CVS commit: src/sys/dev/usb

["matthew green" <mrg%netbsd.org@localhost>]

Module Name:    src
Committed By:   mrg
Date:           Mon May  6 23:46:25 UTC 2019

Modified Files:
        src/sys/dev/usb: uchcom.c

Log Message:
revert most of:

>fix uchcom(4) detach, like umodem(4) recently:
>
>- use static normally in umodem_common.c
>- add sc_refcnt, sc_lock and sc_detach_cv to softc.  usage is:
>  - sc_dying is protected by sc_lock
>  - sc_detach_cv is matched with sc_lock for cv operations
>  - sc_refcnt is increased in open and decreased in close, any time
>    it is decreased, it is checked for less than zero, and a broadcast
>    performed on sc_detach_cv.  detach waits for sc_refcnt
>  - uchcom_param() and uchcom_set() check for sc_dying
>
>this fixes pullout out an open ucom@uchcom.

it only fixes the issue by chance (slightly delays, which
allows task to run, but there is no guarantee.  real fix
is incoming for all ucom parents.


To generate a diff of this commit:
cvs rdiff -u -r1.31 -r1.32 src/sys/dev/usb/uchcom.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.