• Kirill Tkhai's avatar
    uts: Use generic ns_common::count · 9a56493f
    Kirill Tkhai authored
    Switch over uts namespaces to use the newly introduced common lifetime
    counter.
    
    Currently every namespace type has its own lifetime counter which is stored
    in the specific namespace struct. The lifetime counters are used
    identically for all namespaces types. Namespaces may of course have
    additional unrelated counters and these are not altered.
    
    This introduces a common lifetime counter into struct ns_common. The
    ns_common struct encompasses information that all namespaces share. That
    should include the lifetime counter since its common for all of them.
    
    It also allows us to unify the type of the counters across all namespaces.
    Most of them use refcount_t but one uses atomic_t and at least one uses
    kref. Especially the last one doesn't make much sense since it's just a
    wrapper around refcount_t since 2016 and actually complicates cleanup
    operations by having to use container_of() to cast the correct namespace
    struct out of struct ns_common.
    
    Having the lifetime counter for the namespaces in one place reduces
    maintenance cost. Not just because after switching all namespaces over we
    will have removed more code than we added but also because the logic is
    more easily understandable and we indicate to the user that the basic
    lifetime requirements for all namespaces are currently identical.
    Signed-off-by: default avatarKirill Tkhai <ktkhai@virtuozzo.com>
    Reviewed-by: default avatarKees Cook <keescook@chromium.org>
    Acked-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
    Link: https://lore.kernel.org/r/159644978167.604812.1773586504374412107.stgit@localhost.localdomainSigned-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
    9a56493f
utsname.c 3.76 KB