Re: [dpdk-dev] [PATCH v9 00/25] Introducing rte_driver/rte_device generalization

[Stephen Hemminger <stephen@networkplumber.org>]

On Wed, 7 Sep 2016 19:37:52 +0530
Shreyansh Jain <shreyansh.jain@nxp.com> wrote:

> Based on master (e22856313)
> 
> Background:
> ===========
> 
> It includes two different patch-sets floated on ML earlier:
>  * Original patch series is from David Marchand [1], [2].
>   `- This focused mainly on PCI (PDEV) part
>   `- v7 of this was posted by me [8] in August/2016
>  * Patch series [4] from Jan Viktorin
>   `- This focused on VDEV and rte_device integration
> 
> Introduction:
> =============
> 
> This patch series introduces a generic device model, moving away from PCI 
> centric code layout. Key change is to introduce rte_driver/rte_device 
> structures at the top level which are inherited by 
> rte_XXX_driver/rte_XXX_device - where XXX belongs to {pci, vdev, soc (in 
> future),...}.
> 
> Key motivation for this series is to move away from PCI centric design of 
> EAL to a more hierarchical device model - pivoted around a generic driver 
> and device. Each specific driver and device can inherit the common 
> properties of the generic set and build upon it through driver/device 
> specific functions.
> 
> Earlier, the EAL device initialization model was:
> (Refer: [3])
> 
> --
>  Constructor:
>   |- PMD_DRIVER_REGISTER(rte_driver)
>      `-  insert into dev_driver_list, rte_driver object
> 
>  rte_eal_init():
>   |- rte_eal_pci_init()
>   |  `- scan and fill pci_device_list from sysfs
>   |
>   |- rte_eal_dev_init()
>   |  `- For each rte_driver in dev_driver_list
>   |     `- call the rte_driver->init() function
>   |        |- PMDs designed to call rte_eth_driver_register(eth_driver)
>   |        |- eth_driver have rte_pci_driver embedded in them
>   |        `- rte_eth_driver_register installs the 
>   |           rte_pci_driver->devinit/devuninit callbacks.
>   |
>   |- rte_eal_pci_probe()
>   |  |- For each device detected, dev_driver_list is parsed and matching is
>   |  |  done.
>   |  |- For each matching device, the rte_pci_driver->devinit() is called.
>   |  |- Default map is to rte_eth_dev_init() which in turn creates a
>   |  |  new ethernet device (eth_dev)
>   |  |  `- eth_drv->eth_dev_init() is called which is implemented by 
>   `--|    individual PMD drivers.
> 
> --
> 
> The structure of driver looks something like:
> 
>  +------------+     ._____.
>  | rte_driver <-----| PMD |___
>  |  .init     |     `-----`   \
>  +----.-------+      |         \
>       `-.            |         What PMD actually is
>          \           |          |
>           +----------v----+     |
>           | eth_driver    |     |
>           | .eth_dev_init |     |
>           +----.----------+     |
>                `-.              |
>                   \             |
>                    +------------v---+
>                    | rte_pci_driver |
>                    | .pci_devinit   |
>                    +----------------+
> 
>   and all devices are part of a following linked lists:
>     - dev_driver_list for all rte_drivers
>     - pci_device_list for all devices, whether PCI or VDEV
> 
> 
> From the above:
>  * a PMD initializes a rte_driver, eth_driver even though actually it is a 
>    pci_driver
>  * initialization routines are passed from rte_driver->pci_driver->eth_driver
>    even though they should ideally be rte_eal_init()->rte_pci_driver()
>  * For a single driver/device type model, this is not necessarily a
>    functional issue - but more of a design language.
>  * But, when number of driver/device type increase, this would create problem
>    in how driver<=>device links are represented.
