Messages in this thread Patch in this message | | | From | Vincent MAILHOL <> | Date | Wed, 23 Nov 2022 20:00:44 +0900 | Subject | Re: [RFC PATCH] net: devlink: devlink_nl_info_fill: populate default information |
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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.
> > >+ > >+ 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.
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/ > >+ if (err) > >+ goto err_cancel_msg; > >+ } > >+ > > genlmsg_end(msg, hdr); > > return 0; > > > >-- > >2.37.4 > >
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