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/* SPDX-License-Identifier: GPL-2.0 */
/*
* KUnit resource API for test managed resources (allocations, etc.).
*
* Copyright (C) 2022, Google LLC.
* Author: Daniel Latypov <dlatypov@google.com>
*/
#ifndef _KUNIT_RESOURCE_H
#define _KUNIT_RESOURCE_H
#include <kunit/test.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
struct kunit_resource;
typedef int (*kunit_resource_init_t)(struct kunit_resource *, void *);
typedef void (*kunit_resource_free_t)(struct kunit_resource *);
/**
* struct kunit_resource - represents a *test managed resource*
* @data: for the user to store arbitrary data.
* @name: optional name
* @free: a user supplied function to free the resource.
*
* Represents a *test managed resource*, a resource which will automatically be
* cleaned up at the end of a test case. This cleanup is performed by the 'free'
* function. The struct kunit_resource itself is freed automatically with
* kfree() if it was allocated by KUnit (e.g., by kunit_alloc_resource()), but
* must be freed by the user otherwise.
*
* Resources are reference counted so if a resource is retrieved via
* kunit_alloc_and_get_resource() or kunit_find_resource(), we need
* to call kunit_put_resource() to reduce the resource reference count
* when finished with it. Note that kunit_alloc_resource() does not require a
* kunit_resource_put() because it does not retrieve the resource itself.
*
* Example:
*
* .. code-block:: c
*
* struct kunit_kmalloc_params {
* size_t size;
* gfp_t gfp;
* };
*
* static int kunit_kmalloc_init(struct kunit_resource *res, void *context)
* {
* struct kunit_kmalloc_params *params = context;
* res->data = kmalloc(params->size, params->gfp);
*
* if (!res->data)
* return -ENOMEM;
*
* return 0;
* }
*
* static void kunit_kmalloc_free(struct kunit_resource *res)
* {
* kfree(res->data);
* }
*
* void *kunit_kmalloc(struct kunit *test, size_t size, gfp_t gfp)
* {
* struct kunit_kmalloc_params params;
*
* params.size = size;
* params.gfp = gfp;
*
* return kunit_alloc_resource(test, kunit_kmalloc_init,
* kunit_kmalloc_free, gfp, ¶ms);
* }
*
* Resources can also be named, with lookup/removal done on a name
* basis also. kunit_add_named_resource(), kunit_find_named_resource()
* and kunit_destroy_named_resource(). Resource names must be
* unique within the test instance.
*/
struct kunit_resource {
void *data;
const char *name;
kunit_resource_free_t free;
/* private: internal use only. */
struct kref refcount;
struct list_head node;
bool should_kfree;
};
/**
* kunit_get_resource() - Hold resource for use. Should not need to be used
* by most users as we automatically get resources
* retrieved by kunit_find_resource*().
* @res: resource
*/
static inline void kunit_get_resource(struct kunit_resource *res)
{
kref_get(&res->refcount);
}
/*
* Called when refcount reaches zero via kunit_put_resource();
* should not be called directly.
*/
static inline void kunit_release_resource(struct kref *kref)
{
struct kunit_resource *res = container_of(kref, struct kunit_resource,
refcount);
if (res->free)
res->free(res);
/* 'res' is valid here, as if should_kfree is set, res->free may not free
* 'res' itself, just res->data
*/
if (res->should_kfree)
kfree(res);
}
/**
* kunit_put_resource() - When caller is done with retrieved resource,
* kunit_put_resource() should be called to drop
* reference count. The resource list maintains
* a reference count on resources, so if no users
* are utilizing a resource and it is removed from
* the resource list, it will be freed via the
* associated free function (if any). Only
* needs to be used if we alloc_and_get() or
* find() resource.
* @res: resource
*/
static inline void kunit_put_resource(struct kunit_resource *res)
{
kref_put(&res->refcount, kunit_release_resource);
}
/**
* __kunit_add_resource() - Internal helper to add a resource.
*
* res->should_kfree is not initialised.
* @test: The test context object.
* @init: a user-supplied function to initialize the result (if needed). If
* none is supplied, the resource data value is simply set to @data.
* If an init function is supplied, @data is passed to it instead.
* @free: a user-supplied function to free the resource (if needed).
* @res: The resource.
* @data: value to pass to init function or set in resource data field.
*/
int __kunit_add_resource(struct kunit *test,
kunit_resource_init_t init,
kunit_resource_free_t free,
struct kunit_resource *res,
void *data);
/**
* kunit_add_resource() - Add a *test managed resource*.
* @test: The test context object.
* @init: a user-supplied function to initialize the result (if needed). If
* none is supplied, the resource data value is simply set to @data.
* If an init function is supplied, @data is passed to it instead.
* @free: a user-supplied function to free the resource (if needed).
* @res: The resource.
* @data: value to pass to init function or set in resource data field.