> 
> Proposed Architecture:
> ======================
> 
> A nice representation has already been created by David in [3]. Copying that
> here:
> 
>                 +------------------+ +-------------------------------+
>                 |                  | |                               |
>                 | rte_pci_device   | | rte_pci_driver                |
>                 |                  | |                               |
> +-------------+ | +--------------+ | | +---------------------------+ |
> |             | | |              | | | |                           | |
> | rte_eth_dev +---> rte_device   +-----> rte_driver                | |
> |             | | |  char name[] | | | |  char name[]              | |
> +-------------+ | |              | | | |  int init(rte_device *)   | |
>                 | +--------------+ | | |  int uninit(rte_device *) | |
>                 |                  | | |                           | |
>                 +------------------+ | +---------------------------+ |
>                                      |                               |
>                                      +-------------------------------+
> 
> - for ethdev on top of vdev devices
> 
>                 +------------------+ +-------------------------------+
>                 |                  | |                               |
>                 | drv specific     | | rte_vdev_driver               |
>                 |                  | |                               |
> +-------------+ | +--------------+ | | +---------------------------+ |
> |             | | |              | | | |                           | |
> | rte_eth_dev +---> rte_device   +-----> rte_driver                | |
> |             | | |  char name[] | | | |  char name[]              | |
> +-------------+ | |              | | | |  int init(rte_device *)   | |
>                 | +--------------+ | | |  int uninit(rte_device *) | |
>                 |                  | | |                           | |
>                 +------------------+ | +---------------------------+ |
>                                      |                               |
>                                      |   int priv_size               |
>                                      |                               |
>                                      +-------------------------------+
> 
> Representing from above, it would be:
> 
> +--------------+
> | rte_driver   |
> |  name        |
> |  <Future>    |
> +------^-------+      pci_driver_list
>        |                   /                vdev_driver_list
>        `---. <<Inherits>> /                  /
>            |\____________/_______           /
>            |            /        \         /
>            +-----------/-----+   +--------/---------+
>            | rte_pci_driver  |   | rte_vdev_driver  |
>            |  pci_devinit()  |   |  vdev_devinit()  |
>            |  pci_devuninit()|   |  vdev_devuninit()|
>            |  <more>         |   |  <more>          |
>            +-----------------+   +------------------+
> 
> 
> +--------------+
> | rte_device   |
> |  name        |
> |  <Future>    |
> +------^-------+        pci_device_list
>        |                   /               xxx_device_list
>        `---. <<Inherits>> /                  /
>            |\____________/________          /
>            |            /         \        /
>            +-----------/-----+   +--------/---------+
>            | rte_pci_device  |   | rte_xxx_device   |
>            |  <dev data>     |   |  <dev data>      |
>            |  <flags/intr>   |   |  <flags/intr>    |
>            |  <more>         |   |  <more>          |
>            +-----------------+   +------------------+
> 
>  * Each driver type has its own structure which derives from the generic 
>    rte_driver structure.
>    \- Each driver type maintains its own list, at the same time, rte_driver
>       list also exists - so that *all* drivers can be looped on, if required.
>  * Each device, associated with one or more drivers, has its own type
>    derived from rte_device
>    \- Each device _may_ maintain its own list (for example, in current 
>       implementation, vdev is not maintaining it).
> 
> ==Introducing a new device/driver type implies==
>   - creating their own rte_<xxx>.h file which contains the device/driver
>     definitions.
>   - defining the DRIVER_REGISTER_XXX helpers
> 
> ==Hotplugging Support==
>   - devices should be able to support attach/detach operations.
>   - Earlier these functions were part of ethdev. They have been moved to eal
>     to be more generic.
> 
>  This patch is part of larger aim to:
> 
>  --------------------+ <is type of>
>  eth_driver (PMD)    |-------------> rte_driver
>  crypto_driver (PMD) |               ^
>  <more in future>    |               |
>  --------------------+               | <inherits>
>                                     /
>            +-----------------------/+
>            | rte_pci_driver         |
>            | rte_vdev_driver        |
>            | rte_soc_driver         |
>            | rte_xxx_driver         |
> 
>  Where PMD devices (rte_eth_dev, rte_cryptodev_dev) are connected to their
>  drivers rather than explicitly inheriting type specific driver (PCI, etc).
> 
> 
> About the Patches:
> ==================
> 
> There are a large number of patches for this - primarily because the changes 
> are quite varied and keeping them logically separate yet compilable is
> important. Most of the patches are small and those which are large touch the
> drivers (PMDs) to accommodate the structure changes:
> 
>  - Patches 0001~0003 are for introducing the container_of function (so that 
>    rte_device can be obtained from rte_pci_device, for example), and 
>    removing unused code.
