[dpdk-dev] [PATCH v5 0/2] add uevent monitor for hot plug

[Jeff Guo]

So far, about hot plug in dpdk, we already have hot plug add/remove
api and fail-safe driver to offload the fail-safe work from the app
user. But there are still lack of a general event api, since the interrupt
event, which hot plug related with, is diversity between each device and
driver, such as mlx4, pci driver and others.

Use the hot removal event for example, pci drivers not all exposure the
remove interrupt, so in order to make user to easy use the hot plug feature
for pci driver, something must be done to detect the remove event at the
kernel level and offer a new line of interrupt to the user land.

Base on the uevent of kobject mechanism in kernel, we could use it to
benefit for monitoring the hot plug status of the device which not only
uio/vfio of pci bus devices, but also other, such as cpu/usb/pci-express
bus devices.

The idea is comming as bellow.

a.The uevent message form FD monitoring which will be useful.
remove@/devices/pci0000:80/0000:80:02.2/0000:82:00.0/0000:83:03.0/0000:84:00.2/uio/uio2
ACTION=remove
DEVPATH=/devices/pci0000:80/0000:80:02.2/0000:82:00.0/0000:83:03.0/0000:84:00.2/uio/uio2
SUBSYSTEM=uio
MAJOR=243
MINOR=2
DEVNAME=uio2
SEQNUM=11366

b.add uevent monitoring machanism:
add several general api to enable uevent monitoring.

c.add common uevent handler and uevent failure handler
uevent of device should be handler at bus or device layer, and the memory read
and write failure when hot removal should be handle correctly before detach behaviors.

d.show example how to use uevent monitor
enable uevent monitoring in testpmd or fail-safe to show usage.

patchset history:
v5->v4:
1.Move uevent monitor epolling from eal interrupt to eal device layer.
2.Redefine the eal device API for common, and distinguish between linux and bsd
3.Add failure handler helper api in bus layer.Add function of find device by name.
4.Replace of individual fd bind with single device, use a common fd to polling all device.
5.Add to register hot insertion monitoring and process, add function to auto bind driver befor user add device
6.Refine some coding style and typos issue
7.add new callback to process hot insertion

v4->v3:
1.move uevent monitor api from eal interrupt to eal device layer.
2.create uevent type and struct in eal device.
3.move uevent handler for each driver to eal layer.
4.add uevent failure handler to process signal fault issue.
5.add example for request and use uevent monitoring in testpmd.

v3->v2:
1.refine some return error
2.refine the string searching logic to avoid memory issue

v2->v1:
1.remove global variables of hotplug_fd, add uevent_fd
in rte_intr_handle to let each pci device self maintain it fd,
to fix dual device fd issue.
2.refine some typo error.


Jeff Guo (2):
  eal: add uevent monitor for hot plug
  app/testpmd: use uevent to monitor hot removal

 app/test-pmd/testpmd.c                             |  90 ++++++
 lib/librte_eal/bsdapp/eal/eal_dev.c                |  64 ++++
 .../bsdapp/eal/include/exec-env/rte_dev.h          | 105 ++++++
 lib/librte_eal/common/eal_common_bus.c             |  31 ++
 lib/librte_eal/common/eal_common_dev.c             | 223 ++++++++++++-
 lib/librte_eal/common/eal_common_pci.c             |  69 +++-
 lib/librte_eal/common/eal_common_pci_uio.c         |  31 +-
 lib/librte_eal/common/eal_common_vdev.c            |  29 +-
 lib/librte_eal/common/eal_private.h                |  13 +-
 lib/librte_eal/common/include/rte_bus.h            |  52 +++
 lib/librte_eal/common/include/rte_dev.h            | 102 +++++-
 lib/librte_eal/common/include/rte_pci.h            |  26 ++
 lib/librte_eal/linuxapp/eal/Makefile               |   3 +-
 lib/librte_eal/linuxapp/eal/eal_dev.c              | 351 +++++++++++++++++++++
 lib/librte_eal/linuxapp/eal/eal_pci.c              |  33 ++
 .../linuxapp/eal/include/exec-env/rte_dev.h        | 105 ++++++
 16 files changed, 1318 insertions(+), 9 deletions(-)
 create mode 100644 lib/librte_eal/bsdapp/eal/eal_dev.c
 create mode 100644 lib/librte_eal/bsdapp/eal/include/exec-env/rte_dev.h
 create mode 100644 lib/librte_eal/linuxapp/eal/eal_dev.c
 create mode 100644 lib/librte_eal/linuxapp/eal/include/exec-env/rte_dev.h

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2.7.4