[patch 065/104] IB/mlx4: Fix MTT leakage in resize CQ

From: Greg KH
Date: Wed Dec 03 2008 - 15:15:51 EST

2.6.27-stable review patch. If anyone has any objections, please let us know.

From: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>

commit 42ab01c31526ac1d06d193f81a498bf3cf2acfe4 upstream.

When resizing a CQ, MTTs associated with the old CQE buffer were not
freed. As a result, if any app used resize CQ repeatedly, all MTTs
were eventually exhausted, which led to all memory registration
operations failing until the driver is reloaded.

Once the RESIZE_CQ command returns successfully from FW, FW no longer
accesses the old CQ buffer, so it is safe to deallocate the MTT
entries used by the old CQ buffer.

Finally, if the RESIZE_CQ command fails, the MTTs allocated for the
new CQEs buffer also need to be de-allocated.

This fixes <https://bugs.openfabrics.org/show_bug.cgi?id=1416>.

Signed-off-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Roland Dreier <rolandd@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

drivers/infiniband/hw/mlx4/cq.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/infiniband/hw/mlx4/cq.c
+++ b/drivers/infiniband/hw/mlx4/cq.c
@@ -343,6 +343,7 @@ int mlx4_ib_resize_cq(struct ib_cq *ibcq
struct mlx4_ib_dev *dev = to_mdev(ibcq->device);
struct mlx4_ib_cq *cq = to_mcq(ibcq);
+ struct mlx4_mtt mtt;
int outst_cqe;
int err;

@@ -376,10 +377,13 @@ int mlx4_ib_resize_cq(struct ib_cq *ibcq
goto out;

+ mtt = cq->buf.mtt;
err = mlx4_cq_resize(dev->dev, &cq->mcq, entries, &cq->resize_buf->buf.mtt);
if (err)
goto err_buf;

+ mlx4_mtt_cleanup(dev->dev, &mtt);
if (ibcq->uobject) {
cq->buf = cq->resize_buf->buf;
cq->ibcq.cqe = cq->resize_buf->cqe;
@@ -406,6 +410,7 @@ int mlx4_ib_resize_cq(struct ib_cq *ibcq
goto out;

+ mlx4_mtt_cleanup(dev->dev, &cq->resize_buf->buf.mtt);
if (!ibcq->uobject)
mlx4_ib_free_cq_buf(dev, &cq->resize_buf->buf,

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/