Commit 0078ad90 authored by Eli Cohen's avatar Eli Cohen Committed by Michael S. Tsirkin
Browse files

net/vdpa: Use readers/writers semaphore instead of vdpa_dev_mutex 



Use rw_semaphore instead of mutex to control access to vdpa devices.
This can be especially beneficial in case processes poll on statistics
information.

Suggested-by: default avatarSi-Wei Liu <si-wei.liu@oracle.com>
Reviewed-by: default avatarSi-Wei Liu <si-wei.liu@oracle.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarEli Cohen <elic@nvidia.com>
Message-Id: <20220518133804.1075129-4-elic@nvidia.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 13b00b13

drivers/vdpa/vdpa.c

+32 −32
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ 


static LIST_HEAD(mdev_head);

/* A global mutex that protects vdpa management device and device level operations. */

static DEFINE_MUTEX(vdpa_dev_mutex);

static DECLARE_RWSEM(vdpa_dev_lock);

static DEFINE_IDA(vdpa_index_ida);



void vdpa_set_status(struct vdpa_device *vdev, u8 status)
@@ -238,7 +238,7 @@ static int __vdpa_register_device(struct vdpa_device *vdev, u32 nvqs) 


	vdev->nvqs = nvqs;



	lockdep_assert_held(&vdpa_dev_mutex);

	lockdep_assert_held(&vdpa_dev_lock);

	dev = bus_find_device(&vdpa_bus, NULL, dev_name(&vdev->dev), vdpa_name_match);

	if (dev) {

		put_device(dev);
@@ -278,9 +278,9 @@ int vdpa_register_device(struct vdpa_device *vdev, u32 nvqs) 
{

	int err;



	mutex_lock(&vdpa_dev_mutex);

	down_write(&vdpa_dev_lock);

	err = __vdpa_register_device(vdev, nvqs);

	mutex_unlock(&vdpa_dev_mutex);

	up_write(&vdpa_dev_lock);

	return err;

}

EXPORT_SYMBOL_GPL(vdpa_register_device);
@@ -293,7 +293,7 @@ EXPORT_SYMBOL_GPL(vdpa_register_device); 
 */

void _vdpa_unregister_device(struct vdpa_device *vdev)

{

	lockdep_assert_held(&vdpa_dev_mutex);

	lockdep_assert_held(&vdpa_dev_lock);

	WARN_ON(!vdev->mdev);

	device_unregister(&vdev->dev);

}
@@ -305,9 +305,9 @@ EXPORT_SYMBOL_GPL(_vdpa_unregister_device); 
 */

void vdpa_unregister_device(struct vdpa_device *vdev)

{

	mutex_lock(&vdpa_dev_mutex);

	down_write(&vdpa_dev_lock);

	device_unregister(&vdev->dev);

	mutex_unlock(&vdpa_dev_mutex);

	up_write(&vdpa_dev_lock);

}

EXPORT_SYMBOL_GPL(vdpa_unregister_device);
@@ -352,9 +352,9 @@ int vdpa_mgmtdev_register(struct vdpa_mgmt_dev *mdev) 
		return -EINVAL;



	INIT_LIST_HEAD(&mdev->list);

	mutex_lock(&vdpa_dev_mutex);

	down_write(&vdpa_dev_lock);

	list_add_tail(&mdev->list, &mdev_head);

	mutex_unlock(&vdpa_dev_mutex);

	up_write(&vdpa_dev_lock);

	return 0;

}

EXPORT_SYMBOL_GPL(vdpa_mgmtdev_register);
@@ -371,14 +371,14 @@ static int vdpa_match_remove(struct device *dev, void *data) 


void vdpa_mgmtdev_unregister(struct vdpa_mgmt_dev *mdev)

{

	mutex_lock(&vdpa_dev_mutex);

	down_write(&vdpa_dev_lock);



	list_del(&mdev->list);



	/* Filter out all the entries belong to this management device and delete it. */

	bus_for_each_dev(&vdpa_bus, NULL, mdev, vdpa_match_remove);



	mutex_unlock(&vdpa_dev_mutex);

	up_write(&vdpa_dev_lock);

}

EXPORT_SYMBOL_GPL(vdpa_mgmtdev_unregister);
@@ -532,17 +532,17 @@ static int vdpa_nl_cmd_mgmtdev_get_doit(struct sk_buff *skb, struct genl_info *i 
	if (!msg)

		return -ENOMEM;



	mutex_lock(&vdpa_dev_mutex);

	down_read(&vdpa_dev_lock);

	mdev = vdpa_mgmtdev_get_from_attr(info->attrs);

	if (IS_ERR(mdev)) {

		mutex_unlock(&vdpa_dev_mutex);

		up_read(&vdpa_dev_lock);

		NL_SET_ERR_MSG_MOD(info->extack, "Fail to find the specified mgmt device");

		err = PTR_ERR(mdev);

		goto out;

	}



	err = vdpa_mgmtdev_fill(mdev, msg, info->snd_portid, info->snd_seq, 0);

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);

	if (err)

		goto out;

	err = genlmsg_reply(msg, info);
@@ -561,7 +561,7 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb) 
	int idx = 0;

	int err;



	mutex_lock(&vdpa_dev_mutex);

	down_read(&vdpa_dev_lock);

	list_for_each_entry(mdev, &mdev_head, list) {

		if (idx < start) {

			idx++;
@@ -574,7 +574,7 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb) 
		idx++;

