// 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>
 */

#include <kunit/resource.h>
#include <kunit/test.h>
#include <linux/kref.h>

/*
 * Used for static resources and when a kunit_resource * has been created by
 * kunit_alloc_resource().  When an init function is supplied, @data is passed
 * into the init function; otherwise, we simply set the resource data field to
 * the data value passed in. Doesn't initialize res->should_kfree.
 */
int __kunit_add_resource(struct kunit *test,
                         kunit_resource_init_t init,
                         kunit_resource_free_t free,
                         struct kunit_resource *res,
                         void *data)
{
        int ret = 0;
        unsigned long flags;

        res->free = free;
        kref_init(&res->refcount);

        if (init) {
                ret = init(res, data);
                if (ret)
                        return ret;
        } else {
                res->data = data;
        }

        spin_lock_irqsave(&test->lock, flags);
        list_add_tail(&res->node, &test->resources);
        /* refcount for list is established by kref_init() */
        spin_unlock_irqrestore(&test->lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(__kunit_add_resource);

void kunit_remove_resource(struct kunit *test, struct kunit_resource *res)
{
        unsigned long flags;
        bool was_linked;

        spin_lock_irqsave(&test->lock, flags);
        was_linked = !list_empty(&res->node);
        list_del_init(&res->node);
        spin_unlock_irqrestore(&test->lock, flags);

        if (was_linked)
                kunit_put_resource(res);
}
EXPORT_SYMBOL_GPL(kunit_remove_resource);

int kunit_destroy_resource(struct kunit *test, kunit_resource_match_t match,
                           void *match_data)
{
        struct kunit_resource *res = kunit_find_resource(test, match,
                                                         match_data);

        if (!res)
                return -ENOENT;

        kunit_remove_resource(test, res);

        /* We have a reference also via _find(); drop it. */
        kunit_put_resource(res);

        return 0;
}
EXPORT_SYMBOL_GPL(kunit_destroy_resource);

struct kunit_action_ctx {
        struct kunit_resource res;
        kunit_action_t *func;
        void *ctx;
};

static void __kunit_action_free(struct kunit_resource *res)
{
        struct kunit_action_ctx *action_ctx = container_of(res, struct kunit_action_ctx, res);

        action_ctx->func(action_ctx->ctx);
}


int kunit_add_action(struct kunit *test, void (*action)(void *), void *ctx)
{
        struct kunit_action_ctx *action_ctx;

        KUNIT_ASSERT_NOT_NULL_MSG(test, action, "Tried to action a NULL function!");

        action_ctx = kzalloc_obj(*action_ctx);
        if (!action_ctx)
                return -ENOMEM;

        action_ctx->func = action;
        action_ctx->ctx = ctx;

        action_ctx->res.should_kfree = true;
        /* As init is NULL, this cannot fail. */
        __kunit_add_resource(test, NULL, __kunit_action_free, &action_ctx->res, action_ctx);

        return 0;
}
EXPORT_SYMBOL_GPL(kunit_add_action);

int kunit_add_action_or_reset(struct kunit *test, void (*action)(void *),
                              void *ctx)
{
        int res = kunit_add_action(test, action, ctx);

        if (res)
                action(ctx);
        return res;
}
EXPORT_SYMBOL_GPL(kunit_add_action_or_reset);

static bool __kunit_action_match(struct kunit *test,
                                struct kunit_resource *res, void *match_data)
{
        struct kunit_action_ctx *match_ctx = (struct kunit_action_ctx *)match_data;
        struct kunit_action_ctx *res_ctx = container_of(res, struct kunit_action_ctx, res);

        /* Make sure this is a free function. */
        if (res->free != __kunit_action_free)
                return false;

        /* Both the function and context data should match. */
        return (match_ctx->func == res_ctx->func) && (match_ctx->ctx == res_ctx->ctx);
}

void kunit_remove_action(struct kunit *test,
                        kunit_action_t *action,
                        void *ctx)
{
        struct kunit_action_ctx match_ctx;
        struct kunit_resource *res;

        match_ctx.func = action;
        match_ctx.ctx = ctx;

        res = kunit_find_resource(test, __kunit_action_match, &match_ctx);
        if (res) {
                /* Remove the free function so we don't run the action. */
                res->free = NULL;
                kunit_remove_resource(test, res);
                kunit_put_resource(res);
        }
}
EXPORT_SYMBOL_GPL(kunit_remove_action);

void kunit_release_action(struct kunit *test,
                         kunit_action_t *action,
                         void *ctx)
{
        struct kunit_action_ctx match_ctx;
        struct kunit_resource *res;

        match_ctx.func = action;
        match_ctx.ctx = ctx;

        res = kunit_find_resource(test, __kunit_action_match, &match_ctx);
        if (res) {
                kunit_remove_resource(test, res);
                /* We have to put() this here, else free won't be called. */
                kunit_put_resource(res);
        }
}
EXPORT_SYMBOL_GPL(kunit_release_action);