Create a common API for test managed resources like memory and test
objects. A lot of times a test will want to set up infrastructure to be
used in test cases; this could be anything from just wanting to allocate
some memory to setting up a driver stack; this defines facilities for
creating "test resources" which are managed by the test infrastructure
and are automatically cleaned up at the conclusion of the test.

Signed-off-by: Brendan Higgins <brendanhigg...@google.com>
Reviewed-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Reviewed-by: Logan Gunthorpe <log...@deltatee.com>
Reviewed-by: Stephen Boyd <sb...@kernel.org>
---
 include/kunit/test.h | 187 +++++++++++++++++++++++++++++++++++++++++++
 kunit/test.c         | 163 +++++++++++++++++++++++++++++++++++++
 2 files changed, 350 insertions(+)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index e0b34acb9ee4e..f264ffe58f008 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -9,8 +9,72 @@
 #ifndef _KUNIT_TEST_H
 #define _KUNIT_TEST_H
 
+#include <linux/slab.h>
 #include <linux/types.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*
+ * @allocation: for the user to store arbitrary data.
+ * @free: a user supplied function to free the resource. Populated by
+ * kunit_alloc_resource().
+ *
+ * Represents a *test managed resource*, a resource which will automatically be
+ * cleaned up at the end of a test case.
+ *
+ * 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->allocation = kmalloc(params->size, params->gfp);
+ *
+ *             if (!res->allocation)
+ *                     return -ENOMEM;
+ *
+ *             return 0;
+ *     }
+ *
+ *     static void kunit_kmalloc_free(struct kunit_resource *res)
+ *     {
+ *             kfree(res->allocation);
+ *     }
+ *
+ *     void *kunit_kmalloc(struct kunit *test, size_t size, gfp_t gfp)
+ *     {
+ *             struct kunit_kmalloc_params params;
+ *             struct kunit_resource *res;
+ *
+ *             params.size = size;
+ *             params.gfp = gfp;
+ *
+ *             res = kunit_alloc_resource(test, kunit_kmalloc_init,
+ *                     kunit_kmalloc_free, &params);
+ *             if (res)
+ *                     return res->allocation;
+ *
+ *             return NULL;
+ *     }
+ */
+struct kunit_resource {
+       void *allocation;
+       kunit_resource_free_t free;
+
+       /* private: internal use only. */
+       struct list_head node;
+};
+
 struct kunit;
 
 /**
@@ -109,6 +173,13 @@ struct kunit {
         * have terminated.
         */
        bool success; /* Read only after test_case finishes! */
+       spinlock_t lock; /* Guards all mutable test state. */
+       /*
+        * Because resources is a list that may be updated multiple times (with
+        * new resources) from any thread associated with a test case, we must
+        * protect it with some type of lock.
+        */
+       struct list_head resources; /* Protected by lock. */
 };
 
 void kunit_init_test(struct kunit *test, const char *name);
@@ -141,6 +212,122 @@ int kunit_run_tests(struct kunit_suite *suite);
                }                                                              \
                late_initcall(kunit_suite_init##suite)
 
+/*
+ * Like kunit_alloc_resource() below, but returns the struct kunit_resource
+ * object that contains the allocation. This is mostly for testing purposes.
+ */
+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);
+
+/**
+ * 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.
+ * @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 each 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 = kunit_alloc_and_get_resource(test, init, free, internal_gfp,
+                                          context);
+
+       if (res)
+               return res->allocation;
+
+       return NULL;
+}
+
+typedef bool (*kunit_resource_match_t)(struct kunit *test,
+                                      const void *res,
+                                      void *match_data);
+
+/**
+ * kunit_resource_instance_match() - Match a resource with the same instance.
+ * @test: Test case to which the resource belongs.
+ * @res: The data stored in kunit_resource->allocation.
+ * @match_data: The resource pointer to match against.
+ *
+ * An instance of kunit_resource_match_t that matches a resource whose
+ * allocation matches @match_data.
+ */
+static inline bool kunit_resource_instance_match(struct kunit *test,
+                                                const void *res,
+                                                void *match_data)
+{
+       return res == match_data;
+}
+
+/**
+ * kunit_resource_destroy() - 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.
+ * @free: Must match free on the kunit_resource to free.
+ * @match_data: Data passed into @match.
+ *
+ * Free the latest kunit_resource of @test for which @free matches the
+ * kunit_resource_free_t associated with the resource and for which @match
+ * returns true.
+ *
+ * RETURNS:
+ * 0 if kunit_resource is found and freed, -ENOENT if not found.
+ */
+int kunit_resource_destroy(struct kunit *test,
+                          kunit_resource_match_t match,
+                          kunit_resource_free_t free,
+                          void *match_data);
+
+/**
+ * kunit_kmalloc() - Like kmalloc() except the allocation is *test managed*.
+ * @test: The test context object.
+ * @size: The size in bytes of the desired memory.
+ * @gfp: flags passed to underlying kmalloc().
+ *
+ * Just like `kmalloc(...)`, except the allocation is managed by the test case
+ * and is automatically cleaned up after the test case concludes. See &struct
+ * kunit_resource for more information.
+ */
+void *kunit_kmalloc(struct kunit *test, size_t size, gfp_t gfp);
+
+/**
+ * kunit_kfree() - Like kfree except for allocations managed by KUnit.
+ * @test: The test case to which the resource belongs.
+ * @ptr: The memory allocation to free.
+ */
+void kunit_kfree(struct kunit *test, const void *ptr);
+
+/**
+ * kunit_kzalloc() - Just like kunit_kmalloc(), but zeroes the allocation.
+ * @test: The test context object.
+ * @size: The size in bytes of the desired memory.
+ * @gfp: flags passed to underlying kmalloc().
+ *
+ * See kzalloc() and kunit_kmalloc() for more information.
+ */
+static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
+{
+       return kunit_kmalloc(test, size, gfp | __GFP_ZERO);
+}
+
+void kunit_cleanup(struct kunit *test);
+
 void __printf(3, 4) kunit_printk(const char *level,
                                 const struct kunit *test,
                                 const char *fmt, ...);
diff --git a/kunit/test.c b/kunit/test.c
index d3dda359f99b1..68b1037ab74d0 100644
--- a/kunit/test.c
+++ b/kunit/test.c
@@ -122,6 +122,8 @@ static void kunit_print_test_case_ok_not_ok(struct 
kunit_case *test_case,
 
