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@xxxxxxxxxx> > --- > > Changes since RFC v1: > https://lore.kernel.org/linux-kselftest/20230325043104.3761770-2-davidgow@xxxxxxxxxx/ > - 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
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