>  - Patches 0004~0007 just perform the ground work for enabling change from
>    rte_driver/eth_driver based PMDs to rte_xxx_driver based PMDs
>  - In patch 0008, all the pdev PMDs are changed to support rte_pci_driver (
>    including cryptodev, which is eventually generalized with PCI)
>  - Patch 0009~0010 merge the crypto and pci functions for registration and 
>    naming.
>  - Patches 0011~0014 deal with hotplugging - hotplug no more invokes scan of 
>    complete bus and has been generalized into EAl from ethdev.
>  - Patches 0015 introduces vdev init/uninit into separate C units and 
>    enables its compilation. Patch 0016~0017 build on it and remove the 
>    remaining legacy support for vdev/pdev distinctions.
>  - Patches 0018~0022 enable the vdev drivers to register using the 
>    DRIVER_REGISTER_* operations, and remove their rte_driver->init()
>  - Patch 0023 enables the rte_driver registration into a common driver
>    linked list.
>  - Patches 0024~0025 introduce the rte_device, a generalization of 
>    rte_xxx_device, and associated operation of creating rte_device linked 
>    list. It also enables the drivers to use rte_device.name/numa_node 
>    members rather than rte_xxx_device specific members.
> 
> Notes:
> ======
> 
> * Some sign-off were already provided by Jan on the original v5; But, as a 
>   large number of merges have been made, I am leaving those out just in case 
>   it is not sync with initial understanding.
> 
> * This might not be in-sync with pmdinfogen as PMD_REGISTER_DRIVER is
>   removed [7].
> 
> Future Work/Pending:
> ===================
>  - Presently eth_driver, rte_eth_dev are not aligned to the rte_driver/
>    rte_device model. eth_driver still is a PCI specific entity. This
>    has been highlighted by comments from Ferruh in [9].
>  - cryptodev driver too still remains to be normalized over the rte_driver
>    model
>  - Some variables, like drv_name (as highlighted by Ferruh), are getting
>    duplicated across rte_xxx_driver/device and rte_driver/device.
> 
> References:
> ===========
> 
> [1] http://dpdk.org/ml/archives/dev/2016-January/032387.html
> [2] http://dpdk.org/ml/archives/dev/2016-April/037686.html
> [3] http://dpdk.org/ml/archives/dev/2016-January/031390.html
> [4] http://dpdk.org/ml/archives/dev/2016-July/043645.html
> [5] http://dpdk.org/ml/archives/dev/2016-June/042439.html
> [6] http://dpdk.org/ml/archives/dev/2016-June/042444.html
> [7] http://dpdk.org/ml/archives/dev/2016-July/043172.html
> [8] http://dpdk.org/ml/archives/dev/2016-August/044941.html
> [9] http://dpdk.org/ml/archives/dev/2016-August/045947.html
> 
> Changes since v8:
> - Some review comments from Ferruh Yigit & Reshma Pattan have been fixed.
>  = Though changes in mlx4/mlx5/szedata2 have been done, I am still unable to
>    verify those in absence of a proper environment at my end.
>  = Comment from Ferruh for eth_driver, drv_name are not fixed yet.
> - Added a 'Future work' section in Covering letter
> 
> Changes since v7:
> - Rebase over master (e22856313fff2)
> - Merge the patch series by David [1][2] and Jan [4] into a single set
>   hereafter, PCI and VDEV, both are re-factored for rte_device/driver model
> 
> Changes since v6:
> - rebase over 16.07 (b0a1419)
> - DRIVER_REGISTER_PCI macro is now passed pci_drv rather than drv
> - review comments regarding missing information in log messages
> - new API additions to 16.11 map objects
> - review comment in [5] and [7] are not included in this series.
