CAUTION:
Previously CCD would be different from all other disks in
the system in that there were no "ccd0" device, only a
"ccd0c" device.
This is no longer so after this commit. If you access a
ccd device through the "/dev/ccd0c" device _and_ have not
actually put a BSD disklabel on the device, you will have
to use the name "/dev/ccd0". If your CCD device contains
a BSD disklabel there should be no difference.
You need to recompile ccdconfig(8) using the changed
src/sys/sys/ccdvar.h for the -g "show me" option to work.
I have run the regression test I created before I started
overhauling CCD and it flags no problems, but this code
is mildly evil, so take care. If you would cry if you lost
what's on CCD, make a back before you upgrade.
Create separate cdevsw for the /dev/ccd.ctl device.
Remove the cloning function, the disk-minilayer will do all naming
for us.
Remove the ccdunit and ccdpart functions and carry the softc pointer
in the relevant dev_t's and structures.
Release all memory when a CCD device is unconfigured, previously
the softc would linger behind.
Remove all traces of BSD disklabel fiddling code.
Remove ccdpsize, the disk mini-layer does this for us.
Don't allocate memory with M_WAITOK in ccdstrategy().
Remove boundary checks which the disk mini-layer does for us.
Don't allocate space for more than 2 ccdbuf, RAID was never implemented.
NB: I have not tried to address any of the preexisting ailments of CCD.
0f76d6d822