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authorOr Gerlitz <ogerlitz@mellanox.com>2014-10-22 14:55:49 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-12-06 15:55:35 -0800
commit31c0b88814911924830f35e04a9b3dbb3f82f0e0 (patch)
treecb90c4353cea2d9315b3ffeb74d8d198c05cd707
parent82c138e535c22082e81ccd32a2c73edd0e101f70 (diff)
ib_isert: Add max_send_sge=2 minimum for control PDU responses
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.Moore@emulex.com> Tested-by: Chris Moore <Chris.Moore@emulex.com> Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/infiniband/ulp/isert/ib_isert.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 868d5a25e4d3..b1195b184902 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -112,9 +112,12 @@ 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 = device->dev_attr.max_sge - 2;
+ attr.cap.max_send_sge = max(2, device->dev_attr.max_sge - 2);
isert_conn->max_sge = attr.cap.max_send_sge;
attr.cap.max_recv_sge = 1;