Si-Wei Liu
2022-May-17 23:59 UTC
[PATCH v7 5/5] vdpa/mlx5: Use readers/writers semaphore instead of mutex
On 5/17/2022 6:13 AM, Eli Cohen wrote:> Reading statistics could be done intensively and by several processes > concurrently. Reader's lock is sufficient in this case. > > Change reslock from mutex to a rwsem. > > Suggested-by: Si-Wei Liu <si-wei.liu at oracle.com> > Signed-off-by: Eli Cohen <elic at nvidia.com>Reviewed-by: Si-Wei Liu <si-wei.liu at oracle.com>> --- > drivers/vdpa/mlx5/net/mlx5_vnet.c | 41 ++++++++++++++----------------- > 1 file changed, 19 insertions(+), 22 deletions(-) > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c > index 2b815ef850c8..57cfc64248b7 100644 > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c > @@ -155,7 +155,7 @@ struct mlx5_vdpa_net { > * since memory map might change and we need to destroy and create > * resources while driver in operational. > */ > - struct mutex reslock; > + struct rw_semaphore reslock; > struct mlx5_flow_table *rxft; > struct mlx5_fc *rx_counter; > struct mlx5_flow_handle *rx_rule_ucast; > @@ -1695,7 +1695,7 @@ static void mlx5_cvq_kick_handler(struct work_struct *work) > ndev = to_mlx5_vdpa_ndev(mvdev); > cvq = &mvdev->cvq; > > - mutex_lock(&ndev->reslock); > + down_write(&ndev->reslock); > > if (!(mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) > goto out; > @@ -1746,7 +1746,7 @@ static void mlx5_cvq_kick_handler(struct work_struct *work) > } > > out: > - mutex_unlock(&ndev->reslock); > + up_write(&ndev->reslock); > } > > static void mlx5_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx) > @@ -2244,7 +2244,7 @@ static int setup_driver(struct mlx5_vdpa_dev *mvdev) > struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev); > int err; > > - WARN_ON(!mutex_is_locked(&ndev->reslock)); > + WARN_ON(!rwsem_is_locked(&ndev->reslock)); > > if (ndev->setup) { > mlx5_vdpa_warn(mvdev, "setup driver called for already setup driver\n"); > @@ -2292,7 +2292,7 @@ static int setup_driver(struct mlx5_vdpa_dev *mvdev) > static void teardown_driver(struct mlx5_vdpa_net *ndev) > { > > - WARN_ON(!mutex_is_locked(&ndev->reslock)); > + WARN_ON(!rwsem_is_locked(&ndev->reslock)); > > if (!ndev->setup) > return; > @@ -2322,7 +2322,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status) > > print_status(mvdev, status, true); > > - mutex_lock(&ndev->reslock); > + down_write(&ndev->reslock); > > if ((status ^ ndev->mvdev.status) & VIRTIO_CONFIG_S_DRIVER_OK) { > if (status & VIRTIO_CONFIG_S_DRIVER_OK) { > @@ -2338,14 +2338,14 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status) > } > > ndev->mvdev.status = status; > - mutex_unlock(&ndev->reslock); > + up_write(&ndev->reslock); > return; > > err_setup: > mlx5_vdpa_destroy_mr(&ndev->mvdev); > ndev->mvdev.status |= VIRTIO_CONFIG_S_FAILED; > err_clear: > - mutex_unlock(&ndev->reslock); > + up_write(&ndev->reslock); > } > > static int mlx5_vdpa_reset(struct vdpa_device *vdev) > @@ -2356,7 +2356,7 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev) > print_status(mvdev, 0, true); > mlx5_vdpa_info(mvdev, "performing device reset\n"); > > - mutex_lock(&ndev->reslock); > + down_write(&ndev->reslock); > teardown_driver(ndev); > clear_vqs_ready(ndev); > mlx5_vdpa_destroy_mr(&ndev->mvdev); > @@ -2371,7 +2371,7 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev) > if (mlx5_vdpa_create_mr(mvdev, NULL)) > mlx5_vdpa_warn(mvdev, "create MR failed\n"); > } > - mutex_unlock(&ndev->reslock); > + up_write(&ndev->reslock); > > return 0; > } > @@ -2411,7 +2411,7 @@ static int mlx5_vdpa_set_map(struct vdpa_device *vdev, struct vhost_iotlb *iotlb > bool change_map; > int err; > > - mutex_lock(&ndev->reslock); > + down_write(&ndev->reslock); > > err = mlx5_vdpa_handle_set_map(mvdev, iotlb, &change_map); > if (err) { > @@ -2423,7 +2423,7 @@ static int mlx5_vdpa_set_map(struct vdpa_device *vdev, struct vhost_iotlb *iotlb > err = mlx5_vdpa_change_map(mvdev, iotlb); > > err: > - mutex_unlock(&ndev->reslock); > + up_write(&ndev->reslock); > return err; > } > > @@ -2442,7 +2442,6 @@ static void mlx5_vdpa_free(struct vdpa_device *vdev) > mlx5_mpfs_del_mac(pfmdev, ndev->config.mac); > } > mlx5_vdpa_free_resources(&ndev->mvdev); > - mutex_destroy(&ndev->reslock); > kfree(ndev->event_cbs); > kfree(ndev->vqs); > } > @@ -2527,7 +2526,7 @@ static int mlx5_vdpa_get_vendor_vq_stats(struct vdpa_device *vdev, u16 idx, > u64 completed_desc; > int err = 0; > > - mutex_lock(&ndev->reslock); > + down_read(&ndev->reslock); > if (!is_index_valid(mvdev, idx)) { > NL_SET_ERR_MSG_MOD(extack, "virtqueue index is not valid"); > err = -EINVAL; > @@ -2566,7 +2565,7 @@ static int mlx5_vdpa_get_vendor_vq_stats(struct vdpa_device *vdev, u16 idx, > > err = 0; > out_err: > - mutex_unlock(&ndev->reslock); > + up_read(&ndev->reslock); > return err; > } > > @@ -2835,18 +2834,18 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name, > } > > init_mvqs(ndev); > - mutex_init(&ndev->reslock); > + init_rwsem(&ndev->reslock); > config = &ndev->config; > > if (add_config->mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU)) { > err = config_func_mtu(mdev, add_config->net.mtu); > if (err) > - goto err_mtu; > + goto err_alloc; > } > > err = query_mtu(mdev, &mtu); > if (err) > - goto err_mtu; > + goto err_alloc; > > ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, mtu); > > @@ -2860,14 +2859,14 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name, > } else { > err = mlx5_query_nic_vport_mac_address(mdev, 0, 0, config->mac); > if (err) > - goto err_mtu; > + goto err_alloc; > } > > if (!is_zero_ether_addr(config->mac)) { > pfmdev = pci_get_drvdata(pci_physfn(mdev->pdev)); > err = mlx5_mpfs_add_mac(pfmdev, config->mac); > if (err) > - goto err_mtu; > + goto err_alloc; > > ndev->mvdev.mlx_features |= BIT_ULL(VIRTIO_NET_F_MAC); > } > @@ -2917,8 +2916,6 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name, > err_mpfs: > if (!is_zero_ether_addr(config->mac)) > mlx5_mpfs_del_mac(pfmdev, config->mac); > -err_mtu: > - mutex_destroy(&ndev->reslock); > err_alloc: > put_device(&mvdev->vdev.dev); > return err;