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Subject[patch 02/33] IB/mthca: Fix data corruption after FMR unmap on Sinai
-stable review patch.  If anyone has any objections, please let us know.

From: Michael S. Tsirkin <>
In mthca_arbel_fmr_unmap(), the high bits of the key are masked off.
This gets rid of the effect of adjust_key(), which makes sure that
bits 3 and 23 of the key are equal when the Sinai throughput
optimization is enabled, and so it may happen that an FMR will end up
with bits 3 and 23 in the key being different. This causes data
corruption, because when enabling the throughput optimization, the
driver promises the HCA firmware that bits 3 and 23 of all memory keys
will always be equal.

Fix by re-applying adjust_key() after masking the key.

Thanks to Or Gerlitz for reproducing the problem, and Ariel Shahar for
help in debug.

Signed-off-by: Michael S. Tsirkin <>
Signed-off-by: Roland Dreier <>
Signed-off-by: Greg Kroah-Hartman <>

drivers/infiniband/hw/mthca/mthca_mr.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/infiniband/hw/mthca/mthca_mr.c
+++ b/drivers/infiniband/hw/mthca/mthca_mr.c
@@ -751,6 +751,7 @@ void mthca_arbel_fmr_unmap(struct mthca_

key = arbel_key_to_hw_index(fmr->ibmr.lkey);
key &= dev->limits.num_mpts - 1;
+ key = adjust_key(dev, key);
fmr->ibmr.lkey = fmr->ibmr.rkey = arbel_hw_index_to_key(key);

fmr->maps = 0;
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