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Subject[GIT PULL] please pull infiniband.git
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Linus, please pull from

master.kernel.org:/pub/scm/linux/kernel/git/roland/infiniband.git for-linus

This tree is also available from kernel.org mirrors at:

git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband.git for-linus

This will get one fix for a data corruption bug in 2.6.23-rc7:

Jack Morgenstein (1):
IB/mlx4: Fix data corruption triggered by wrong headroom marking order

drivers/infiniband/hw/mlx4/qp.c | 62 ++++++++++++++++++++++++++++++--------
1 files changed, 49 insertions(+), 13 deletions(-)

diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c
index ba0428d..85c51bd 100644
--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c
@@ -1211,12 +1211,42 @@ static void set_datagram_seg(struct mlx4_wqe_datagram_seg *dseg,
dseg->qkey = cpu_to_be32(wr->wr.ud.remote_qkey);
}

-static void set_data_seg(struct mlx4_wqe_data_seg *dseg,
- struct ib_sge *sg)
+static void set_mlx_icrc_seg(void *dseg)
+{
+ u32 *t = dseg;
+ struct mlx4_wqe_inline_seg *iseg = dseg;
+
+ t[1] = 0;
+
+ /*
+ * Need a barrier here before writing the byte_count field to
+ * make sure that all the data is visible before the
+ * byte_count field is set. Otherwise, if the segment begins
+ * a new cacheline, the HCA prefetcher could grab the 64-byte
+ * chunk and get a valid (!= * 0xffffffff) byte count but
+ * stale data, and end up sending the wrong data.
+ */
+ wmb();
+
+ iseg->byte_count = cpu_to_be32((1 << 31) | 4);
+}
+
+static void set_data_seg(struct mlx4_wqe_data_seg *dseg, struct ib_sge *sg)
{
- dseg->byte_count = cpu_to_be32(sg->length);
dseg->lkey = cpu_to_be32(sg->lkey);
dseg->addr = cpu_to_be64(sg->addr);
+
+ /*
+ * Need a barrier here before writing the byte_count field to
+ * make sure that all the data is visible before the
+ * byte_count field is set. Otherwise, if the segment begins
+ * a new cacheline, the HCA prefetcher could grab the 64-byte
+ * chunk and get a valid (!= * 0xffffffff) byte count but
+ * stale data, and end up sending the wrong data.
+ */
+ wmb();
+
+ dseg->byte_count = cpu_to_be32(sg->length);
}

int mlx4_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
@@ -1225,6 +1255,7 @@ int mlx4_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
struct mlx4_ib_qp *qp = to_mqp(ibqp);
void *wqe;
struct mlx4_wqe_ctrl_seg *ctrl;
+ struct mlx4_wqe_data_seg *dseg;
unsigned long flags;
int nreq;
int err = 0;
@@ -1324,22 +1355,27 @@ int mlx4_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
break;
}

- for (i = 0; i < wr->num_sge; ++i) {
- set_data_seg(wqe, wr->sg_list + i);
+ /*
+ * Write data segments in reverse order, so as to
+ * overwrite cacheline stamp last within each
+ * cacheline. This avoids issues with WQE
+ * prefetching.
+ */

- wqe += sizeof (struct mlx4_wqe_data_seg);
- size += sizeof (struct mlx4_wqe_data_seg) / 16;
- }
+ dseg = wqe;
+ dseg += wr->num_sge - 1;
+ size += wr->num_sge * (sizeof (struct mlx4_wqe_data_seg) / 16);

/* Add one more inline data segment for ICRC for MLX sends */
- if (qp->ibqp.qp_type == IB_QPT_SMI || qp->ibqp.qp_type == IB_QPT_GSI) {
- ((struct mlx4_wqe_inline_seg *) wqe)->byte_count =
- cpu_to_be32((1 << 31) | 4);
- ((u32 *) wqe)[1] = 0;
- wqe += sizeof (struct mlx4_wqe_data_seg);
+ if (unlikely(qp->ibqp.qp_type == IB_QPT_SMI ||
+ qp->ibqp.qp_type == IB_QPT_GSI)) {
+ set_mlx_icrc_seg(dseg + 1);
size += sizeof (struct mlx4_wqe_data_seg) / 16;
}

+ for (i = wr->num_sge - 1; i >= 0; --i, --dseg)
+ set_data_seg(dseg, wr->sg_list + i);
+
ctrl->fence_size = (wr->send_flags & IB_SEND_FENCE ?
MLX4_WQE_CTRL_FENCE : 0) | size;

-
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