Hi David,
Looks great, thanks for sending a second version
On Fri, Mar 31, 2023 at 04:04:09PM +0800, David Gow wrote:
Many uses of the KUnit resource system are intended to simply defer calling a function until the test exits (be it due to success or failure). The existing kunit_alloc_resource() function is often used for this, but was awkward to use (requiring passing NULL init functions, etc), and returned a resource without incrementing its reference count, which -- while okay for this use-case -- could cause problems in others.
Instead, introduce a simple kunit_add_action() API: a simple function (returning nothing, accepting a single void* argument) can be scheduled to be called when the test exits. Deferred actions are called in the opposite order to that which they were registered.
This mimics the devres API, devm_add_action(), and also provides kunit_remove_action(), to cancel a deferred action, and kunit_release_action() to trigger one early.
This is implemented as a resource under the hood, so the ordering between resource cleanup and deferred functions is maintained.
Signed-off-by: David Gow davidgow@google.com
Changes since RFC v1: https://lore.kernel.org/linux-kselftest/20230325043104.3761770-2-davidgow@go...
- Rename functions to better match the devm_* APIs. (Thanks Maxime)
- Embed the kunit_resource in struct kunit_action_ctx to avoid an extra allocation (Thanks Benjamin)
- Use 'struct kunit_action_ctx' as the type for cancellation tokens (Thanks Benjamin)
- Add tests.
include/kunit/resource.h | 89 ++++++++++++++++++++++++++++ lib/kunit/kunit-test.c | 123 ++++++++++++++++++++++++++++++++++++++- lib/kunit/resource.c | 99 +++++++++++++++++++++++++++++++ 3 files changed, 310 insertions(+), 1 deletion(-)
diff --git a/include/kunit/resource.h b/include/kunit/resource.h index c0d88b318e90..15efd8924666 100644 --- a/include/kunit/resource.h +++ b/include/kunit/resource.h @@ -387,4 +387,93 @@ static inline int kunit_destroy_named_resource(struct kunit *test, */ void kunit_remove_resource(struct kunit *test, struct kunit_resource *res); +typedef void (*kunit_defer_function_t)(void *ctx);
+/* An opaque token to a deferred action. */ +struct kunit_action_ctx;
+/**
- kunit_add_action() - Defer an 'action' (function call) until the test ends.
- @test: Test case to associate the action with.
- @func: The function to run on test exit
- @ctx: Data passed into @func
- @internal_gfp: gfp to use for internal allocations, if unsure, use GFP_KERNEL
- 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.
- Returns:
- An opaque "cancellation token", or NULL on error. Pass this token to
- kunit_remove_action_token() in order to cancel the deferred execution of
- func().
- */
+struct kunit_action_ctx *kunit_add_action(struct kunit *test, kunit_defer_function_t func,
void *ctx, gfp_t internal_gfp);
Do we expect any other context than GFP_KERNEL?
If so, then maybe we can have kunit_add_action() assume GFP_KERNEL and add a variant for the odd case where we would actually need a different GFP flag.
+/**
- kunit_remove_action_token() - Cancel a deferred action.
- @test: Test case the action is associated with.
- @cancel_token: The cancellation token returned by kunit_add_action()
- Prevent an action deferred using kunit_add_action() from executing when the
- test ends.
- You can also use the (test, function, context) triplet to remove an action
- with kunit_remove_action().
- */
+void kunit_remove_action_token(struct kunit *test, struct kunit_action_ctx *cancel_token);
It's not clear to me why we still need the token. If kunit_remove_action() works fine, why would we need to store the token?
Can't we just make kunit_add_action() return an int to indicate whether it failed or not, and that's it?
+/**
- kunit_release_action_token() - Trigger a deferred action immediately.
- @test: Test case the action is associated with.
- @cancel_token: The cancellation token returned by kunit_add_action()
- Execute an action immediately, instead of waiting for the test to end.
- You can also use the (test, function, context) triplet to trigger an action
- with kunit_release_action().
- */
+void kunit_release_action_token(struct kunit *test, struct kunit_action_ctx *cancel_token);
+/**
- kunit_remove_action() - Cancel a matching deferred action.
- @test: Test case the action is associated with.
- @func: 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..
- Unlike kunit_remove_action_token(), this takes the (func, ctx) pair instead of
- the cancellation token. If that function/context pair was deferred multiple
- times, only the most recent one will be cancelled.
- */
+void kunit_remove_action(struct kunit *test,
kunit_defer_function_t func,void *ctx);+/**
- kunit_release_action() - Run a matching action call immediately.
- @test: Test case the action is associated with.
- @func: 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.
