Commit:     532c3b581725e2c6480a20c845fff920690286f1
Parent:     3f114853d4f7c1746389f26e1d500887294da8fd
Author:     Roland Dreier <[EMAIL PROTECTED]>
AuthorDate: Tue Apr 24 16:31:04 2007 -0700
Committer:  Roland Dreier <[EMAIL PROTECTED]>
CommitDate: Tue Apr 24 16:31:04 2007 -0700

    IB/mthca: Fix mthca_write_mtt() on HCAs with hidden memory
    Commit b2875d4c ("IB/mthca: Always fill MTTs from CPU") causes a crash
    in mthca_write_mtt() with non-memfree HCAs that have their memory
    hidden (that is, have only two PCI BARs instead of having a third BAR
    that allows access to the RAM attached to the HCA) on 64-bit
    architectures.  This is because the commit just before, c20e20ab
    ("IB/mthca: Merge MR and FMR space on 64-bit systems") makes
    dev->mr_table.fmr_mtt_buddy equal to &dev->mr_table.mtt_buddy and
    hence mthca_write_mtt() tries to write directly into the HCA's MTT
    table.  However, since that table is in the HCA's memory, this is
    impossible without the PCI BAR that gives access to that memory.
    This causes a crash because mthca_tavor_write_mtt_seg() basically
    tries to dereference some offset of a NULL pointer.  Fix this by
    adding a test of MTHCA_FLAG_FMR in mthca_write_mtt() so that we always
    use the WRITE_MTT firmware command rather than writing directly if
    FMRs are not enabled.
    Signed-off-by: Roland Dreier <[EMAIL PROTECTED]>
 drivers/infiniband/hw/mthca/mthca_mr.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mthca/mthca_mr.c 
index ee561c5..aa6c70a 100644
--- a/drivers/infiniband/hw/mthca/mthca_mr.c
+++ b/drivers/infiniband/hw/mthca/mthca_mr.c
@@ -297,7 +297,8 @@ out:
 int mthca_write_mtt_size(struct mthca_dev *dev)
-       if (dev->mr_table.fmr_mtt_buddy != &dev->mr_table.mtt_buddy)
+       if (dev->mr_table.fmr_mtt_buddy != &dev->mr_table.mtt_buddy ||
+           !(dev->mthca_flags & MTHCA_FLAG_FMR))
                 * Be friendly to WRITE_MTT command
                 * and leave two empty slots for the
@@ -355,7 +356,8 @@ int mthca_write_mtt(struct mthca_dev *dev, struct mthca_mtt 
        int size = mthca_write_mtt_size(dev);
        int chunk;
-       if (dev->mr_table.fmr_mtt_buddy != &dev->mr_table.mtt_buddy)
+       if (dev->mr_table.fmr_mtt_buddy != &dev->mr_table.mtt_buddy ||
+           !(dev->mthca_flags & MTHCA_FLAG_FMR))
                return __mthca_write_mtt(dev, mtt, start_index, buffer_list, 
        while (list_len > 0) {
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