Thread (5 messages) 5 messages, 4 authors, 2021-08-10

Re: [PATCH net-next] devlink: Set device as early as possible

From: Prabhakar Kushwaha <hidden>
Date: 2021-08-10 12:39:42
Also in: intel-wired-lan, linux-omap, lkml, netdev

Hi Leon,

On Mon, Aug 9, 2021 at 12:33 AM Leon Romanovsky [off-list ref] wrote:
From: Leon Romanovsky <leonro@nvidia.com>

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@nvidia.com>
---
 .../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>
quoted hunk ↗ jump to hunk
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
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