[v2,0/4] usb: gadget: configfs: new trace events

Last year I try to add trace event support for usb gadget configfs [1],
this time the idea is change a lot, the purpose is trace all user space
operation to gadget configuration, include gadget and it's function.

In usb gadget configfs, mainly user can do mkdir/rmdir a group,
link/unlink a function, change gadget/function attributes,
each operation will touch a struct config_item.

It only have one trace event entry which store string,
provide several API which represent user operation and generate string
from  struct config_item.

example output,
   mkdir-80      [000] .....    44.555106: gadget_configfs: mkdir dummy
      sh-76      [000] .....    44.562609: gadget_configfs: echo dummy/idVendor 0x05C6

   mkdir-81      [000] .....    44.569795: gadget_configfs: mkdir dummy/functions/eem.0
      sh-76      [000] .....    44.600221: gadget_configfs: echo dummy/functions/eem.0/dev_addr 1e:77:46:4b:1e:96

   mkdir-82      [000] .....    44.615542: gadget_configfs: mkdir dummy/configs/dummy.1
      ln-83      [000] .....    44.628997: gadget_configfs: link dummy/configs/dummy.1 dummy/functions/eem.0
      sh-76      [000] .....    44.634506: gadget_configfs: echo dummy/configs/dummy.1/MaxPower 500

   mkdir-84      [000] .....    44.642265: gadget_configfs: mkdir dummy/configs/dummy.1/strings/0x409
      sh-76      [000] .....    44.663886: gadget_configfs: echo dummy/configs/dummy.1/strings/0x409/configuration dummy

   rmdir-85      [000] .....    64.255507: gadget_configfs: rmdir dummy/configs/dummy.1/strings/0x409
      rm-86      [000] .....    64.263926: gadget_configfs: unlink dummy/configs/dummy.1 dummy/functions/eem.0
   rmdir-87      [000] .....    64.279768: gadget_configfs: rmdir dummy/configs/dummy.1
   rmdir-88      [000] .....    64.328124: gadget_configfs: rmdir dummy/functions/eem.0
   rmdir-89      [000] .....    64.992085: gadget_configfs: rmdir dummy


As it is different from last year change, start a new thread.

[1] https://lore.kernel.org/linux-usb/1635229309-2821-1-git-send-email-quic_linyyuan@quicinc.com/

V2: add example output

Linyu Yuan (4):
  usb: gadget: add trace event of configfs operation
  usb: gadget: add trace event of configfs group operation
  usb: gadget: add trace event of configfs link/unlink operation
  usb: gadget: add trace event of configfs write attributes operation

 drivers/usb/gadget/Makefile                    |   1 +
 drivers/usb/gadget/configfs.c                  | 188 +++++++++++++++++++++++++
 drivers/usb/gadget/function/f_acm.c            |   1 +
 drivers/usb/gadget/function/f_hid.c            |   4 +
 drivers/usb/gadget/function/f_loopback.c       |   4 +
 drivers/usb/gadget/function/f_mass_storage.c   |  20 +++
 drivers/usb/gadget/function/f_midi.c           |   6 +
 drivers/usb/gadget/function/f_printer.c        |   4 +
 drivers/usb/gadget/function/f_serial.c         |   1 +
 drivers/usb/gadget/function/f_sourcesink.c     |  16 +++
 drivers/usb/gadget/function/f_uac1.c           |   6 +
 drivers/usb/gadget/function/f_uac1_legacy.c    |   4 +
 drivers/usb/gadget/function/f_uac2.c           |   8 ++
 drivers/usb/gadget/function/u_ether_configfs.h |  10 ++
 drivers/usb/gadget/function/uvc_configfs.c     |  42 ++++++
 drivers/usb/gadget/trace.h                     |  39 +++++
 include/linux/usb/composite.h                  |  18 +++
 include/linux/usb/gadget_configfs.h            |   4 +
 18 files changed, 376 insertions(+)
 create mode 100644 drivers/usb/gadget/trace.h