Messages in this thread | | | Date | Wed, 23 Nov 2022 13:10:26 +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 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?
> >> >> >+ >> >+ 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.
> >> >+ if (err) >> >+ goto err_cancel_msg; >> >+ } >> >+ >> > genlmsg_end(msg, hdr); >> > return 0; >> > >> >-- >> >2.37.4 >> >
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