• David Gow's avatar
    kunit: Expose 'static stub' API to redirect functions · e047c5ea
    David Gow authored
    Add a simple way of redirecting calls to functions by including a
    special prologue in the "real" function which checks to see if the
    replacement function should be called (and, if so, calls it).
    
    To redirect calls to a function, make the first (non-declaration) line
    of the function:
    
    	KUNIT_STATIC_STUB_REDIRECT(function_name, [function arguments]);
    
    (This will compile away to nothing if KUnit is not enabled, otherwise it
    will check if a redirection is active, call the replacement function,
    and return. This check is protected by a static branch, so has very
    little overhead when there are no KUnit tests running.)
    
    Calls to the real function can be redirected to a replacement using:
    
    	kunit_activate_static_stub(test, real_fn, replacement_fn);
    
    The redirection will only affect calls made from within the kthread of
    the current test, and will be automatically disabled when the test
    completes. It can also be manually disabled with
    kunit_deactivate_static_stub().
    
    The 'example' KUnit test suite has a more complete example.
    Co-developed-by: default avatarDaniel Latypov <dlatypov@google.com>
    Signed-off-by: default avatarDaniel Latypov <dlatypov@google.com>
    Signed-off-by: default avatarDavid Gow <davidgow@google.com>
    Reviewed-by: default avatarBrendan Higgins <brendanhiggins@google.com>
    Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
    e047c5ea
static_stub.h 3.6 KB