource itself is freed automatically with
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* kfree() if it was allocated by KUnit (e.g., by kunit_alloc_resource()), but
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* must be freed by the user otherwise.
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*
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* Resources are reference counted so if a resource is retrieved via
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* kunit_alloc_and_get_resource() or kunit_find_resource(), we need
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* to call kunit_put_resource() to reduce the resource reference count
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* when finished with it. Note that kunit_alloc_resource() does not require a
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* kunit_resource_put() because it does not retrieve the resource itself.
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*
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* Example:
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*
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* .. code-block:: c
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*
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* struct kunit_kmalloc_params {
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* size_t size;
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* gfp_t gfp;
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* };
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*
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* static int kunit_kmalloc_init(struct kunit_resource *res, void *context)
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* {
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* struct kunit_kmalloc_params *params = context;
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* res->data = kmalloc(params->size, params->gfp);
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*
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* if (!res->data)
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* return -ENOMEM;
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*
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* return 0;
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* }
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*
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* static void kunit_kmalloc_free(struct kunit_resource *res)
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* {
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* kfree(res->data);
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* }
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*
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* void *kunit_kmalloc(struct kunit *test, size_t size, gfp_t gfp)
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* {
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* struct kunit_kmalloc_params params;
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*
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* params.size = size;
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* params.gfp = gfp;
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*
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* return kunit_alloc_resource(test, kunit_kmalloc_init,
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* kunit_kmalloc_free, ¶ms);
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* }
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*
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* Resources can also be named, with lookup/removal done on a name
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* basis also. kunit_add_named_resource(), kunit_find_named_resource()
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* and kunit_destroy_named_resource(). Resource names must be
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* unique within the test instance.
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*/
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struct kunit_resource {
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void *data;
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const char *name;
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kunit_resource_free_t free;
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/* private: internal use only. */
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struct kref refcount;
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struct list_head node;
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bool should_kfree;
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};
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/**
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* kunit_get_resource() - Hold resource for use. Should not need to be used
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* by most users as we automatically get resources
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* retrieved by kunit_find_resource*().
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* @res: resource
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*/
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static inline void kunit_get_resource(struct kunit_resource *res)
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{
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kref_get(&res->refcount);
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}
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/*
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* Called when refcount reaches zero via kunit_put_resource();
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* should not be called directly.
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*/
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static inline void kunit_release_resource(struct kref *kref)
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{
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struct kunit_resource *res = container_of(kref, struct kunit_resource,
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refcount);
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if (res->free)
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res->free(res);
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/* 'res' is valid here, as if should_kfree is set, res->free may not free
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* 'res' itself, just res->data
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*/
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if (res->should_kfree)
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kfree(res);
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}
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/**
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* kunit_put_resource() - When caller is done with retrieved resource,
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* kunit_put_resource() should be called to drop
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* reference count. The resource list maintains
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* a reference count on resources, so if no users
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* are utilizing a resource and it is removed from
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* the resource list, it will be freed via the
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* associated free function (if any). Only
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* needs to be used if we alloc_and_get() or
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* find() resource.
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* @res: resource
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*/
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static inline void kunit_put_resource(struct kunit_resource *res)
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{
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kref_put(&res->refcount, kunit_release_resource);
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}
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/**
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* __kunit_add_resource() - Internal helper to add a resource.
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*
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* res->should_kfree is not initialised.
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* @test: The test context object.
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* @init: a user-supplied function to initialize the result (if needed). If
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* none is supplied, the resource data value is simply set to @data.
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* If an init function is supplied, @data is passed to it instead.
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* @free: a user-supplied function to free the resource (if needed).
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* @res: The resource.
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* @data: value to pass to init function or set in resource data field.
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*/
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int __kunit_add_resource(struct kunit *test,
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kunit_resource_init_t init,
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kunit_resource_free_t free,
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struct kunit_resource *res,
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void *data);
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/**
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* kunit_add_resource() - Add a *test managed resource*.
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* @test: The test context object.
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* @init: a user-supplied function to initialize the result (if needed). If
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* none is supplied, the resource data value is simply set to @data.
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* If an init function is supplied, @data is passed to it instead.
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* @free: a user-supplied function to free the resource (if needed).
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* @res: The resource.
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* @data: value to pass to init function or set in resource data field.
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*/
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static inline int kunit_add_resource(struct kunit *test,
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kunit_resource_init_t init,
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kunit_resource_free_t free,
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struct kunit_resource *res,
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void *data)
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{
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res->should_kfree = false;
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return __kunit_add_resource(test, init, free, res, data);
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}
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static inline struct kunit_resource *
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kunit_find_named_resource(struct kunit *test, const char *name);
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/**
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* kunit_add_named_resource() - Add a named *test managed resource*.
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* @test: The test context object.
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* @init: a user-supplied function to initialize the resource data, if needed.
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* @free: a user-supplied function to free the resource data, if needed.
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* @res: The resource.
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* @name: name to be set for resource.
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* @data: value to pass to init function or set in resource data field.
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*/
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static inline int kunit_add_named_resource(struct kunit *test,
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kunit_resource_init_t init,
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kunit_resource_free_t free,
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struct kunit_resource *res,
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const char *name,
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void *data)
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{
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struct kunit_resource *existing;
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if (!name)
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return -EINVAL;
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existing = kunit_find_named_resource(test, name);
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if (existing) {
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kunit_put_resource(existing);
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return -EEXIST;
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}
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res->name = name;
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res->should_kfree = false;
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return __kunit_add_resource(test, init, free, res, data);
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}
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/**
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* kunit_alloc_and_get_resource() - Allocates and returns a *test managed resource*.
