tree b2a7851511b2ddb943b9ff7ce7c8a96c3ac2a8bb
parent 6c2fce2ef6b4821c21b5c42c7207cb9cf8c87eda
author Neil Brown <neilb@notabene.brown> 1214605893 +1000
committer Neil Brown <neilb@notabene.brown> 1214605893 +1000

rationalise return value for ->hot_add_disk method.

For all array types but linear, ->hot_add_disk returns 1 on
success, 0 on failure.
For linear, it returns 0 on success and -errno on failure.

This doesn't cause a functional problem because the ->hot_add_disk
function of linear is used quite differently to the others.
However it is confusing.

So convert all to return 0 for success or -errno on failure
and fix call sites to match.

Signed-off-by: Neil Brown <neilb@suse.de>