| Message ID | 1649294865-4388-1-git-send-email-quic_linyyuan@quicinc.com |
|---|---|
| Headers | show |
| Series | usb: gadget: configfs: new trace events | expand |
On Thu, Apr 07, 2022 at 09:27:40AM +0800, Linyu Yuan wrote: > 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. But why? Who will use this, and what for? > 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. As userspace is the thing doing this, why do you need to tell userspace again that this happened? > 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 I said in other places, why not just add this to configfs directly instead of all over the individual users of this one subsystem? And again, why? thanks, greg k-h
> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Sent: Friday, April 22, 2022 8:17 PM > To: Linyu Yuan (QUIC) <quic_linyyuan@quicinc.com> > Cc: Felipe Balbi <balbi@kernel.org>; linux-usb@vger.kernel.org; Jack Pham > (QUIC) <quic_jackp@quicinc.com> > Subject: Re: [PATCH v6 0/5] usb: gadget: configfs: new trace events > > On Fri, Apr 22, 2022 at 09:01:13AM +0000, Linyu Yuan (QUIC) wrote: > > > From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > > Sent: Friday, April 22, 2022 4:43 PM > > > To: Linyu Yuan (QUIC) <quic_linyyuan@quicinc.com> > > > Cc: Felipe Balbi <balbi@kernel.org>; linux-usb@vger.kernel.org; Jack > Pham > > > (QUIC) <quic_jackp@quicinc.com> > > > Subject: Re: [PATCH v6 0/5] usb: gadget: configfs: new trace events > > > > > > On Thu, Apr 07, 2022 at 09:27:40AM +0800, Linyu Yuan wrote: > > > > 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. > > > > > > But why? Who will use this, and what for? > > > > Thanks for review it. > > It is not used by user space, just for kernel gadget issue debugging. > > So you use it in userspace? How can you use a tracepoint from somewhere > else in the kernel? > > > Like android, the user space is complicate to kernel developers, > > With this trace events, kernel development will understand > > What is simplified action happen from user space. > > They do not need this, they can just use ftrace today. Most of these > tracepoints you are putting in here are just for a "got to this > function!" type of thing, which ftrace can show you already. > > What is the added benefit of these over ftrace? Thanks, please discard this changes, will use kprobe event. > > thanks, > > greg k-h
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 V3: add trace.c and move all APIs to it v4: fix memory leak in v3 v5: change return value report by kernel test robot <lkp@intel.com> and Dan Carpenter <dan.carpenter@oracle.com> v6: fix checkpatch warning Linyu Yuan (5): usb: gadget: remove gadgets_type storage type 'static' 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 | 2 + drivers/usb/gadget/configfs.c | 45 ++++++- 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.c | 163 +++++++++++++++++++++++++ drivers/usb/gadget/trace.h | 39 ++++++ include/linux/usb/composite.h | 18 +++ include/linux/usb/gadget_configfs.h | 4 + 19 files changed, 396 insertions(+), 1 deletion(-) create mode 100644 drivers/usb/gadget/trace.c create mode 100644 drivers/usb/gadget/trace.h