[v9,02/18] kunit: test: add test resource management API
diff mbox series

Message ID 20190712081744.87097-3-brendanhiggins@google.com
State Not Applicable
Headers show
Series
  • kunit: introduce KUnit, the Linux kernel unit testing framework
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Commit Message

Brendan Higgins July 12, 2019, 8:17 a.m. UTC
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 <brendanhiggins@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
---
 include/kunit/test.h | 116 +++++++++++++++++++++++++++++++++++++++++++
 kunit/test.c         |  94 +++++++++++++++++++++++++++++++++++
 2 files changed, 210 insertions(+)

Comments

Stephen Boyd July 15, 2019, 8:24 p.m. UTC | #1
Quoting Brendan Higgins (2019-07-12 01:17:28)
> diff --git a/kunit/test.c b/kunit/test.c
> index 571e4c65deb5c..f165c9d8e10b0 100644
> --- a/kunit/test.c
> +++ b/kunit/test.c
> @@ -171,6 +175,96 @@ int kunit_run_tests(struct kunit_suite *suite)
>         return 0;
>  }
>  
> +struct kunit_resource *kunit_alloc_resource(struct kunit *test,
> +                                           kunit_resource_init_t init,
> +                                           kunit_resource_free_t free,
> +                                           void *context)
> +{
> +       struct kunit_resource *res;
> +       int ret;
> +
> +       res = kzalloc(sizeof(*res), GFP_KERNEL);

This uses GFP_KERNEL.

> +       if (!res)
> +               return NULL;
> +
> +       ret = init(res, context);
> +       if (ret)
> +               return NULL;
> +
> +       res->free = free;
> +       mutex_lock(&test->lock);

And this can sleep.

> +       list_add_tail(&res->node, &test->resources);
> +       mutex_unlock(&test->lock);
> +
> +       return res;
> +}
> +
> +void kunit_free_resource(struct kunit *test, struct kunit_resource *res)

Should probably add a note that we assume the test lock is held here, or
even add a lockdep_assert_held(&test->lock) into the function to
document that and assert it at the same time.

> +{
> +       res->free(res);
> +       list_del(&res->node);
> +       kfree(res);
> +}
> +
> +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,

This calls that sleeping function above...

> +                                  kunit_kmalloc_init,
> +                                  kunit_kmalloc_free,
> +                                  &params);

but this passes a GFP flags parameter through to the
kunit_kmalloc_init() function. How is this going to work if some code
uses GFP_ATOMIC, but then we try to allocate and sleep in
kunit_alloc_resource() with GFP_KERNEL? 

One solution would be to piggyback on all the existing devres allocation
logic we already have and make each struct kunit a device that we pass
into the devres functions. A far simpler solution would be to just
copy/paste what devres does and use a spinlock and an allocation
function that takes GFP flags.

> +
> +       if (res)
> +               return res->allocation;
> +
> +       return NULL;
> +}
Brendan Higgins July 15, 2019, 8:30 p.m. UTC | #2
On Mon, Jul 15, 2019 at 1:24 PM Stephen Boyd <sboyd@kernel.org> wrote:
>
> Quoting Brendan Higgins (2019-07-12 01:17:28)
> > diff --git a/kunit/test.c b/kunit/test.c
> > index 571e4c65deb5c..f165c9d8e10b0 100644
> > --- a/kunit/test.c
> > +++ b/kunit/test.c
> > @@ -171,6 +175,96 @@ int kunit_run_tests(struct kunit_suite *suite)
> >         return 0;
> >  }
> >
> > +struct kunit_resource *kunit_alloc_resource(struct kunit *test,
> > +                                           kunit_resource_init_t init,
> > +                                           kunit_resource_free_t free,
> > +                                           void *context)
> > +{
> > +       struct kunit_resource *res;
> > +       int ret;
> > +
> > +       res = kzalloc(sizeof(*res), GFP_KERNEL);
>
> This uses GFP_KERNEL.
>
> > +       if (!res)
> > +               return NULL;
> > +
> > +       ret = init(res, context);
> > +       if (ret)
> > +               return NULL;
> > +
> > +       res->free = free;
> > +       mutex_lock(&test->lock);
>
> And this can sleep.
>
> > +       list_add_tail(&res->node, &test->resources);
> > +       mutex_unlock(&test->lock);
> > +
> > +       return res;
> > +}
> > +
> > +void kunit_free_resource(struct kunit *test, struct kunit_resource *res)
>
> Should probably add a note that we assume the test lock is held here, or
> even add a lockdep_assert_held(&test->lock) into the function to
> document that and assert it at the same time.

Seems reasonable.