> 
> Changes since v5:
> - Rebase over master (11c5e45d8)
> - Rename RTE_EAL_PCI_REGISTER helper macro to DRIVER_REGISTER_PCI to be in 
>   sync
>   with DRIVER_REGISTER_PCI_TABLE. [Probably, in future, both can be merged]
> - Modifications to bnxt and thunderx driver PMD registration files for
>   using the simplified PCI device registration helper macro
> 
> Changes since v4:
> - Fix compilation issue after rebase on HEAD (913154e) in previous series
> - Retain rte_eth_dev_get_port_by_name and rte_eth_dev_get_name_by_port which
>   were removed by previous patchset. These are being used by pdump library
> 
> Changes since v3:
> - rebase over HEAD (913154e)
> - Update arguments to RTE_EAL_PCI_REGISTER macro as per Jan's suggestion
> - modify qede driver to use RTE_EAL_PCI_REGISTER
> - Argument check in hotplug functions
> 
> Changes since v2:
> - rebase over HEAD (d76c193)
> - Move SYSFS_PCI_DRIVERS macro to rte_pci.h to avoid compilation issue
> 
> Changes since v1:
> - rebased on HEAD, new drivers should be okay
> - patches have been split into smaller pieces
> - RTE_INIT macro has been added, but in the end, I am not sure it is useful
> - device type has been removed from ethdev, as it was used only by hotplug
> - getting rid of pmd type in eal patch (patch 5 of initial series) has been
>   dropped for now, we can do this once vdev drivers have been converted
> 
> 
> Shreyansh Jain (25):
>   eal: define macro container_of
>   eal: remove duplicate function declaration
>   pci: no need for dynamic tailq init
>   crypto: no need for a crypto pmd type
>   drivers: align pci driver definitions
>   eal: introduce init macros
>   driver: init/uninit common wrappers for PCI drivers
>   drivers: convert all pdev drivers as pci drivers
>   driver: Remove driver register callbacks for crypto/net
>   eal/pci: Helpers for device name parsing/update
>   ethdev: do not scan all pci devices on attach
>   eal: add hotplug operations for pci and vdev
>   ethdev: convert to eal hotplug
>   ethdev: get rid of device type
>   eal: extract vdev infra
>   eal: Remove PDEV/VDEV unused code
>   drivers: convert PMD_VDEV drivers to use rte_vdev_driver
>   eal: move init/uninit to rte_vdev_driver
>   eal: remove PMD_DRIVER_REGISTER and unused pmd_types
>   eal: rte_pci.h includes rte_dev.h
>   eal: rename and move rte_pci_resource
>   eal/pci: inherit rte_driver by rte_pci_driver
>   eal: call rte_eal_driver_register
>   eal: introduce rte_device
>   eal/pci: Create rte_device list and fallback on its members
> 
>  app/test/test_pci.c                             |  10 +-
>  app/test/virtual_pmd.c                          |   8 +-
>  drivers/crypto/aesni_gcm/aesni_gcm_pmd.c        |   7 +-
>  drivers/crypto/aesni_mb/rte_aesni_mb_pmd.c      |   7 +-
>  drivers/crypto/kasumi/rte_kasumi_pmd.c          |   7 +-
>  drivers/crypto/null/null_crypto_pmd.c           |   7 +-
>  drivers/crypto/qat/qat_qp.c                     |   2 +-
>  drivers/crypto/qat/rte_qat_cryptodev.c          |  18 +-
>  drivers/crypto/snow3g/rte_snow3g_pmd.c          |   7 +-
>  drivers/net/af_packet/rte_eth_af_packet.c       |  11 +-
>  drivers/net/bnx2x/bnx2x_ethdev.c                |  36 +--
>  drivers/net/bnx2x/bnx2x_rxtx.c                  |   3 +-
>  drivers/net/bnxt/bnxt_ethdev.c                  |  17 +-
>  drivers/net/bonding/rte_eth_bond_api.c          |   2 +-
>  drivers/net/bonding/rte_eth_bond_pmd.c          |   9 +-
>  drivers/net/cxgbe/cxgbe_ethdev.c                |  25 +--
>  drivers/net/cxgbe/cxgbe_main.c                  |   2 +-
>  drivers/net/cxgbe/sge.c                         |   7 +-
