Thread (3 messages) 3 messages, 3 authors, 2021-08-09

Re: [PATCH for-rc] RDMA/cma: Revert INIT-INIT patch

From: Haakon Bugge <hidden>
Date: 2021-08-09 12:20:55

On 29 Jul 2021, at 20:26, mike.marciniszyn@cornelisnetworks.com wrote:

From: Mike Marciniszyn <redacted>

The net/sunrpc/xprtrdma module creates its QP using rdma_create_qp() and
immediately post receives, implicitly assuming the QP is in the INIT
state and thus valid for ib_post_recv().

The patch noted in Fixes: removed the RESET->INIT modifiy from
rdma_create_qp(), breaking NFS rdma for verbs providers that fail the
ib_post_recv() for a bad state.

This situation was proven using kprobes in rvt_post_recv() and
rvt_modify_qp(). The traces showed that the rvt_post_recv() failed before
ANY modify QP and that the current state was RESET.

Fix by reverting the patch below.

Fixes: dc70f7c3ed34 ("RDMA/cma: Remove unnecessary INIT->INIT transition")
Cc: Haakon Bugge <redacted>
Cc: Chuck Lever III <chuck.lever@oracle.com>
Signed-off-by: Mike Marciniszyn <redacted>
Reviewed-by: Håkon Bugge <redacted>


Thxs, Håkon
quoted hunk ↗ jump to hunk
---
drivers/infiniband/core/cma.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 515a7e9..5d3b8b8 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -926,12 +926,25 @@ static int cma_init_ud_qp(struct rdma_id_private *id_priv, struct ib_qp *qp)
	return ret;
}

+static int cma_init_conn_qp(struct rdma_id_private *id_priv, struct ib_qp *qp)
+{
+	struct ib_qp_attr qp_attr;
+	int qp_attr_mask, ret;
+
+	qp_attr.qp_state = IB_QPS_INIT;
+	ret = rdma_init_qp_attr(&id_priv->id, &qp_attr, &qp_attr_mask);
+	if (ret)
+		return ret;
+
+	return ib_modify_qp(qp, &qp_attr, qp_attr_mask);
+}
+
int rdma_create_qp(struct rdma_cm_id *id, struct ib_pd *pd,
		   struct ib_qp_init_attr *qp_init_attr)
{
	struct rdma_id_private *id_priv;
	struct ib_qp *qp;
-	int ret = 0;
+	int ret;

	id_priv = container_of(id, struct rdma_id_private, id);
	if (id->device != pd->device) {
@@ -948,6 +961,8 @@ int rdma_create_qp(struct rdma_cm_id *id, struct ib_pd *pd,
	if (id->qp_type == IB_QPT_UD)
		ret = cma_init_ud_qp(id_priv, qp);
+	else
+		ret = cma_init_conn_qp(id_priv, qp);
	if (ret)
		goto out_destroy;

-- 
1.8.3.1
  
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