- Unlike kunit_release_action_token(), this takes the (func, ctx) pair instead of
- the cancellation token. If that 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);
- */
+void kunit_release_action(struct kunit *test,
kunit_defer_function_t func,void *ctx);#endif /* _KUNIT_RESOURCE_H */ diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index b63595d3e241..eaca1b133922 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -111,7 +111,7 @@ struct kunit_test_resource_context { struct kunit test; bool is_resource_initialized; int allocate_order[2];
- int free_order[2];
- int free_order[4];
}; static int fake_resource_init(struct kunit_resource *res, void *context) @@ -402,6 +402,123 @@ static void kunit_resource_test_named(struct kunit *test) KUNIT_EXPECT_TRUE(test, list_empty(&test->resources)); } +static void increment_int(void *ctx) +{
- int *i = (int *)ctx;
- (*i)++;
+}
+static void kunit_resource_test_action(struct kunit *test) +{
- int num_actions = 0;
- kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- KUNIT_EXPECT_EQ(test, num_actions, 0);
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 1);
- /* Once we've cleaned up, the action queue is empty. */
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 1);
- /* Check the same function can be deferred multiple times. */
- kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 3);
+} +static void kunit_resource_test_remove_action(struct kunit *test) +{
- int num_actions = 0;
- struct kunit_action_ctx *cancel_token;
- struct kunit_action_ctx *cancel_token2;
- cancel_token = kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- KUNIT_EXPECT_EQ(test, num_actions, 0);
- kunit_remove_action_token(test, cancel_token);
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 0);
- /* Check calls from the same function/context pair can be cancelled independently*/
- cancel_token = kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- cancel_token2 = kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- kunit_remove_action_token(test, cancel_token);
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 1);
- /* Also check that we can cancel just one of the identical function/context pairs. */
- cancel_token = kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- cancel_token2 = kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- kunit_remove_action(test, increment_int, &num_actions);
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 2);
+} +static void kunit_resource_test_release_action(struct kunit *test) +{
- int num_actions = 0;
- struct kunit_action_ctx *cancel_token;
- struct kunit_action_ctx *cancel_token2;
- cancel_token = kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- KUNIT_EXPECT_EQ(test, num_actions, 0);
- /* Runs immediately on trigger. */
- kunit_release_action_token(test, cancel_token);
- KUNIT_EXPECT_EQ(test, num_actions, 1);
- /* Doesn't run again on test exit. */
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 1);
- /* Check calls from the same function/context pair can be triggered independently*/
- cancel_token = kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- cancel_token2 = kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- kunit_release_action_token(test, cancel_token);
- KUNIT_EXPECT_EQ(test, num_actions, 2);
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 3);
- /* Also check that we can trigger just one of the identical function/context pairs. */
- kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- kunit_add_action(test, increment_int, &num_actions, GFP_KERNEL);
- kunit_release_action(test, increment_int, &num_actions);
- KUNIT_EXPECT_EQ(test, num_actions, 4);
- kunit_cleanup(test);
- KUNIT_EXPECT_EQ(test, num_actions, 5);
+} +static void action_order_1(void *ctx) +{
- struct kunit_test_resource_context *res_ctx = (struct kunit_test_resource_context *)ctx;
- KUNIT_RESOURCE_TEST_MARK_ORDER(res_ctx, free_order, 1);
- kunit_log(KERN_INFO, current->kunit_test, "action_order_1");
+} +static void action_order_2(void *ctx) +{
- struct kunit_test_resource_context *res_ctx = (struct kunit_test_resource_context *)ctx;
- KUNIT_RESOURCE_TEST_MARK_ORDER(res_ctx, free_order, 2);
- kunit_log(KERN_INFO, current->kunit_test, "action_order_2");
+} +static void kunit_resource_test_action_ordering(struct kunit *test) +{
- struct kunit_test_resource_context *ctx = test->priv;
- struct kunit_action_ctx *cancel_token;
- kunit_add_action(test, action_order_1, ctx, GFP_KERNEL);
- cancel_token = kunit_add_action(test, action_order_2, ctx, GFP_KERNEL);
- kunit_add_action(test, action_order_1, ctx, GFP_KERNEL);
- kunit_add_action(test, action_order_2, ctx, GFP_KERNEL);
- kunit_remove_action(test, action_order_1, ctx);
- kunit_release_action_token(test, cancel_token);
- kunit_cleanup(test);
- /* [2 is triggered] [2], [(1 is cancelled)] [1] */
- KUNIT_EXPECT_EQ(test, ctx->free_order[0], 2);
- KUNIT_EXPECT_EQ(test, ctx->free_order[1], 2);
- KUNIT_EXPECT_EQ(test, ctx->free_order[2], 1);
+}
static int kunit_resource_test_init(struct kunit *test) { struct kunit_test_resource_context *ctx = @@ -433,6 +550,10 @@ static struct kunit_case kunit_resource_test_cases[] = { KUNIT_CASE(kunit_resource_test_proper_free_ordering), KUNIT_CASE(kunit_resource_test_static), KUNIT_CASE(kunit_resource_test_named),
- KUNIT_CASE(kunit_resource_test_action),
- KUNIT_CASE(kunit_resource_test_remove_action),
- KUNIT_CASE(kunit_resource_test_release_action),
- KUNIT_CASE(kunit_resource_test_action_ordering), {}
}; diff --git a/lib/kunit/resource.c b/lib/kunit/resource.c index c414df922f34..824cf91e306d 100644 --- a/lib/kunit/resource.c +++ b/lib/kunit/resource.c @@ -77,3 +77,102 @@ int kunit_destroy_resource(struct kunit *test, kunit_resource_match_t match, return 0; } EXPORT_SYMBOL_GPL(kunit_destroy_resource);
+struct kunit_action_ctx {
- struct kunit_resource res;
- kunit_defer_function_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);
+}
+struct kunit_action_ctx *kunit_add_action(struct kunit *test, kunit_defer_function_t func,
void *ctx, gfp_t internal_gfp)+{
- struct kunit_action_ctx *action_ctx;
- KUNIT_ASSERT_NOT_NULL_MSG(test, func, "Tried to action a NULL function!");
- action_ctx = kzalloc(sizeof(*action_ctx), internal_gfp);
- if (!action_ctx)
return NULL;- action_ctx->func = func;
- 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 action_ctx;
+}
One thing worth pointing is that if kunit_add_action() fails, the cleanup function passed as an argument won't run.
So, if the kzalloc call ever fails, patch 2 will leak its res->data() resource for example.
devm (and drmm) handles this using a variant called devm_add_action_or_reset, we should either provide the same variant or just go for that behavior by default.
Maxime