Hi,
I do like having such an API for automatic cleanup.
On Sat, 2023-03-25 at 12:31 +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_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.
I separately proposed kunit_add_cleanup. Which I find quite descriptive and it matches the name that the python unittest package uses.
- @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);
Maybe return struct kunit_defer_ctx* instead of void? No need to have the structure itself be visible.
+/**
- 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; +};
You could avoid an allocation by embedding struct kunit_resource.
+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); + } +}