>  drivers/net/e1000/em_ethdev.c                   |  17 +-
>  drivers/net/e1000/igb_ethdev.c                  |  41 +---
>  drivers/net/ena/ena_ethdev.c                    |  20 +-
>  drivers/net/enic/enic_ethdev.c                  |  24 +-
>  drivers/net/fm10k/fm10k_ethdev.c                |  30 +--
>  drivers/net/i40e/i40e_ethdev.c                  |  31 +--
>  drivers/net/i40e/i40e_ethdev_vf.c               |  26 +--
>  drivers/net/i40e/i40e_fdir.c                    |   2 +-
>  drivers/net/ixgbe/ixgbe_ethdev.c                |  48 +---
>  drivers/net/mlx4/mlx4.c                         |  21 +-
>  drivers/net/mlx5/mlx5.c                         |  22 +-
>  drivers/net/mpipe/mpipe_tilegx.c                |  18 +-
>  drivers/net/nfp/nfp_net.c                       |  28 +--
>  drivers/net/null/rte_eth_null.c                 |  11 +-
>  drivers/net/pcap/rte_eth_pcap.c                 |  11 +-
>  drivers/net/qede/qede_ethdev.c                  |  42 +---
>  drivers/net/ring/rte_eth_ring.c                 |  11 +-
>  drivers/net/szedata2/rte_eth_szedata2.c         |  29 +--
>  drivers/net/thunderx/nicvf_ethdev.c             |  21 +-
>  drivers/net/vhost/rte_eth_vhost.c               |  11 +-
>  drivers/net/virtio/virtio_ethdev.c              |  28 +--
>  drivers/net/virtio/virtio_pci.c                 |   5 +-
>  drivers/net/virtio/virtio_user_ethdev.c         |  10 +-
>  drivers/net/vmxnet3/vmxnet3_ethdev.c            |  27 +--
>  drivers/net/vmxnet3/vmxnet3_rxtx.c              |   2 +-
>  drivers/net/xenvirt/rte_eth_xenvirt.c           |  11 +-
>  examples/ip_pipeline/init.c                     |  22 --
>  lib/librte_cryptodev/rte_cryptodev.c            |  71 ++----
>  lib/librte_cryptodev/rte_cryptodev.h            |   2 -
>  lib/librte_cryptodev/rte_cryptodev_pmd.h        |  45 ++--
>  lib/librte_cryptodev/rte_cryptodev_version.map  |   8 +-
>  lib/librte_eal/bsdapp/eal/Makefile              |   1 +
>  lib/librte_eal/bsdapp/eal/eal_pci.c             |  54 ++++-
>  lib/librte_eal/bsdapp/eal/rte_eal_version.map   |   7 +
>  lib/librte_eal/common/Makefile                  |   2 +-
>  lib/librte_eal/common/eal_common_dev.c          |  95 ++++----
>  lib/librte_eal/common/eal_common_pci.c          |  34 ++-
>  lib/librte_eal/common/eal_common_vdev.c         | 106 +++++++++
>  lib/librte_eal/common/eal_private.h             |  20 +-
>  lib/librte_eal/common/include/rte_common.h      |  21 ++
>  lib/librte_eal/common/include/rte_dev.h         |  77 +++++--
>  lib/librte_eal/common/include/rte_eal.h         |   3 +
>  lib/librte_eal/common/include/rte_pci.h         |  51 +++--
>  lib/librte_eal/common/include/rte_tailq.h       |   4 +-
>  lib/librte_eal/common/include/rte_vdev.h        |  96 ++++++++
>  lib/librte_eal/linuxapp/eal/Makefile            |   1 +
>  lib/librte_eal/linuxapp/eal/eal.c               |   1 +
>  lib/librte_eal/linuxapp/eal/eal_pci.c           |  23 +-
>  lib/librte_eal/linuxapp/eal/rte_eal_version.map |  10 +
>  lib/librte_ether/rte_ethdev.c                   | 280 +++++-------------------
>  lib/librte_ether/rte_ethdev.h                   |  40 ++--
>  lib/librte_ether/rte_ether_version.map          |  10 +-
>  70 files changed, 791 insertions(+), 1025 deletions(-)
>  create mode 100644 lib/librte_eal/common/eal_common_vdev.c
>  create mode 100644 lib/librte_eal/common/include/rte_vdev.h
> 

Overall I like to see the clean separation.
Are you sure you removed as much as possible from PCI?
I wonder of global PCI device list is needed at all if you now have list of all devices.