On Thu, Sep 06, 2018 at 05:51:12PM +0300, Arseny Maslennikov wrote: > Some tools may currently be using only the deprecated attribute; > let's print an elaborate and clear deprecation notice to kmsg. > > To do that, we have to replace the whole sysfs file, since we inherit > the original one from netdev. > > Signed-off-by: Arseny Maslennikov <ar@xxxxxxxxx> > drivers/infiniband/ulp/ipoib/ipoib_main.c | 31 +++++++++++++++++++++++ > 1 file changed, 31 insertions(+) > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c > index 30f840f874b3..74732726ec6f 100644 > +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c > @@ -2386,6 +2386,35 @@ int ipoib_add_pkey_attr(struct net_device *dev) > return device_create_file(&dev->dev, &dev_attr_pkey); > } > > +/* > + * We erroneously exposed the iface's port number in the dev_id > + * sysfs field long after dev_port was introduced for that purpose[1], > + * and we need to stop everyone from relying on that. > + * Let's overload the shower routine for the dev_id file here > + * to gently bring the issue up. > + * > + * [1] https://www.spinics.net/lists/netdev/msg272123.html > + */ > +static ssize_t dev_id_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct net_device *ndev = to_net_dev(dev); > + > + if (ndev->dev_id == ndev->dev_port) > + netdev_info_once(ndev, > + "\"%s\" wants to know my dev_id. Should it look at dev_port instead? See Documentation/ABI/testing/sysfs-class-net for more info.\n", > + current->comm); > + > + return sprintf(buf, "%#x\n", ndev->dev_id); > +} > +static DEVICE_ATTR_RO(dev_id); > + > +int ipoib_intercept_dev_id_attr(struct net_device *dev) > +{ > + device_remove_file(&dev->dev, &dev_attr_dev_id); > + return device_create_file(&dev->dev, &dev_attr_dev_id); > +} Isn't this racey with userspace? Ie what happens if udev is querying the dev_id right here? Do we know there is no userspace doing this? > static struct net_device *ipoib_add_port(const char *format, > struct ib_device *hca, u8 port) > { > @@ -2427,6 +2456,8 @@ static struct net_device *ipoib_add_port(const char *format, > */ > ndev->priv_destructor = ipoib_intf_free; > > + if (ipoib_intercept_dev_id_attr(ndev)) > + goto sysfs_failed; No device_remove_file needed? Jason
