Commit:     eb6de2863750e696201780283e4c9ada19b4728e
Parent:     83ddcf5d364be7b1d8c214d2dd97753e1df589cd
Author:     David Gibson <[EMAIL PROTECTED]>
AuthorDate: Wed Feb 28 14:12:29 2007 +1100
Committer:  Paul Mackerras <[EMAIL PROTECTED]>
CommitDate: Thu Mar 8 15:43:28 2007 +1100

    [POWERPC] Allow duplicate lmb_reserve() calls
    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: David Gibson <[EMAIL PROTECTED]>
    Signed-off-by: Paul Mackerras <[EMAIL PROTECTED]>
 arch/powerpc/kernel/prom.c |    3 ---
 arch/powerpc/mm/lmb.c      |    4 ++++
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 8d52b23..15ece3a 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -954,9 +954,6 @@ static void __init early_reserve_mem(void)
                size = *(reserve_map++);
                if (size == 0)
-               /* skip if the reservation is for the blob */
-               if (base == self_base && size == self_size)
-                       continue;
                DBG("reserving: %llx -> %llx\n", base, size);
                lmb_reserve(base, size);
diff --git a/arch/powerpc/mm/lmb.c b/arch/powerpc/mm/lmb.c
index 716a290..e3a1e8d 100644
--- a/arch/powerpc/mm/lmb.c
+++ b/arch/powerpc/mm/lmb.c
@@ -146,6 +146,10 @@ static long __init lmb_add_region(struct lmb_region *rgn, 
unsigned long base,
                unsigned long rgnbase = rgn->region[i].base;
                unsigned long rgnsize = rgn->region[i].size;
+               if ((rgnbase == base) && (rgnsize == size))
+                       /* Already have this region, so we're done */
+                       return 0;
                adjacent = lmb_addrs_adjacent(base,size,rgnbase,rgnsize);
                if ( adjacent > 0 ) {
                        rgn->region[i].base -= size;
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