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

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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: Si-Wei Liu <si-wei.liu@oracle.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eli Cohen <elic@nvidia.com>
Message-Id: <20220518133804.1075129-4-elic@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Eli Cohen 2022-05-18 16:38:01 +03:00 committed by Michael S. Tsirkin
parent 13b00b1356
commit 0078ad905d
1 changed files with 32 additions and 32 deletions
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64
drivers/vdpa/vdpa.c
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@ -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 @@ mdev_err:
put_device(dev);
dev_err:
nlmsg_free(msg);
mutex_unlock(&vdpa_dev_mutex);
up_read(&vdpa_dev_lock);
return err;
}