3.18-stable review patch.  If anyone has any objections, please let me know.


From: Jack Morgenstein <ja...@dev.mellanox.co.il>

commit 852f6927594d0d3e8632c889b2ab38cbc46476ad upstream.

Allocating steerable UD QPs depends on having at least one IB port,
while releasing those QPs does not.

As a result, when there are only ETH ports, the IB (RoCE) driver
requests releasing a qp range whose base qp is zero, with
qp count zero.

When SR-IOV is enabled, and the VF driver is running on a VM over
a hypervisor which treats such qp release calls as errors
(rather than NOPs), we see lines in the VM message log like:

 mlx4_core 0002:00:02.0: Failed to release qp range base:0 cnt:0

Fix this by adding a check for a zero count in mlx4_release_qp_range()
(which thus treats releasing 0 qps as a nop), and eliminating the
check for device managed flow steering when releasing steerable UD QPs.
(Freeing ib_uc_qpns_bitmap unconditionally is also OK, since it
remains NULL when steerable UD QPs are not allocated).

Fixes: 4196670be786 ("IB/mlx4: Don't allocate range of steerable UD QPs for 
Ethernet-only device")
Signed-off-by: Jack Morgenstein <ja...@dev.mellanox.co.il>
Signed-off-by: Leon Romanovsky <l...@kernel.org>
Signed-off-by: Jason Gunthorpe <j...@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

 drivers/infiniband/hw/mlx4/main.c       |   13 +++++--------
 drivers/net/ethernet/mellanox/mlx4/qp.c |    3 +++
 2 files changed, 8 insertions(+), 8 deletions(-)

--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -2348,9 +2348,8 @@ err_steer_free_bitmap:
-       if (ibdev->steering_support == MLX4_STEERING_MODE_DEVICE_MANAGED)
-               mlx4_qp_release_range(dev, ibdev->steer_qpn_base,
-                                     ibdev->steer_qpn_count);
+       mlx4_qp_release_range(dev, ibdev->steer_qpn_base,
+                             ibdev->steer_qpn_count);
        for (; i; --i)
                if (ibdev->counters[i - 1] != -1)
@@ -2452,11 +2451,9 @@ static void mlx4_ib_remove(struct mlx4_d
                ibdev->iboe.nb.notifier_call = NULL;
-       if (ibdev->steering_support == MLX4_STEERING_MODE_DEVICE_MANAGED) {
-               mlx4_qp_release_range(dev, ibdev->steer_qpn_base,
-                                     ibdev->steer_qpn_count);
-               kfree(ibdev->ib_uc_qpns_bitmap);
-       }
+       mlx4_qp_release_range(dev, ibdev->steer_qpn_base,
+                             ibdev->steer_qpn_count);
+       kfree(ibdev->ib_uc_qpns_bitmap);
        if (ibdev->iboe.nb_inet.notifier_call) {
                if (unregister_inetaddr_notifier(&ibdev->iboe.nb_inet))
--- a/drivers/net/ethernet/mellanox/mlx4/qp.c
+++ b/drivers/net/ethernet/mellanox/mlx4/qp.c
@@ -257,6 +257,9 @@ void mlx4_qp_release_range(struct mlx4_d
        u64 in_param = 0;
        int err;
+       if (!cnt)
+               return;
        if (mlx4_is_mfunc(dev)) {
                set_param_l(&in_param, base_qpn);
                set_param_h(&in_param, cnt);

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