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* @test: The test context object.
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* @init: a user supplied function to initialize the resource.
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* @free: a user supplied function to free the resource (if needed).
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* @internal_gfp: gfp to use for internal allocations, if unsure, use GFP_KERNEL
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* @context: for the user to pass in arbitrary data to the init function.
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*
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* Allocates a *test managed resource*, a resource which will automatically be
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* cleaned up at the end of a test case. See &struct kunit_resource for an
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* example.
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*
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* This is effectively identical to kunit_alloc_resource, but returns the
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* struct kunit_resource pointer, not just the 'data' pointer. It therefore
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* also increments the resource's refcount, so kunit_put_resource() should be
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* called when you've finished with it.
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*
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* Note: KUnit needs to allocate memory for a kunit_resource object. You must
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* specify an @internal_gfp that is compatible with the use context of your
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* resource.
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*/
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static inline struct kunit_resource *
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kunit_alloc_and_get_resource(struct kunit *test,
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kunit_resource_init_t init,
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kunit_resource_free_t free,
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gfp_t internal_gfp,
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void *context)
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{
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struct kunit_resource *res;
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int ret;
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res = kzalloc(sizeof(*res), internal_gfp);
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if (!res)
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return NULL;
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res->should_kfree = true;
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ret = __kunit_add_resource(test, init, free, res, context);
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if (!ret) {
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/*
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* bump refcount for get; kunit_resource_put() should be called
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* when done.
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*/
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kunit_get_resource(res);
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return res;
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}
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return NULL;
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}
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/**
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* kunit_alloc_resource() - Allocates a *test managed resource*.
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* @test: The test context object.
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* @init: a user supplied function to initialize the resource.
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* @free: a user supplied function to free the resource (if needed).
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* @internal_gfp: gfp to use for internal allocations, if unsure, use GFP_KERNEL
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* @context: for the user to pass in arbitrary data to the init function.
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*
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* Allocates a *test managed resource*, a resource which will automatically be
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* cleaned up at the end of a test case. See &struct kunit_resource for an
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* example.
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*
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* Note: KUnit needs to allocate memory for a kunit_resource object. You must
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* specify an @internal_gfp that is compatible with the use context of your
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* resource.
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*/
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static inline void *kunit_alloc_resource(struct kunit *test,
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kunit_resource_init_t init,
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kunit_resource_free_t free,
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gfp_t internal_gfp,
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void *context)
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{
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struct kunit_resource *res;
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res = kzalloc(sizeof(*res), internal_gfp);
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if (!res)
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return NULL;
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res->should_kfree = true;
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if (!__kunit_add_resource(test, init, free, res, context))
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return res->data;
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return NULL;
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}
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typedef bool (*kunit_resource_match_t)(struct kunit *test,
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struct kunit_resource *res,
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void *match_data);
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/**
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* kunit_resource_name_match() - Match a resource with the same name.
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* @test: Test case to which the resource belongs.
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* @res: The resource.
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* @match_name: The name to match against.
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*/
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static inline bool kunit_resource_name_match(struct kunit *test,
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struct kunit_resource *res,
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void *match_name)
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{
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return res->name && strcmp(res->name, match_name) == 0;
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}
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/**
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* kunit_find_resource() - Find a resource using match function/data.
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* @test: Test case to which the resource belongs.
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* @match: match function to be applied to resources/match data.
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* @match_data: data to be used in matching.
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*/
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static inline struct kunit_resource *
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kunit_find_resource(struct kunit *test,
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kunit_resource_match_t match,
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void *match_data)
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{
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struct kunit_resource *res, *found = NULL;
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unsigned long flags;
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spin_lock_irqsave(&test->lock, flags);
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list_for_each_entry_reverse(res, &test->resources, node) {
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if (match(test, res, (void *)match_data)) {
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found = res;
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kunit_get_resource(found);
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break;
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}
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}
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spin_unlock_irqrestore(&test->lock, flags);
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return found;
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}
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/**
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* kunit_find_named_resource() - Find a resource using match name.
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* @test: Test case to which the resource belongs.
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* @name: match name.
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*/
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static inline struct kunit_resource *
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kunit_find_named_resource(struct kunit *test,
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const char *name)
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{
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return kunit_find_resource(test, kunit_resource_name_match,
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(void *)name);
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}
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/**
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* kunit_destroy_resource() - Find a kunit_resource and destroy it.
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* @test: Test case to which the resource belongs.
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* @match: Match function. Returns whether a given resource matches @match_data.
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* @match_data: Data passed into @match.
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*
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* RETURNS:
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* 0 if kunit_resource is found and freed, -ENOENT if not found.
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*/
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int kunit_destroy_resource(struct kunit *test,
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kunit_resource_match_t match,
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void *match_data);
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static inline int kunit_destroy_named_resource(struct kunit *test,
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const char *name)
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{
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return kunit_destroy_resource(test, kunit_resource_name_match,
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(void *)name);
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}
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/**
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* kunit_remove_resource() - remove resource from resource list associated with
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* test.
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* @test: The test context object.
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* @res: The resource to be removed.
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*
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* Note that the resource will not be immediately freed since it is likely
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* the caller has a reference to it via alloc_and_get() or find();
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* in this case a final call to kunit_put_resource() is required.
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*/
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void kunit_remove_resource(struct kunit *test, struct kunit_resource *res);
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#endif /* _KUNIT_RESOURCE_H */
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