• NeilBrown's avatar
    [PATCH] md: remove personality numbering from md · 2604b703
    NeilBrown authored
    md supports multiple different RAID level, each being implemented by a
    'personality' (which is often in a separate module).
    These personalities have fairly artificial 'numbers'.  The numbers
    are use to:
     1- provide an index into an array where the various personalities
        are recorded
     2- identify the module (via an alias) which implements are particular
    Neither of these uses really justify the existence of personality numbers.
    The array can be replaced by a linked list which is searched (array lookup
    only happens very rarely).  Module identification can be done using an alias
    based on level rather than 'personality' number.
    The current 'raid5' modules support two level (4 and 5) but only one
    personality.  This slight awkwardness (which was handled in the mapping from
    level to personality) can be better handled by allowing raid5 to register 2
    With this change in place, the core md module does not need to have an
    exhaustive list of all possible personalities, so other personalities can be
    added independently.
    This patch also moves the check for chunksize being non-zero into the ->run
    routines for the personalities that need it, rather than having it in core-md.
     This has a side effect of allowing 'faulty' and 'linear' not to have a
    chunk-size set.
    Signed-off-by: default avatarNeil Brown <neilb@suse.de>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
raid5.c 59.5 KB