• David Gibson's avatar
    [POWERPC] Allow duplicate lmb_reserve() calls · eb6de286
    David Gibson authored
    At present calling lmb_reserve() (and hence lmb_add_region()) twice
    for exactly the same memory region will cause strange behaviour.
    
    This makes life difficult when booting from a flat device tree with
    memory reserve map.  Which regions are automatically reserved by the
    kernel has changed over time, so it's quite possible a newer kernel
    could attempt to auto-reserve a region which is also explicitly listed
    in the device tree's reserve map, leading to trouble.
    
    This patch avoids the problem by making lmb_reserve() ignore a call to
    reserve a previously reserved region.  It also removes a now redundant
    test designed to avoid one specific case of the problem noted above.
    
    At present, this patch deals only with duplicate reservations of an
    identical region.  Attempting to reserve two different, but
    overlapping regions will still cause problems.  I might post another
    patch later dealing with this case, but I'm avoiding it now since it
    is substantially more complicated to deal with, less likely to occur
    and more likely to indicate a genuine bug elsewhere if it does occur.
    Signed-off-by: default avatarDavid Gibson <dwg@au1.ibm.com>
    Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    eb6de286
lmb.c 8.11 KB