Re: [PATCH net-next 07/11] netdev: expose DPLL pin handle for netdevice

On 01/08/2023 14:23, Vadim Fedorenko wrote:

On 20/07/2023 10:18, Vadim Fedorenko wrote:

quoted

From: Jiri Pirko <redacted>

In case netdevice represents a SyncE port, the user needs to understand
the connection between netdevice and associated DPLL pin. There might me
multiple netdevices pointing to the same pin, in case of VF/SF
implementation.

Add a IFLA Netlink attribute to nest the DPLL pin handle, similar to
how it is implemented for devlink port. Add a struct dpll_pin pointer
to netdev and protect access to it by RTNL. Expose netdev_dpll_pin_set()
and netdev_dpll_pin_clear() helpers to the drivers so they can set/clear
the DPLL pin relationship to netdev.

Note that during the lifetime of struct dpll_pin the pin handle does not
change. Therefore it is save to access it lockless. It is drivers
responsibility to call netdev_dpll_pin_clear() before dpll_pin_put().

Signed-off-by: Jiri Pirko <redacted>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
---
RFC v9->v0:
- rearrange function definition according to usage
v8->v9:
- net_device->dpll_pin is only valid if IS_ENABLED(CONFIG_DPLL) fix the
   code in net/core/rtnetlink.c to respect that.
- move dpll_msg_add_pin_handle to "dpll: netlink" patch + export the
   function with this patch

  drivers/dpll/dpll_netlink.c  | 19 ++++++++++++++++---
  include/linux/dpll.h         | 20 ++++++++++++++++++++
  include/linux/netdevice.h    | 20 ++++++++++++++++++++
  include/uapi/linux/if_link.h |  2 ++
  net/core/dev.c               | 22 ++++++++++++++++++++++
  net/core/rtnetlink.c         | 35 +++++++++++++++++++++++++++++++++++
  6 files changed, 115 insertions(+), 3 deletions(-)

diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index c44dda78737d..e4a9bd767b92 100644
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c

@@ -37,6 +37,18 @@ dpll_msg_add_dev_handle(struct sk_buff *msg, struct 

dpll_device *dpll)
      return 0;
  }
+/**
+ * dpll_msg_pin_handle_size - get size of pin handle attribute for 
given pin
+ * @pin: pin pointer
+ *
+ * Return: byte size of pin handle attribute for given pin.
+ */
+size_t dpll_msg_pin_handle_size(struct dpll_pin *pin)
+{
+    return pin ? nla_total_size(4) : 0; /* DPLL_A_PIN_ID */
+}
+EXPORT_SYMBOL_GPL(dpll_msg_pin_handle_size);
+
  /**
   * dpll_msg_add_pin_handle - attach pin handle attribute to a given 
message
   * @msg: pointer to sk_buff message to attach a pin handle

@@ -54,6 +66,7 @@ int dpll_msg_add_pin_handle(struct sk_buff *msg, 

struct dpll_pin *pin)
          return -EMSGSIZE;
      return 0;
  }
+EXPORT_SYMBOL_GPL(dpll_msg_add_pin_handle);

Jiri, could you please remind me what is the reason to export this 
function? Because I cannot
any usage of this function in drivers.

Ah, found it, sorry for the noise.

[....]

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