Re: [PATCH net-next] devlink: Set device as early as possible
From: Prabhakar Kushwaha
Date: Tue Aug 10 2021 - 08:39:42 EST
Hi Leon,
On Mon, Aug 9, 2021 at 12:33 AM Leon Romanovsky <leon@xxxxxxxxxx> wrote:
>
> From: Leon Romanovsky <leonro@xxxxxxxxxx>
>
> All kernel devlink implementations call to devlink_alloc() during
> initialization routine for specific device which is used later as
> a parent device for devlink_register().
>
> Such late device assignment causes to the situation which requires us to
> call to device_register() before setting other parameters, but that call
> opens devlink to the world and makes accessible for the netlink users.
>
> Any attempt to move devlink_register() to be the last call generates the
> following error due to access to the devlink->dev pointer.
>
> [ 8.758862] devlink_nl_param_fill+0x2e8/0xe50
> [ 8.760305] devlink_param_notify+0x6d/0x180
> [ 8.760435] __devlink_params_register+0x2f1/0x670
> [ 8.760558] devlink_params_register+0x1e/0x20
>
> The simple change of API to set devlink device in the devlink_alloc()
> instead of devlink_register() fixes all this above and ensures that
> prior to call to devlink_register() everything already set.
>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
> ---
> .../net/ethernet/broadcom/bnxt/bnxt_devlink.c | 9 ++++---
> .../net/ethernet/cavium/liquidio/lio_main.c | 5 ++--
> .../freescale/dpaa2/dpaa2-eth-devlink.c | 5 ++--
> .../hisilicon/hns3/hns3pf/hclge_devlink.c | 4 +--
> .../hisilicon/hns3/hns3vf/hclgevf_devlink.c | 7 ++---
> .../net/ethernet/huawei/hinic/hinic_devlink.c | 8 +++---
> .../net/ethernet/huawei/hinic/hinic_devlink.h | 4 +--
> .../net/ethernet/huawei/hinic/hinic_hw_dev.c | 2 +-
> .../net/ethernet/huawei/hinic/hinic_main.c | 2 +-
> drivers/net/ethernet/intel/ice/ice_devlink.c | 4 +--
> .../marvell/octeontx2/af/rvu_devlink.c | 5 ++--
> .../marvell/prestera/prestera_devlink.c | 7 ++---
> .../marvell/prestera/prestera_devlink.h | 2 +-
> .../ethernet/marvell/prestera/prestera_main.c | 2 +-
> drivers/net/ethernet/mellanox/mlx4/main.c | 4 +--
> .../net/ethernet/mellanox/mlx5/core/devlink.c | 9 ++++---
> .../net/ethernet/mellanox/mlx5/core/devlink.h | 4 +--
> .../net/ethernet/mellanox/mlx5/core/main.c | 4 +--
> .../mellanox/mlx5/core/sf/dev/driver.c | 2 +-
> drivers/net/ethernet/mellanox/mlxsw/core.c | 5 ++--
> drivers/net/ethernet/mscc/ocelot_vsc7514.c | 5 ++--
> drivers/net/ethernet/netronome/nfp/nfp_main.c | 2 +-
> .../net/ethernet/netronome/nfp/nfp_net_main.c | 2 +-
> .../ethernet/pensando/ionic/ionic_devlink.c | 4 +--
> drivers/net/ethernet/qlogic/qed/qed_devlink.c | 5 ++--
> drivers/net/ethernet/ti/am65-cpsw-nuss.c | 4 +--
> drivers/net/ethernet/ti/cpsw_new.c | 4 +--
> drivers/net/netdevsim/dev.c | 4 +--
> drivers/ptp/ptp_ocp.c | 26 +++----------------
> drivers/staging/qlge/qlge_main.c | 5 ++--
> include/net/devlink.h | 10 ++++---
> net/core/devlink.c | 15 +++++------
> net/dsa/dsa2.c | 5 ++--
> 33 files changed, 91 insertions(+), 94 deletions(-)
>
<snip>
>
> diff --git a/include/net/devlink.h b/include/net/devlink.h
> index ccbfb3a844aa..0236c77f2fd0 100644
> --- a/include/net/devlink.h
> +++ b/include/net/devlink.h
> @@ -1544,13 +1544,15 @@ struct net *devlink_net(const struct devlink *devlink);
> * Drivers that operate on real HW must use devlink_alloc() instead.
> */
> struct devlink *devlink_alloc_ns(const struct devlink_ops *ops,
> - size_t priv_size, struct net *net);
> + size_t priv_size, struct net *net,
> + struct device *dev);
> static inline struct devlink *devlink_alloc(const struct devlink_ops *ops,
> - size_t priv_size)
> + size_t priv_size,
> + struct device *dev)
> {
> - return devlink_alloc_ns(ops, priv_size, &init_net);
> + return devlink_alloc_ns(ops, priv_size, &init_net, dev);
> }
> -int devlink_register(struct devlink *devlink, struct device *dev);
> +int devlink_register(struct devlink *devlink);
> void devlink_unregister(struct devlink *devlink);
> void devlink_reload_enable(struct devlink *devlink);
> void devlink_reload_disable(struct devlink *devlink);
> diff --git a/net/core/devlink.c b/net/core/devlink.c
> index ee95eee8d0ed..d3b16dd9f64e 100644
> --- a/net/core/devlink.c
> +++ b/net/core/devlink.c
> @@ -8768,24 +8768,26 @@ static bool devlink_reload_actions_valid(const struct devlink_ops *ops)
> * @ops: ops
> * @priv_size: size of user private data
> * @net: net namespace
> + * @dev: parent device
> *
> * Allocate new devlink instance resources, including devlink index
> * and name.
> */
> struct devlink *devlink_alloc_ns(const struct devlink_ops *ops,
> - size_t priv_size, struct net *net)
> + size_t priv_size, struct net *net,
> + struct device *dev)
> {
> struct devlink *devlink;
>
> - if (WARN_ON(!ops))
> - return NULL;
> -
> + WARN_ON(!ops || !dev);
> if (!devlink_reload_actions_valid(ops))
> return NULL;
>
> devlink = kzalloc(sizeof(*devlink) + priv_size, GFP_KERNEL);
> if (!devlink)
> return NULL;
> +
> + devlink->dev = dev;
> devlink->ops = ops;
> xa_init_flags(&devlink->snapshot_ids, XA_FLAGS_ALLOC);
> write_pnet(&devlink->_net, net);
> @@ -8810,12 +8812,9 @@ EXPORT_SYMBOL_GPL(devlink_alloc_ns);
> * devlink_register - Register devlink instance
> *
> * @devlink: devlink
> - * @dev: parent device
> */
This patch is converting devlink_alloc() to devlink_alloc_register().
There are 2 APIs: devlink_alloc() and devlink_register().
Both APIs can be used in a scenario,
Where devlink_alloc() can be done by code written around
one struct dev and used by another struct dev.
or
This scenario is not even a valid scenario?
> -int devlink_register(struct devlink *devlink, struct device *dev)
> +int devlink_register(struct devlink *devlink)
> {
> - WARN_ON(devlink->dev);
> - devlink->dev = dev;
> mutex_lock(&devlink_mutex);
> list_add_tail(&devlink->list, &devlink_list);
> devlink_notify(devlink, DEVLINK_CMD_NEW);
Considering device registration has been moved to devlink_alloc().
Can the remaining code of devlink_register() be also moved in devlink_alloc()?
--pk