[v5] ethtool: doc: clarify what drivers can implement in their get_drvinfo()
Commit Message
Many of the drivers which implement ethtool_ops::get_drvinfo() will
prints the .driver, .version or .bus_info of struct ethtool_drvinfo.
To have a glance of current state, do:
$ git grep -W "get_drvinfo(struct"
Printing in those three fields is useless because:
- since [1], the driver version should be the kernel version (at
least for upstream drivers). Arguably, out of tree drivers might
still want to set a custom version, but out of tree is not our
focus.
- since [2], the core is able to provide default values for .driver
and .bus_info.
In summary, drivers may provide .fw_version and .erom_version, the
rest is expected to be done by the core.
In struct ethtool_ops doc from linux/ethtool: rephrase field
get_drvinfo() doc to discourage developers from implementing this
callback.
In struct ethtool_drvinfo doc from uapi/linux/ethtool.h: remove the
paragraph mentioning what drivers should do. Rationale: no need to
repeat what is already written in struct ethtool_ops doc. But add a
note that .fw_version and .erom_version are driver defined.
Also update the dummy driver and simply remove the callback in order
not to confuse the newcomers: most of the drivers will not need this
callback function any more.
[1] commit 6a7e25c7fb48 ("net/core: Replace driver version to be
kernel version")
Link: https://git.kernel.org/torvalds/linux/c/6a7e25c7fb48
[2] commit edaf5df22cb8 ("ethtool: ethtool_get_drvinfo: populate
drvinfo fields even if callback exits")
Link: https://git.kernel.org/netdev/net-next/c/edaf5df22cb8
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
* Changelog *
v4 -> v5:
* update struct ethtool_drvinfo doc in uapi/linux/ethtool.h as well.
* remove the paragraph mentioning what drivers should do from struct
ethtool_drvinfo in uapi/linux/ethtool.h. Rationale: no need to
repeat what is already written in struct ethtool_ops doc.
v3 -> v4:
* rephrasing of the documentation according to Jakub's comments.
v2 -> v3:
* add Reviewed-by: Leon Romanovsky <leonro@nvidia.com> tag.
* use shorter links.
v1 -> v2:
* forgot the net-next prefix in the patch subject... Sorry for the
noise.
---
drivers/net/dummy.c | 7 -------
include/linux/ethtool.h | 8 ++++----
include/uapi/linux/ethtool.h | 10 ++++------
3 files changed, 8 insertions(+), 17 deletions(-)
Comments
Hello:
This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:
On Thu, 17 Nov 2022 02:18:28 +0900 you wrote:
> Many of the drivers which implement ethtool_ops::get_drvinfo() will
> prints the .driver, .version or .bus_info of struct ethtool_drvinfo.
> To have a glance of current state, do:
>
> $ git grep -W "get_drvinfo(struct"
>
> Printing in those three fields is useless because:
>
> [...]
Here is the summary with links:
- [v5] ethtool: doc: clarify what drivers can implement in their get_drvinfo()
https://git.kernel.org/netdev/net-next/c/f20a0a0519f3
You are awesome, thank you!
@@ -99,14 +99,7 @@ static const struct net_device_ops dummy_netdev_ops = {
.ndo_change_carrier = dummy_change_carrier,
};
-static void dummy_get_drvinfo(struct net_device *dev,
- struct ethtool_drvinfo *info)
-{
- strscpy(info->driver, DRV_NAME, sizeof(info->driver));
-}
-
static const struct ethtool_ops dummy_ethtool_ops = {
- .get_drvinfo = dummy_get_drvinfo,
.get_ts_info = ethtool_op_get_ts_info,
};
@@ -473,10 +473,10 @@ struct ethtool_module_power_mode_params {
* parameter.
* @supported_coalesce_params: supported types of interrupt coalescing.
* @supported_ring_params: supported ring params.
- * @get_drvinfo: Report driver/device information. Should only set the
- * @driver, @version, @fw_version and @bus_info fields. If not
- * implemented, the @driver and @bus_info fields will be filled in
- * according to the netdev's parent device.
+ * @get_drvinfo: Report driver/device information. Modern drivers no
+ * longer have to implement this callback. Most fields are
+ * correctly filled in by the core using system information, or
+ * populated using other driver operations.
* @get_regs_len: Get buffer length required for @get_regs
* @get_regs: Get device registers
* @get_wol: Report whether Wake-on-Lan is enabled
@@ -159,8 +159,10 @@ static inline __u32 ethtool_cmd_speed(const struct ethtool_cmd *ep)
* in its bus driver structure (e.g. pci_driver::name). Must
* not be an empty string.
* @version: Driver version string; may be an empty string
- * @fw_version: Firmware version string; may be an empty string
- * @erom_version: Expansion ROM version string; may be an empty string
+ * @fw_version: Firmware version string; driver defined; may be an
+ * empty string
+ * @erom_version: Expansion ROM version string; driver defined; may be
+ * an empty string
* @bus_info: Device bus address. This should match the dev_name()
* string for the underlying bus device, if there is one. May be
* an empty string.
@@ -179,10 +181,6 @@ static inline __u32 ethtool_cmd_speed(const struct ethtool_cmd *ep)
*
* Users can use the %ETHTOOL_GSSET_INFO command to get the number of
* strings in any string set (from Linux 2.6.34).
- *
- * Drivers should set at most @driver, @version, @fw_version and
- * @bus_info in their get_drvinfo() implementation. The ethtool
- * core fills in the other fields using other driver operations.
*/
struct ethtool_drvinfo {
__u32 cmd;