*/
static inline int kunit_add_resource(struct kunit *test,
kunit_resource_init_t init,
kunit_resource_free_t free,
struct kunit_resource *res,
void *data)
{
res->should_kfree = false;
return __kunit_add_resource(test, init, free, res, data);
}
static inline struct kunit_resource *
kunit_find_named_resource(struct kunit *test, const char *name);
/**
* kunit_add_named_resource() - Add a named *test managed resource*.
* @test: The test context object.
* @init: a user-supplied function to initialize the resource data, if needed.
* @free: a user-supplied function to free the resource data, if needed.
* @res: The resource.
* @name: name to be set for resource.
* @data: value to pass to init function or set in resource data field.
*/
static inline int kunit_add_named_resource(struct kunit *test,
kunit_resource_init_t init,
kunit_resource_free_t free,
struct kunit_resource *res,
const char *name,
void *data)
{
struct kunit_resource *existing;
if (!name)
return -EINVAL;
existing = kunit_find_named_resource(test, name);
if (existing) {
kunit_put_resource(existing);
return -EEXIST;
}
res->name = name;
res->should_kfree = false;
return __kunit_add_resource(test, init, free, res, data);
}
/**
* kunit_alloc_and_get_resource() - Allocates and returns a *test managed resource*.
* @test: The test context object.
* @init: a user supplied function to initialize the resource.
* @free: a user supplied function to free the resource (if needed).
* @internal_gfp: gfp to use for internal allocations, if unsure, use GFP_KERNEL
* @context: for the user to pass in arbitrary data to the init function.
*
* Allocates a *test managed resource*, a resource which will automatically be
* cleaned up at the end of a test case. See &struct kunit_resource for an
* example.
*
* This is effectively identical to kunit_alloc_resource, but returns the
* struct kunit_resource pointer, not just the 'data' pointer. It therefore
* also increments the resource's refcount, so kunit_put_resource() should be
* called when you've finished with it.
*
* Note: KUnit needs to allocate memory for a kunit_resource object. You must
* specify an @internal_gfp that is compatible with the use context of your
* resource.
*/
static inline struct kunit_resource *
kunit_alloc_and_get_resource(struct kunit *test,
kunit_resource_init_t init,
kunit_resource_free_t free,
gfp_t internal_gfp,
void *context)
{
struct kunit_resource *res;
int ret;
res = kzalloc(sizeof(*res), internal_gfp);
if (!res)
return NULL;
res->should_kfree = true;
ret = __kunit_add_resource(test, init, free, res, context);
if (!ret) {
/*
* bump refcount for get; kunit_resource_put() should be called
* when done.
*/
kunit_get_resource(res);
return res;
}
return NULL;
}
/**
* kunit_alloc_resource() - Allocates a *test managed resource*.
* @test: The test context object.
* @init: a user supplied function to initialize the resource.
* @free: a user supplied function to free the resource (if needed).
* @internal_gfp: gfp to use for internal allocations, if unsure, use GFP_KERNEL
* @context: for the user to pass in arbitrary data to the init function.
*
* Allocates a *test managed resource*, a resource which will automatically be
* cleaned up at the end of a test case. See &struct kunit_resource for an
* example.
*
* Note: KUnit needs to allocate memory for a kunit_resource object. You must
* specify an @internal_gfp that is compatible with the use context of your
* resource.
*/
static inline void *kunit_alloc_resource(struct kunit *test,
kunit_resource_init_t init,
kunit_resource_free_t free,
gfp_t internal_gfp,
void *context)
{
struct kunit_resource *res;
res = kzalloc(sizeof(*res), internal_gfp);
if (!res)
return NULL;
res->should_kfree = true;
if (!__kunit_add_resource(test, init, free, res, context))
return res->data;
return NULL;
}
typedef bool (*kunit_resource_match_t)(struct kunit *test,
struct kunit_resource *res,
void *match_data);
/**
* kunit_resource_name_match() - Match a resource with the same name.
* @test: Test case to which the resource belongs.
* @res: The resource.
* @match_name: The name to match against.
*/
static inline bool kunit_resource_name_match(struct kunit *test,
struct kunit_resource *res,
void *match_name)
{
return res->name && strcmp(res->name, match_name) == 0;
}
/**
* kunit_find_resource() - Find a resource using match function/data.
* @test: Test case to which the resource belongs.
* @match: match function to be applied to resources/match data.
* @match_data: data to be used in matching.
*/
static inline struct kunit_resource *
kunit_find_resource(struct kunit *test,
kunit_resource_match_t match,
void *match_data)
{
struct kunit_resource *res, *found = NULL;
unsigned long flags;
spin_lock_irqsave(&test->lock, flags);
list_for_each_entry_reverse(res, &test->resources, node) {
if (match(test, res, (void *)match_data)) {
found = res;
kunit_get_resource(found);
break;
}
}
spin_unlock_irqrestore(&test->lock, flags);
return found;
}
/**
* kunit_find_named_resource() - Find a resource using match name.
* @test: Test case to which the resource belongs.
* @name: match name.
