[git patch review 6/7] IB/mthca: Fix IB_QP_ACCESS_FLAGS handling.

From: Roland Dreier
Date: Thu Dec 15 2005 - 23:01:12 EST


This patch corrects some corner cases in managing the RAE/RRE bits in
the mthca qp context. These bits need to be zero if the user requests
max_dest_rd_atomic of zero. The bits need to be restored to the value
implied by the qp access flags attribute in a previous (or the
current) modify-qp command if the dest_rd_atomic variable is changed
to non-zero.

In the current implementation, the following scenario will not work:
RESET-to-INIT set QP access flags to all disabled (zeroes)
INIT-to-RTR set max_dest_rd_atomic=10, AND
set qp_access_flags = IB_ACCESS_REMOTE_READ | IB_ACCESS_REMOTE_ATOMIC

The current code will incorrectly take the access-flags value set in
the RESET-to-INIT transition.

We can simplify, and correct, this IB_QP_ACCESS_FLAGS handling: it is
always safe to set qp access flags in the firmware command if either
of IB_QP_MAX_DEST_RD_ATOMIC or IB_QP_ACCESS_FLAGS is set, so let's
just set it to the correct value, always.

Signed-off-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxxxxxx>
Signed-off-by: Roland Dreier <rolandd@xxxxxxxxx>

---

drivers/infiniband/hw/mthca/mthca_qp.c | 87 ++++++++++++++------------------
1 files changed, 37 insertions(+), 50 deletions(-)

d1646f86a2a05a956adbb163c81a81bd621f055e
diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c
index 3543299..e826c9f 100644
--- a/drivers/infiniband/hw/mthca/mthca_qp.c
+++ b/drivers/infiniband/hw/mthca/mthca_qp.c
@@ -522,6 +522,36 @@ static void init_port(struct mthca_dev *
mthca_warn(dev, "INIT_IB returned status %02x.\n", status);
}

+static __be32 get_hw_access_flags(struct mthca_qp *qp, struct ib_qp_attr *attr,
+ int attr_mask)
+{
+ u8 dest_rd_atomic;
+ u32 access_flags;
+ u32 hw_access_flags = 0;
+
+ if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
+ dest_rd_atomic = attr->max_dest_rd_atomic;
+ else
+ dest_rd_atomic = qp->resp_depth;
+
+ if (attr_mask & IB_QP_ACCESS_FLAGS)
+ access_flags = attr->qp_access_flags;
+ else
+ access_flags = qp->atomic_rd_en;
+
+ if (!dest_rd_atomic)
+ access_flags &= IB_ACCESS_REMOTE_WRITE;
+
+ if (access_flags & IB_ACCESS_REMOTE_READ)
+ hw_access_flags |= MTHCA_QP_BIT_RRE;
+ if (access_flags & IB_ACCESS_REMOTE_ATOMIC)
+ hw_access_flags |= MTHCA_QP_BIT_RAE;
+ if (access_flags & IB_ACCESS_REMOTE_WRITE)
+ hw_access_flags |= MTHCA_QP_BIT_RWE;
+
+ return cpu_to_be32(hw_access_flags);
+}
+
int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
{
struct mthca_dev *dev = to_mdev(ibqp->device);
@@ -743,57 +773,7 @@ int mthca_modify_qp(struct ib_qp *ibqp,
qp_context->snd_db_index = cpu_to_be32(qp->sq.db_index);
}

- if (attr_mask & IB_QP_ACCESS_FLAGS) {
- qp_context->params2 |=
- cpu_to_be32(attr->qp_access_flags & IB_ACCESS_REMOTE_WRITE ?
- MTHCA_QP_BIT_RWE : 0);
-
- /*
- * Only enable RDMA reads and atomics if we have
- * responder resources set to a non-zero value.
- */
- if (qp->resp_depth) {
- qp_context->params2 |=
- cpu_to_be32(attr->qp_access_flags & IB_ACCESS_REMOTE_READ ?
- MTHCA_QP_BIT_RRE : 0);
- qp_context->params2 |=
- cpu_to_be32(attr->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC ?
- MTHCA_QP_BIT_RAE : 0);
- }
-
- qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RWE |
- MTHCA_QP_OPTPAR_RRE |
- MTHCA_QP_OPTPAR_RAE);
- }
-
if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC) {
- if (qp->resp_depth && !attr->max_dest_rd_atomic) {
- /*
- * Lowering our responder resources to zero.
- * Turn off reads RDMA and atomics as responder.
- * (RRE/RAE in params2 already zero)
- */
- qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RRE |
- MTHCA_QP_OPTPAR_RAE);
- }
-
- if (!qp->resp_depth && attr->max_dest_rd_atomic) {
- /*
- * Increasing our responder resources from
- * zero. Turn on RDMA reads and atomics as
- * appropriate.
- */
- qp_context->params2 |=
- cpu_to_be32(qp->atomic_rd_en & IB_ACCESS_REMOTE_READ ?
- MTHCA_QP_BIT_RRE : 0);
- qp_context->params2 |=
- cpu_to_be32(qp->atomic_rd_en & IB_ACCESS_REMOTE_ATOMIC ?
- MTHCA_QP_BIT_RAE : 0);
-
- qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RRE |
- MTHCA_QP_OPTPAR_RAE);
- }
-
if (attr->max_dest_rd_atomic)
qp_context->params2 |=
cpu_to_be32(fls(attr->max_dest_rd_atomic - 1) << 21);
@@ -801,6 +781,13 @@ int mthca_modify_qp(struct ib_qp *ibqp,
qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RRA_MAX);
}

+ if (attr_mask & (IB_QP_ACCESS_FLAGS | IB_QP_MAX_DEST_RD_ATOMIC)) {
+ qp_context->params2 |= get_hw_access_flags(qp, attr, attr_mask);
+ qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RWE |
+ MTHCA_QP_OPTPAR_RRE |
+ MTHCA_QP_OPTPAR_RAE);
+ }
+
qp_context->params2 |= cpu_to_be32(MTHCA_QP_BIT_RSC);

if (ibqp->srq)
--
0.99.9n
-
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