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    rtnl: make link af-specific updates atomic · cf7afbfe
    Thomas Graf 提交于
    As David pointed out correctly, updates to af-specific attributes
    are currently not atomic. If multiple changes are requested and
    one of them fails, previous updates may have been applied already
    leaving the link behind in a undefined state.
    
    This patch splits the function parse_link_af() into two functions
    validate_link_af() and set_link_at(). validate_link_af() is placed
    to validate_linkmsg() check for errors as early as possible before
    any changes to the link have been made. set_link_af() is called to
    commit the changes later.
    
    This method is not fail proof, while it is currently sufficient
    to make set_link_af() inerrable and thus 100% atomic, the
    validation function method will not be able to detect all error
    scenarios in the future, there will likely always be errors
    depending on states which are f.e. not protected by rtnl_mutex
    and thus may change between validation and setting.
    
    Also, instead of silently ignoring unknown address families and
    config blocks for address families which did not register a set
    function the errors EAFNOSUPPORT respectively EOPNOSUPPORT are
    returned to avoid comitting 4 out of 5 update requests without
    notifying the user.
    Signed-off-by: NThomas Graf <tgraf@infradead.org>
    Signed-off-by: NDavid S. Miller <davem@davemloft.net>
    cf7afbfe
rtnetlink.c 46.1 KB