 void kunit_init_test(struct kunit *test, const char *name)
 {
+       spin_lock_init(&test->lock);
+       INIT_LIST_HEAD(&test->resources);
        test->name = name;
        test->success = true;
 }
@@ -153,6 +155,8 @@ static void kunit_run_case(struct kunit_suite *suite,
        if (suite->exit)
                suite->exit(&test);
 
+       kunit_cleanup(&test);
+
        test_case->success = test.success;
 }
 
@@ -173,6 +177,165 @@ int kunit_run_tests(struct kunit_suite *suite)
        return 0;
 }
 
+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;
+
+       ret = init(res, context);
+       if (ret)
+               return NULL;
+
+       res->free = free;
+       spin_lock(&test->lock);
+       list_add_tail(&res->node, &test->resources);
+       spin_unlock(&test->lock);
+
+       return res;
+}
+
+static void kunit_resource_free(struct kunit *test, struct kunit_resource *res)
+{
+       res->free(res);
+       kfree(res);
+}
+
+static struct kunit_resource *kunit_resource_find(struct kunit *test,
+                                                 kunit_resource_match_t match,
+                                                 kunit_resource_free_t free,
+                                                 void *match_data)
+{
+       struct kunit_resource *resource;
+
+       lockdep_assert_held(&test->lock);
+
+       list_for_each_entry_reverse(resource, &test->resources, node) {
+               if (resource->free != free)
+                       continue;
+               if (match(test, resource->allocation, match_data))
+                       return resource;
+       }
+
+       return NULL;
+}
+
+static struct kunit_resource *kunit_resource_remove(
+               struct kunit *test,
+               kunit_resource_match_t match,
+               kunit_resource_free_t free,
+               void *match_data)
+{
+       struct kunit_resource *resource;
+
+       spin_lock(&test->lock);
+       resource = kunit_resource_find(test, match, free, match_data);
+       if (resource)
+               list_del(&resource->node);
+       spin_unlock(&test->lock);
+
+       return resource;
+}
+
+int kunit_resource_destroy(struct kunit *test,
+                          kunit_resource_match_t match,
+                          kunit_resource_free_t free,
+                          void *match_data)
+{
+       struct kunit_resource *resource;
+
+       resource = kunit_resource_remove(test, match, free, match_data);
+
+       if (!resource)
+               return -ENOENT;
+
+       kunit_resource_free(test, resource);
+       return 0;
+}
+
+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->allocation = kmalloc(params->size, params->gfp);
+       if (!res->allocation)
+               return -ENOMEM;
+
+       return 0;
+}
+
+static void kunit_kmalloc_free(struct kunit_resource *res)
+{
+       kfree(res->allocation);
+}
+
+void *kunit_kmalloc(struct kunit *test, size_t size, gfp_t gfp)
+{
+       struct kunit_kmalloc_params params = {
+               .size = size,
+               .gfp = gfp
+       };
+
+       return kunit_alloc_resource(test,
+                                   kunit_kmalloc_init,
+                                   kunit_kmalloc_free,
+                                   gfp,
+                                   &params);
+}
+
+void kunit_kfree(struct kunit *test, const void *ptr)
+{
+       int rc;
+
+       rc = kunit_resource_destroy(test,
+                                   kunit_resource_instance_match,
+                                   kunit_kmalloc_free,
+                                   (void *)ptr);
+
+       WARN_ON(rc);
+}
+
+void kunit_cleanup(struct kunit *test)
+{
+       struct kunit_resource *resource;
+
+       /*
+        * test->resources is a stack - each allocation must be freed in the
+        * reverse order from which it was added since one resource may depend
+        * on another for its entire lifetime.
+        * Also, we cannot use the normal list_for_each constructs, even the
+        * safe ones because *arbitrary* nodes may be deleted when
+        * kunit_resource_free is called; the list_for_each_safe variants only
+        * protect against the current node being deleted, not the next.
+        */
+       while (true) {
+               spin_lock(&test->lock);
+               if (list_empty(&test->resources)) {
+                       spin_unlock(&test->lock);
+                       break;
+               }
+               resource = list_last_entry(&test->resources,
+                                          struct kunit_resource,
+                                          node);
+               list_del(&resource->node);
+               spin_unlock(&test->lock);
+
+               kunit_resource_free(test, resource);
+       }
+}
+
 void kunit_printk(const char *level,
                  const struct kunit *test,
                  const char *fmt, ...)
-- 
2.23.0.rc1.153.gdeed80330f-goog

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