Messages in this thread | | | Date | Wed, 23 Nov 2022 17:26:42 +0100 | From | Jiri Pirko <> | Subject | Re: [RFC PATCH] net: devlink: devlink_nl_info_fill: populate default information |
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Wed, Nov 23, 2022 at 05:08:10PM CET, mailhol.vincent@wanadoo.fr wrote: >On Wed. 23 Nov. 2022 at 21:10, Jiri Pirko <jiri@nvidia.com> wrote: >> Wed, Nov 23, 2022 at 12:00:44PM CET, mailhol.vincent@wanadoo.fr wrote: >> >On Wed. 23 nov. 2022 à 18:46, Jiri Pirko <jiri@nvidia.com> wrote: >> >> Tue, Nov 22, 2022 at 04:49:34PM CET, mailhol.vincent@wanadoo.fr wrote: >> >> >Some piece of information are common to the vast majority of the >> >> >devices. Examples are: >> >> > >> >> > * the driver name. >> >> > * the serial number of a USB device. >> >> > >> >> >Modify devlink_nl_info_fill() to retrieve those information so that >> >> >the drivers do not have to. Rationale: factorize code. >> >> > >> >> >Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> >> >> >--- >> >> >I am sending this as an RFC because I just started to study devlink. >> >> > >> >> >I can see a parallel with ethtool for which the core will fill >> >> >whatever it can. c.f.: >> >> >commit f20a0a0519f3 ("ethtool: doc: clarify what drivers can implement in their get_drvinfo()") >> >> >Link: https://git.kernel.org/netdev/net-next/c/f20a0a0519f3 >> >> > >> >> >I think that devlink should do the same. >> >> > >> >> >Right now, I identified two fields. If this RFC receive positive >> >> >feedback, I will iron it up and try to see if there is more that can >> >> >be filled by default. >> >> > >> >> >Thank you for your comments. >> >> >--- >> >> > net/core/devlink.c | 36 ++++++++++++++++++++++++++++++++++++ >> >> > 1 file changed, 36 insertions(+) >> >> > >> >> >diff --git a/net/core/devlink.c b/net/core/devlink.c >> >> >index 7f789bbcbbd7..1908b360caf7 100644 >> >> >--- a/net/core/devlink.c >> >> >+++ b/net/core/devlink.c >> >> >@@ -18,6 +18,7 @@ >> >> > #include <linux/netdevice.h> >> >> > #include <linux/spinlock.h> >> >> > #include <linux/refcount.h> >> >> >+#include <linux/usb.h> >> >> > #include <linux/workqueue.h> >> >> > #include <linux/u64_stats_sync.h> >> >> > #include <linux/timekeeping.h> >> >> >@@ -6685,12 +6686,37 @@ int devlink_info_version_running_put_ext(struct devlink_info_req *req, >> >> > } >> >> > EXPORT_SYMBOL_GPL(devlink_info_version_running_put_ext); >> >> > >> >> >+static int devlink_nl_driver_info_get(struct device_driver *drv, >> >> >+ struct devlink_info_req *req) >> >> >+{ >> >> >+ if (!drv) >> >> >+ return 0; >> >> >+ >> >> >+ if (drv->name[0]) >> >> >+ return devlink_info_driver_name_put(req, drv->name); >> >> >> >> Make sure that this provides the same value for all existing drivers >> >> using devlink. >> > >> >There are 21 drivers so far which reports the driver name through devlink. c.f.: >> > $ git grep "devlink_info_driver_name_put(" drivers | wc -l >> > >> >Out of those 21, there is only one: the mlxsw which seems to report >> >something different than device_driver::name. Instead it reports some >> >bus_info: >> > https://elixir.bootlin.com/linux/v6.1-rc1/source/drivers/net/ethernet/mellanox/mlxsw/core.c#L1462 >> > https://elixir.bootlin.com/linux/v6.1-rc1/source/drivers/net/ethernet/mellanox/mlxsw/core.h#L504 >> > >> >I am not sure what the bus_info is here, but it looks like a misuse of >> >the field here. >> >> When you are not sure, look into the code to find out :) I see no misue. >> What exactly do you mean by that? > >I mean that device_kind, it does not sound like a field that would >hold the driver name. > >Looking deeper in the code, I got the confirmation. >bus_info::device_kind is initialized here (among other): >https://elixir.bootlin.com/linux/v6.1-rc1/source/drivers/net/ethernet/mellanox/mlxsw/i2c.c#L714 > >and it uses ic2_client::name which indicate the type of the device >(e.g. chip name): >https://elixir.bootlin.com/linux/v6.1-rc1/source/include/linux/i2c.h#L317 > >So I confirm that this is a misuse. This driver does not report the >driver's name.
Okay, I think that is a bug of mlxsw_i2c implementation. You can fix it along the way.
> >> >> >+ >> >> >+ return 0; >> >> >+} >> >> >+ >> >> >+static int devlink_nl_usb_info_get(struct usb_device *udev, >> >> >+ struct devlink_info_req *req) >> >> >+{ >> >> >+ if (!udev) >> >> >+ return 0; >> >> >+ >> >> >+ if (udev->serial[0]) >> >> >+ return devlink_info_serial_number_put(req, udev->serial); >> >> >+ >> >> >+ return 0; >> >> >+} >> >> >+ >> >> > static int >> >> > devlink_nl_info_fill(struct sk_buff *msg, struct devlink *devlink, >> >> > enum devlink_command cmd, u32 portid, >> >> > u32 seq, int flags, struct netlink_ext_ack *extack) >> >> > { >> >> > struct devlink_info_req req = {}; >> >> >+ struct device *dev = devlink_to_dev(devlink); >> >> > void *hdr; >> >> > int err; >> >> > >> >> >@@ -6707,6 +6733,16 @@ devlink_nl_info_fill(struct sk_buff *msg, struct devlink *devlink, >> >> > if (err) >> >> > goto err_cancel_msg; >> >> > >> >> >+ err = devlink_nl_driver_info_get(dev->driver, &req); >> >> >+ if (err) >> >> >+ goto err_cancel_msg; >> >> >+ >> >> >+ if (!strcmp(dev->parent->type->name, "usb_device")) { >> >> >> >> Comparing to string does not seem correct here. >> > >> >There is a is_usb_device() which does the check: >> > https://elixir.bootlin.com/linux/v6.1-rc1/source/drivers/usb/core/usb.h#L152 >> > >> >but this macro is not exposed outside of the usb core. The string >> >comparison was the only solution I found. >> >> Find a different one. String check here is wrong. >> > >> >Do you have any other ideas? If not and if this goes further than the >> >RFC stage, I will ask the USB folks if there is a better way. >> > >> >> >> >> >+ err = devlink_nl_usb_info_get(to_usb_device(dev->parent), &req); >> >> >> >> As Jakub pointed out, you have to make sure that driver does not put the >> >> same attrs again. You have to introduce this functionality with removing >> >> the fill-ups in drivers atomically, in a single patch. >> > >> >Either this, either track if the attribute is already set. I would >> >prefer to remove all drivers fill-ups but this is not feasible for the >> >serial number. c.f. my reply to Jacub in this thread: >> > https://lore.kernel.org/netdev/CAMZ6RqJ8_=h1SS7WmBeEB=75wsvVUZrb-8ELCDtpZb0gSs=2+A@mail.gmail.com/ >> >> Sure, but for the driver name it is. Let's start there. > >I will do a first patch only for the driver name and think again of >the USB serial later on.
Yep, thanks!
> > >Yours sincerely, >Vincent Mailhol
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