Hi Cornelia, > -----Original Message----- > From: Cornelia Huck <cohuck@xxxxxxxxxx> > Sent: Tuesday, September 17, 2019 5:14 AM > To: Parav Pandit <parav@xxxxxxxxxxxx> > Cc: alex.williamson@xxxxxxxxxx; Jiri Pirko <jiri@xxxxxxxxxxxx>; > kwankhede@xxxxxxxxxx; davem@xxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v3 0/5] Introduce variable length mdev alias > > On Sun, 1 Sep 2019 23:24:31 -0500 > Parav Pandit <parav@xxxxxxxxxxxx> wrote: > > > To have consistent naming for the netdevice of a mdev and to have > > consistent naming of the devlink port [1] of a mdev, which is formed > > using phys_port_name of the devlink port, current UUID is not usable > > because UUID is too long. > > > > UUID in string format is 36-characters long and in binary 128-bit. > > Both formats are not able to fit within 15 characters limit of netdev > > name. > > > > It is desired to have mdev device naming consistent using UUID. > > So that widely used user space framework such as ovs [2] can make use > > of mdev representor in similar way as PCIe SR-IOV VF and PF representors. > > > > Hence, > > (a) mdev alias is created which is derived using sha1 from the mdev name. > > (b) Vendor driver describes how long an alias should be for the child > > mdev created for a given parent. > > (c) Mdev aliases are unique at system level. > > (d) alias is created optionally whenever parent requested. > > This ensures that non networking mdev parents can function without > > alias creation overhead. > > > > This design is discussed at [3]. > > > > An example systemd/udev extension will have, > > > > 1. netdev name created using mdev alias available in sysfs. > > > > mdev UUID=83b8f4f2-509f-382f-3c1e-e6bfe0fa1001 > > mdev 12 character alias=cd5b146a80a5 > > > > netdev name of this mdev = enmcd5b146a80a5 Here en = Ethernet link m = > > mediated device > > > > 2. devlink port phys_port_name created using mdev alias. > > devlink phys_port_name=pcd5b146a80a5 > > > > This patchset enables mdev core to maintain unique alias for a mdev. > > > > Patch-1 Introduces mdev alias using sha1. > > Patch-2 Ensures that mdev alias is unique in a system. > > Patch-3 Exposes mdev alias in a sysfs hirerchy, update Documentation > > Patch-4 Introduces mdev_alias() API. > > Patch-5 Extends mtty driver to optionally provide alias generation. > > This also enables to test UUID based sha1 collision and trigger error > > handling for duplicate sha1 results. > > > > [1] http://man7.org/linux/man-pages/man8/devlink-port.8.html > > [2] https://docs.openstack.org/os-vif/latest/user/plugins/ovs.html > > [3] https://patchwork.kernel.org/cover/11084231/ > > > > --- > > Changelog: > > v2->v3: > > - Addressed comment from Yunsheng Lin > > - Changed strcmp() ==0 to !strcmp() > > - Addressed comment from Cornelia Hunk > > - Merged sysfs Documentation patch with syfs patch > > - Added more description for alias return value > > v1->v2: > > - Corrected a typo from 'and' to 'an' > > - Addressed comments from Alex Williamson > > - Kept mdev_device naturally aligned > > - Added error checking for crypt_*() calls > > - Moved alias NULL check at beginning > > - Added mdev_alias() API > > - Updated mtty driver to show example mdev_alias() usage > > - Changed return type of generate_alias() from int to char* > > v0->v1: > > - Addressed comments from Alex Williamson, Cornelia Hunk and Mark > > Bloch > > - Moved alias length check outside of the parent lock > > - Moved alias and digest allocation from kvzalloc to kzalloc > > - &alias[0] changed to alias > > - alias_length check is nested under get_alias_length callback check > > - Changed comments to start with an empty line > > - Added comment where alias memory ownership is handed over to mdev > > device > > - Fixed cleaunup of hash if mdev_bus_register() fails > > - Updated documentation for new sysfs alias file > > - Improved commit logs to make description more clear > > - Fixed inclusiong of alias for NULL check > > - Added ratelimited debug print for sha1 hash collision error > > > > Parav Pandit (5): > > mdev: Introduce sha1 based mdev alias > > mdev: Make mdev alias unique among all mdevs > > mdev: Expose mdev alias in sysfs tree > > mdev: Introduce an API mdev_alias > > mtty: Optionally support mtty alias > > > > .../driver-api/vfio-mediated-device.rst | 9 ++ > > drivers/vfio/mdev/mdev_core.c | 142 +++++++++++++++++- > > drivers/vfio/mdev/mdev_private.h | 5 +- > > drivers/vfio/mdev/mdev_sysfs.c | 26 +++- > > include/linux/mdev.h | 5 + > > samples/vfio-mdev/mtty.c | 13 ++ > > 6 files changed, 190 insertions(+), 10 deletions(-) > > > > The patches on their own look sane (and I gave my R-b), but the consumer of > this new API should be ready before this is merged, as already discussed below. Thanks for the review. I will send v4 here to address all comments and to add your R-b tag. I am waiting for Saeed to post other prep series of mlx5_core to be merged before I post actual consumer series, as it depends on it. I will also drop the mtty sample patch and change-log to avoid confusion with versions when I combine them with consumer series.