*/
static inline struct kunit_resource *
kunit_find_named_resource(struct kunit *test,
const char *name)
{
return kunit_find_resource(test, kunit_resource_name_match,
(void *)name);
}
/**
* kunit_destroy_resource() - Find a kunit_resource and destroy it.
* @test: Test case to which the resource belongs.
* @match: Match function. Returns whether a given resource matches @match_data.
* @match_data: Data passed into @match.
*
* RETURNS:
* 0 if kunit_resource is found and freed, -ENOENT if not found.
*/
int kunit_destroy_resource(struct kunit *test,
kunit_resource_match_t match,
void *match_data);
static inline int kunit_destroy_named_resource(struct kunit *test,
const char *name)
{
return kunit_destroy_resource(test, kunit_resource_name_match,
(void *)name);
}
/**
* kunit_remove_resource() - remove resource from resource list associated with
* test.
* @test: The test context object.
* @res: The resource to be removed.
*
* Note that the resource will not be immediately freed since it is likely
* the caller has a reference to it via alloc_and_get() or find();
* in this case a final call to kunit_put_resource() is required.
*/
void kunit_remove_resource(struct kunit *test, struct kunit_resource *res);
/* A 'deferred action' function to be used with kunit_add_action. */
typedef void (kunit_action_t)(void *);
/**
* KUNIT_DEFINE_ACTION_WRAPPER() - Wrap a function for use as a deferred action.
*
* @wrapper: The name of the new wrapper function define.
* @orig: The original function to wrap.
* @arg_type: The type of the argument accepted by @orig.
*
* Defines a wrapper for a function which accepts a single, pointer-sized
* argument. This wrapper can then be passed to kunit_add_action() and
* similar. This should be used in preference to casting a function
* directly to kunit_action_t, as casting function pointers will break
* control flow integrity (CFI), leading to crashes.
*/
#define KUNIT_DEFINE_ACTION_WRAPPER(wrapper, orig, arg_type) \
static void wrapper(void *in) \
{ \
arg_type arg = (arg_type)in; \
orig(arg); \
}
/**
* kunit_add_action() - Call a function when the test ends.
* @test: Test case to associate the action with.
* @action: The function to run on test exit
* @ctx: Data passed into @func
*
* Defer the execution of a function until the test exits, either normally or
* due to a failure. @ctx is passed as additional context. All functions
* registered with kunit_add_action() will execute in the opposite order to that
* they were registered in.
*
* This is useful for cleaning up allocated memory and resources, as these
* functions are called even if the test aborts early due to, e.g., a failed
* assertion.
*
* See also: devm_add_action() for the devres equivalent.
*
* Returns:
* 0 on success, an error if the action could not be deferred.
*/
int kunit_add_action(struct kunit *test, kunit_action_t *action, void *ctx);
/**
* kunit_add_action_or_reset() - Call a function when the test ends.
* @test: Test case to associate the action with.
* @action: The function to run on test exit
* @ctx: Data passed into @func
*
* Defer the execution of a function until the test exits, either normally or
* due to a failure. @ctx is passed as additional context. All functions
* registered with kunit_add_action() will execute in the opposite order to that
* they were registered in.
*
* This is useful for cleaning up allocated memory and resources, as these
* functions are called even if the test aborts early due to, e.g., a failed
* assertion.
*
* If the action cannot be created (e.g., due to the system being out of memory),
* then action(ctx) will be called immediately, and an error will be returned.
*
* See also: devm_add_action_or_reset() for the devres equivalent.
*
* Returns:
* 0 on success, an error if the action could not be deferred.
*/
int kunit_add_action_or_reset(struct kunit *test, kunit_action_t *action,
void *ctx);
/**
* kunit_remove_action() - Cancel a matching deferred action.
* @test: Test case the action is associated with.
* @action: The deferred function to cancel.
* @ctx: The context passed to the deferred function to trigger.
*
* Prevent an action deferred via kunit_add_action() from executing when the
* test terminates.
*
* If the function/context pair was deferred multiple times, only the most
* recent one will be cancelled.
*
* See also: devm_remove_action() for the devres equivalent.
*/
void kunit_remove_action(struct kunit *test,
kunit_action_t *action,
void *ctx);
/**
* kunit_release_action() - Run a matching action call immediately.
* @test: Test case the action is associated with.
* @action: The deferred function to trigger.
* @ctx: The context passed to the deferred function to trigger.
*
* Execute a function deferred via kunit_add_action()) immediately, rather than
* when the test ends.
*
* If the function/context pair was deferred multiple times, it will only be
* executed once here. The most recent deferral will no longer execute when
* the test ends.
*
* kunit_release_action(test, func, ctx);
* is equivalent to
* func(ctx);
* kunit_remove_action(test, func, ctx);
*
* See also: devm_release_action() for the devres equivalent.
*/
void kunit_release_action(struct kunit *test,
kunit_action_t *action,
void *ctx);
#endif /* _KUNIT_RESOURCE_H */