	}

out:

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);

	cb->args[0] = idx;

	return msg->len;

}
@@ -627,7 +627,7 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i 
	    !netlink_capable(skb, CAP_NET_ADMIN))

		return -EPERM;



	mutex_lock(&vdpa_dev_mutex);

	down_write(&vdpa_dev_lock);

	mdev = vdpa_mgmtdev_get_from_attr(info->attrs);

	if (IS_ERR(mdev)) {

		NL_SET_ERR_MSG_MOD(info->extack, "Fail to find the specified management device");
@@ -643,7 +643,7 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i 


	err = mdev->ops->dev_add(mdev, name, &config);

err:

	mutex_unlock(&vdpa_dev_mutex);

	up_write(&vdpa_dev_lock);

	return err;

}
@@ -659,7 +659,7 @@ static int vdpa_nl_cmd_dev_del_set_doit(struct sk_buff *skb, struct genl_info *i 
		return -EINVAL;

	name = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);



	mutex_lock(&vdpa_dev_mutex);

	down_write(&vdpa_dev_lock);

	dev = bus_find_device(&vdpa_bus, NULL, name, vdpa_name_match);

	if (!dev) {

		NL_SET_ERR_MSG_MOD(info->extack, "device not found");
@@ -677,7 +677,7 @@ static int vdpa_nl_cmd_dev_del_set_doit(struct sk_buff *skb, struct genl_info *i 
mdev_err:

	put_device(dev);

dev_err:

	mutex_unlock(&vdpa_dev_mutex);

	up_write(&vdpa_dev_lock);

	return err;

}
@@ -743,7 +743,7 @@ static int vdpa_nl_cmd_dev_get_doit(struct sk_buff *skb, struct genl_info *info) 
	if (!msg)

		return -ENOMEM;



	mutex_lock(&vdpa_dev_mutex);

	down_read(&vdpa_dev_lock);

	dev = bus_find_device(&vdpa_bus, NULL, devname, vdpa_name_match);

	if (!dev) {

		NL_SET_ERR_MSG_MOD(info->extack, "device not found");
@@ -761,13 +761,13 @@ static int vdpa_nl_cmd_dev_get_doit(struct sk_buff *skb, struct genl_info *info) 


	err = genlmsg_reply(msg, info);

	put_device(dev);

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);

	return err;



mdev_err:

	put_device(dev);

err:

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);

	nlmsg_free(msg);

	return err;

}
@@ -809,9 +809,9 @@ static int vdpa_nl_cmd_dev_get_dumpit(struct sk_buff *msg, struct netlink_callba 
	info.start_idx = cb->args[0];

	info.idx = 0;



	mutex_lock(&vdpa_dev_mutex);

	down_read(&vdpa_dev_lock);

	bus_for_each_dev(&vdpa_bus, NULL, &info, vdpa_dev_dump);

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);

	cb->args[0] = info.idx;

	return msg->len;

}
@@ -1031,7 +1031,7 @@ static int vdpa_nl_cmd_dev_config_get_doit(struct sk_buff *skb, struct genl_info 
	if (!msg)

		return -ENOMEM;



	mutex_lock(&vdpa_dev_mutex);

	down_read(&vdpa_dev_lock);

	dev = bus_find_device(&vdpa_bus, NULL, devname, vdpa_name_match);

	if (!dev) {

		NL_SET_ERR_MSG_MOD(info->extack, "device not found");
@@ -1052,7 +1052,7 @@ static int vdpa_nl_cmd_dev_config_get_doit(struct sk_buff *skb, struct genl_info 
mdev_err:

	put_device(dev);

dev_err:

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);

	if (err)

		nlmsg_free(msg);

	return err;
@@ -1090,9 +1090,9 @@ vdpa_nl_cmd_dev_config_get_dumpit(struct sk_buff *msg, struct netlink_callback * 
	info.start_idx = cb->args[0];

	info.idx = 0;



	mutex_lock(&vdpa_dev_mutex);

	down_read(&vdpa_dev_lock);

	bus_for_each_dev(&vdpa_bus, NULL, &info, vdpa_dev_config_dump);

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);

	cb->args[0] = info.idx;

	return msg->len;

}
@@ -1119,7 +1119,7 @@ static int vdpa_nl_cmd_dev_stats_get_doit(struct sk_buff *skb, 
		return -ENOMEM;



	index = nla_get_u32(info->attrs[VDPA_ATTR_DEV_QUEUE_INDEX]);

	mutex_lock(&vdpa_dev_mutex);

	down_read(&vdpa_dev_lock);

	dev = bus_find_device(&vdpa_bus, NULL, devname, vdpa_name_match);

	if (!dev) {

		NL_SET_ERR_MSG_MOD(info->extack, "device not found");
@@ -1139,7 +1139,7 @@ static int vdpa_nl_cmd_dev_stats_get_doit(struct sk_buff *skb, 
	err = genlmsg_reply(msg, info);



	put_device(dev);

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);



	return err;
@@ -1147,7 +1147,7 @@ static int vdpa_nl_cmd_dev_stats_get_doit(struct sk_buff *skb, 
	put_device(dev);

dev_err:

	nlmsg_free(msg);

	mutex_unlock(&vdpa_dev_mutex);

	up_read(&vdpa_dev_lock);

	return err;

}