Commit 759ae7f9 authored by Eli Cohen's avatar Eli Cohen Committed by Michael S. Tsirkin
Browse files

vdpa/mlx5: Use readers/writers semaphore instead of mutex 



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: default avatarSi-Wei Liu <si-wei.liu@oracle.com>
Signed-off-by: default avatarEli Cohen <elic@nvidia.com>
Message-Id: <20220518133804.1075129-7-elic@nvidia.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 1892a3d4

drivers/vdpa/mlx5/net/mlx5_vnet.c

+19 −22
Original line number Diff line number Diff line
@@ -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;