> > +{
> > +       res->free(res);
> > +       list_del(&res->node);
> > +       kfree(res);
> > +}
> > +
> > +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,
>
> This calls that sleeping function above...
>
> > +                                  kunit_kmalloc_init,
> > +                                  kunit_kmalloc_free,
> > +                                  &params);
>
> but this passes a GFP flags parameter through to the
> kunit_kmalloc_init() function. How is this going to work if some code
> uses GFP_ATOMIC, but then we try to allocate and sleep in
> kunit_alloc_resource() with GFP_KERNEL?

Yeah, that's an inconsistency. I need to fix that.

> One solution would be to piggyback on all the existing devres allocation
> logic we already have and make each struct kunit a device that we pass
> into the devres functions. A far simpler solution would be to just
> copy/paste what devres does and use a spinlock and an allocation
> function that takes GFP flags.

Yeah, that's what I did originally, but I thought from the discussion
on patch 01 that you thought a spinlock was overkill for struct kunit.
I take it you only meant in that initial patch?

> > +
> > +       if (res)
> > +               return res->allocation;
> > +
> > +       return NULL;
> > +}

Cheers
Stephen Boyd July 15, 2019, 8:51 p.m. UTC | #3
Quoting Brendan Higgins (2019-07-15 13:30:22)
> On Mon, Jul 15, 2019 at 1:24 PM Stephen Boyd <sboyd@kernel.org> wrote:
> >
> > Quoting Brendan Higgins (2019-07-12 01:17:28)
> > > diff --git a/kunit/test.c b/kunit/test.c
> > > index 571e4c65deb5c..f165c9d8e10b0 100644
> 
> > One solution would be to piggyback on all the existing devres allocation
> > logic we already have and make each struct kunit a device that we pass
> > into the devres functions. A far simpler solution would be to just
> > copy/paste what devres does and use a spinlock and an allocation
> > function that takes GFP flags.
> 
> Yeah, that's what I did originally, but I thought from the discussion
> on patch 01 that you thought a spinlock was overkill for struct kunit.
> I take it you only meant in that initial patch?

Correct. I was only talking about the success bit in there.

Patch
diff mbox series

diff --git a/include/kunit/test.h b/include/kunit/test.h
index e0b34acb9ee4e..bdf41d31c343c 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -10,6 +10,70 @@ 
 #define _KUNIT_TEST_H
 
 #include <linux/types.h>
+#include <linux/slab.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! */
+	struct mutex lock; /* Gaurds 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 +212,51 @@  int kunit_run_tests(struct kunit_suite *suite);
 		}							       \
 		late_initcall(kunit_suite_init##suite)
 
+/**
+ * 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.
+ * @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.
+ */
+struct kunit_resource *kunit_alloc_resource(struct kunit *test,
+					    kunit_resource_init_t init,
+					    kunit_resource_free_t free,
+					    void *context);
+
+void kunit_free_resource(struct kunit *test, struct kunit_resource *res);
+
+/**
+ * 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_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 571e4c65deb5c..f165c9d8e10b0 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)
 {
+	mutex_init(&test->lock);
+	INIT_LIST_HEAD(&test->resources);
 	test->name = name;
 	test->success = true;
 }
@@ -151,6 +153,8 @@  static void kunit_run_case(struct kunit_suite *suite,
 	if (suite->exit)
 		suite->exit(&test);
 
+	kunit_cleanup(&test);
+
 	test_case->success = test.success;
 }
 
@@ -171,6 +175,96 @@  int kunit_run_tests(struct kunit_suite *suite)
 	return 0;
 }
 
+struct kunit_resource *kunit_alloc_resource(struct kunit *test,
+					    kunit_resource_init_t init,
+					    kunit_resource_free_t free,
+					    void *context)
+{
+	struct kunit_resource *res;
+	int ret;
+
+	res = kzalloc(sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return NULL;
+
+	ret = init(res, context);
+	if (ret)
+		return NULL;
+
+	res->free = free;
+	mutex_lock(&test->lock);
+	list_add_tail(&res->node, &test->resources);
+	mutex_unlock(&test->lock);
+
+	return res;
+}
+
+void kunit_free_resource(struct kunit *test, struct kunit_resource *res)
+{
+	res->free(res);
+	list_del(&res->node);
+	kfree(res);
+}
+
+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;
+}
+
+void kunit_cleanup(struct kunit *test)
+{
+	struct kunit_resource *resource, *resource_safe;
+
+	mutex_lock(&test->lock);
+	/*
+	 * 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.
+	 */
+	list_for_each_entry_safe_reverse(resource,
+					 resource_safe,
+					 &test->resources,
+					 node) {
+		kunit_free_resource(test, resource);
+	}
+	mutex_unlock(&test->lock);
+}
+
 void kunit_printk(const char *level,
 		  const struct kunit *test,
 		  const char *fmt, ...)