From: Or Gerlitz <ogerl...@mellanox.com>
commit f57915cfa5b2b14c1cffa2e83c034f55e3f0e70d upstream.
This patch adds a max_send_sge=2 minimum in isert_conn_setup_qp()
to ensure outgoing control PDU responses with tx_desc->num_sge=2
are able to function correctly.
This addresses a bug with RDMA hardware using dev_attr.max_sge=3,
that in the original code with the ConnectX-2 work-around would
result in isert_conn->max_sge=1 being negotiated.
Originally reported by Chris with ocrdma driver.
Reported-by: Chris Moore <chris.mo...@emulex.com>
Tested-by: Chris Moore <chris.mo...@emulex.com>
Signed-off-by: Or Gerlitz <ogerl...@mellanox.com>
Signed-off-by: Nicholas Bellinger <n...@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/infiniband/ulp/isert/ib_isert.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c
b/drivers/infiniband/ulp/isert/ib_isert.c
index 42f5edd..0812e98 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -107,9 +107,12 @@ isert_conn_setup_qp(struct isert_conn *isert_conn, struct
rdma_cm_id *cma_id)
attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS;
/*
* FIXME: Use devattr.max_sge - 2 for max_send_sge as
- * work-around for RDMA_READ..
+ * work-around for RDMA_READs with ConnectX-2.
+ *
+ * Also, still make sure to have at least two SGEs for
+ * outgoing control PDU responses.
*/
- attr.cap.max_send_sge = devattr.max_sge - 2;
+ attr.cap.max_send_sge = max(2, devattr.max_sge - 2);
isert_conn->max_sge = attr.cap.max_send_sge;
attr.cap.max_recv_sge = 1;
--
1.8.5.3
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