• Alan Maguire's avatar
    kunit: generalize kunit_resource API beyond allocated resources · d4cdd146
    Alan Maguire authored
    In its original form, the kunit resources API - consisting the
    struct kunit_resource and associated functions - was focused on
    adding allocated resources during test operation that would be
    automatically cleaned up on test completion.
    
    The recent RFC patch proposing converting KASAN tests to KUnit [1]
    showed another potential model - where outside of test context,
    but with a pointer to the test state, we wish to access/update
    test-related data, but expressly want to avoid allocations.
    
    It turns out we can generalize the kunit_resource to support
    static resources where the struct kunit_resource * is passed
    in and initialized for us. As part of this work, we also
    change the "allocation" field to the more general "data" name,
    as instead of associating an allocation, we can associate a
    pointer to static data.  Static data is distinguished by a NULL
    free functions.  A test is added to cover using kunit_add_resource()
    with a static resource and data.
    
    Finally we also make use of the kernel's krefcount interfaces
    to manage reference counting of KUnit resources.  The motivation
    for this is simple; if we have kernel threads accessing and
    using resources (say via kunit_find_resource()) we need to
    ensure we do not remove said resources (or indeed free them
    if they were dynamically allocated) until the reference count
    reaches zero.  A new function - kunit_put_resource() - is
    added to handle this, and it should be called after a
    thread using kunit_find_resource() is finished with the
    retrieved resource.
    
    We ensure that the functions needed to look up, use and
    drop reference count are "static inline"-defined so that
    they can be used by builtin code as well as modules in
    the case that KUnit is built as a module.
    
    A cosmetic change here also; I've tried moving to
    kunit_[action]_resource() as the format of function names
    for consistency and readability.
    
    [1] https://lkml.org/lkml/2020/2/26/1286Signed-off-by: default avatarAlan Maguire <alan.maguire@oracle.com>
    Reviewed-by: default avatarBrendan Higgins <brendanhiggins@google.com>
    Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
    d4cdd146
kunit-test.c 10.5 KB