4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Kalderon, Michal" Michal.Kalderon@cavium.com
[ Upstream commit c3594f22302cca5e924e47ec1cc8edd265708f41 ]
QPs that were configured with ack timeout value lower than 1 msec will not implement re-transmission timeout. This means that if a packet / ACK were dropped, the QP will not retransmit this packet.
This can lead to an application hang.
Fixes: cecbcddf6 ("qedr: Add support for QP verbs") Signed-off-by: Michal Kalderon Michal.Kalderon@cavium.com Signed-off-by: Ariel Elior Ariel.Elior@cavium.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/infiniband/hw/qedr/verbs.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-)
--- a/drivers/infiniband/hw/qedr/verbs.c +++ b/drivers/infiniband/hw/qedr/verbs.c @@ -1888,18 +1888,23 @@ int qedr_modify_qp(struct ib_qp *ibqp, s SET_FIELD(qp_params.modify_flags, QED_ROCE_MODIFY_QP_VALID_ACK_TIMEOUT, 1);
- qp_params.ack_timeout = attr->timeout; - if (attr->timeout) { - u32 temp; - - temp = 4096 * (1UL << attr->timeout) / 1000 / 1000; - /* FW requires [msec] */ - qp_params.ack_timeout = temp; - } else { - /* Infinite */ + /* The received timeout value is an exponent used like this: + * "12.7.34 LOCAL ACK TIMEOUT + * Value representing the transport (ACK) timeout for use by + * the remote, expressed as: 4.096 * 2^timeout [usec]" + * The FW expects timeout in msec so we need to divide the usec + * result by 1000. We'll approximate 1000~2^10, and 4.096 ~ 2^2, + * so we get: 2^2 * 2^timeout / 2^10 = 2^(timeout - 8). + * The value of zero means infinite so we use a 'max_t' to make + * sure that sub 1 msec values will be configured as 1 msec. + */ + if (attr->timeout) + qp_params.ack_timeout = + 1 << max_t(int, attr->timeout - 8, 0); + else qp_params.ack_timeout = 0; - } } + if (attr_mask & IB_QP_RETRY_CNT) { SET_FIELD(qp_params.modify_flags, QED_ROCE_MODIFY_QP_VALID_RETRY_CNT, 1);