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_defer() API: a simple function (returning nothing, accepting a single void* argument) can be scheduled to be called when the test exits. Deferred functions are called in the opposite order to that which they were registered.
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 --- include/kunit/resource.h | 87 +++++++++++++++++++++++++++++++ lib/kunit/resource.c | 110 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 197 insertions(+)
diff --git a/include/kunit/resource.h b/include/kunit/resource.h index cf6fb8f2ac1b..6c4728ca9237 100644 --- a/include/kunit/resource.h +++ b/include/kunit/resource.h @@ -387,4 +387,91 @@ 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); + +/** + * kunit_defer() - Defer a function call until the test ends. + * @test: Test case to associate the deferred function 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_defer() 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_defer_cancel() in order to cancel the deferred execution of func(). + */ +void *kunit_defer(struct kunit *test, kunit_defer_function_t func, + void *ctx, gfp_t internal_gfp); + +/** + * kunit_defer_cancel_token() - Cancel a deferred function call. + * @test: Test case the deferred function is associated with. + * @cancel_token: The cancellation token returned by kunit_defer() + * + * Prevent a function deferred using kunit_defer() from executing when the + * test ends. + * + * Prefer using this to kunit_defer_cancel() where possible. + */ +void kunit_defer_cancel_token(struct kunit *test, void *cancel_token); + +/** + * kunit_defer_trigger_token() - Run a deferred function call immediately. + * @test: Test case the deferred function is associated with. + * @cancel_token: The cancellation token returned by kunit_defer() + * + * Execute a deferred function call immediately, instead of waiting for the + * test to end. + * + * Prefer using this to kunit_defer_trigger() where possible. + */ +void kunit_defer_trigger_token(struct kunit *test, void *cancel_token); + +/** + * kunit_defer_cancel() - Cancel a matching deferred function call. + * @test: Test case the deferred function is associated with. + * @func: The deferred function to cancel. + * @ctx: The context passed to the deferred function to trigger. + * + * Prevent a function deferred via kunit_defer() from executing at shutdown. + * Unlike kunit_defer_cancel_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. + * + * Prefer using kunit_defer_cancel_token() to this where possible. + */ +void kunit_defer_cancel(struct kunit *test, + kunit_defer_function_t func, + void *ctx); + +/** + * kunit_defer_trigger() - Run a matching deferred function call immediately. + * @test: Test case the deferred function 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_defer() immediately, rather than when + * the test ends. + * Unlike kunit_defer_trigger_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_defer_trigger(test, func, ctx); + * is equivalent to + * func(ctx); + * kunit_defer_cancel(test, func, ctx); + * + * Prefer using kunit_defer_trigger_token() to this where possible. + */ +void kunit_defer_trigger(struct kunit *test, + kunit_defer_function_t func, + void *ctx); #endif /* _KUNIT_RESOURCE_H */ diff --git a/lib/kunit/resource.c b/lib/kunit/resource.c index c414df922f34..0d0c48054d45 100644 --- a/lib/kunit/resource.c +++ b/lib/kunit/resource.c @@ -77,3 +77,113 @@ int kunit_destroy_resource(struct kunit *test, kunit_resource_match_t match, return 0; } EXPORT_SYMBOL_GPL(kunit_destroy_resource); + +struct kunit_defer_ctx { + kunit_defer_function_t func; + void *ctx; +}; + +static void __kunit_defer_free(struct kunit_resource *res) +{ + struct kunit_defer_ctx *defer_ctx = (struct kunit_defer_ctx *)res->data; + + defer_ctx->func(defer_ctx->ctx); + + kfree(res->data); +} + +void *kunit_defer(struct kunit *test, kunit_defer_function_t func, + void *ctx, gfp_t internal_gfp) +{ + struct kunit_resource *res; + struct kunit_defer_ctx *defer_ctx; + + KUNIT_ASSERT_NOT_NULL_MSG(test, func, "Tried to defer a NULL function!"); + + res = kzalloc(sizeof(*res), internal_gfp); + if (!res) + return NULL; + + defer_ctx = kzalloc(sizeof(*defer_ctx), internal_gfp); + if (!defer_ctx) + goto free_res; + + defer_ctx->func = func; + defer_ctx->ctx = ctx; + + res->should_kfree = true; + __kunit_add_resource(test, NULL, __kunit_defer_free, res, defer_ctx); + + return (void *)res; + +free_res: + kfree(res); + return NULL; +} + +void kunit_defer_cancel_token(struct kunit *test, void *cancel_token) +{ + struct kunit_resource *res = (struct kunit_resource *)cancel_token; + + /* Remove the free function so we don't run the deferred function. */ + res->free = NULL; + + kunit_remove_resource(test, res); +} + +void kunit_defer_trigger_token(struct kunit *test, void *cancel_token) +{ + struct kunit_resource *res = (struct kunit_resource *)cancel_token; + + /* Removing the resource should trigger the res->free function. */ + kunit_remove_resource(test, res); +} + +static bool __kunit_defer_match(struct kunit *test, + struct kunit_resource *res, void *match_data) +{ + struct kunit_defer_ctx *match_ctx = (struct kunit_defer_ctx *)match_data; + struct kunit_defer_ctx *res_ctx = (struct kunit_defer_ctx *)res->data; + + /* Make sure this is a free function. */ + if (res->free != __kunit_defer_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_defer_cancel(struct kunit *test, + kunit_defer_function_t func, + void *ctx) +{ + struct kunit_defer_ctx defer_ctx; + struct kunit_resource *res; + + defer_ctx.func = func; + defer_ctx.ctx = ctx; + + res = kunit_find_resource(test, __kunit_defer_match, &defer_ctx); + if (res) { + kunit_defer_cancel_token(test, res); + kunit_put_resource(res); + } +} + +void kunit_defer_trigger(struct kunit *test, + kunit_defer_function_t func, + void *ctx) +{ + struct kunit_defer_ctx defer_ctx; + struct kunit_resource *res; + + defer_ctx.func = func; + defer_ctx.ctx = ctx; + + res = kunit_find_resource(test, __kunit_defer_match, &defer_ctx); + if (res) { + kunit_defer_trigger_token(test, res); + /* We have to put() this here, else free won't be called. */ + kunit_put_resource(res); + } +}