Dear all,
1. Overview
In current USB/IP implementation, event kernel threads are created for
each port. The functions of the threads are closing connection and
error handling so they don't have not so many events to handle. There's
no need to have thread for each port.
BEFORE) vhci side - VHCI_NPORTS(8) threads are created.
$ ps aux | grep usbip
root 10059 0.0 0.0 0 0 ? S 17:06 0:00 [usbip_eh]
root 10060 0.0 0.0 0 0 ? S 17:06 0:00 [usbip_eh]
root 10061 0.0 0.0 0 0 ? S 17:06 0:00 [usbip_eh]
root 10062 0.0 0.0 0 0 ? S 17:06 0:00 [usbip_eh]
root 10063 0.0 0.0 0 0 ? S 17:06 0:00 [usbip_eh]
root 10064 0.0 0.0 0 0 ? S 17:06 0:00 [usbip_eh]
root 10065 0.0 0.0 0 0 ? S 17:06 0:00 [usbip_eh]
root 10066 0.0 0.0 0 0 ? S 17:06 0:00 [usbip_eh]
BEFORE) stub side - threads will be created every bind operation.
$ ps aux | grep usbip
root 8368 0.0 0.0 0 0 ? S 17:56 0:00 [usbip_eh]
root 8399 0.0 0.0 0 0 ? S 17:56 0:00 [usbip_eh]
This patch put event threads of stub and vhci driver as one workqueue.
AFTER) only one event threads in each vhci and stub side.
$ ps aux | grep usbip
root 10457 0.0 0.0 0 0 ? S< 17:47 0:00 [usbip_event]
2. Modification to usbip_event.c
BEFORE) kernel threads are created in usbip_start_eh().
AFTER) one workqueue is created in new usbip_init_eh().
Event handler which was main loop of kernel thread is modified to
workqueue handler.
Events themselves are stored in struct usbip_device - same as before.
usbip_devices which have event are listed in event_list.
The handler picks an element from the list and wakeup usbip_device. The
wakeup method is same as before.
usbip_in_eh() substitutes statement which checks whether functions are
called from eh_ops or not. In this function, the worker context is used
for the checking. The context will be set in a variable in the
beginning of first event handling. usbip_in_eh() is used in event
handler so it works well.
3. Modifications to programs using usbip_event.c
Initialization and termination of workqueue are added to init and exit
routine of usbip_core respectively.
A. version info
v2)
# Merged 1/2 event handler itself and 2/2 user programs because of auto
build fail at 1/2 casued unmodified user programs in 1/2.
Signed-off-by: Nobuo Iwata <nobuo.iwata@fujixerox.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
At this point, USB/IP kernel code is fully functional
and can be moved out of staging.
Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Nobuo Iwata