The patch below does not apply to the 3.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f57915cfa5b2b14c1cffa2e83c034f55e3f0e70d Mon Sep 17 00:00:00 2001 From: Or Gerlitz <ogerlitz@xxxxxxxxxxxx> Date: Wed, 22 Oct 2014 14:55:49 -0700 Subject: [PATCH] ib_isert: Add max_send_sge=2 minimum for control PDU responses 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@xxxxxxxxxx> Tested-by: Chris Moore <Chris.Moore@xxxxxxxxxx> Signed-off-by: Or Gerlitz <ogerlitz@xxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # 3.10+ Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c index 3effa931fce2..ef5b22b3ea83 100644 --- a/drivers/infiniband/ulp/isert/ib_isert.c +++ b/drivers/infiniband/ulp/isert/ib_isert.c @@ -115,9 +115,12 @@ 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; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html