adapter: Do not poll when there is an active tag

When there is an active tag and a request to start polling is
received by neard, it will discard the currently registered tag
and requests that the kernel start another poll.  The kernel receives
this request and returns EBUSY because there is already an active tag.
neard receives this failure and reports it to the poll requestor.
At this point, the tag is active but neard no longer has any knowledge
of it.  Fix this by returning EBUSY when there is an active tag and
a new poll request is received.

Signed-off-by: Mark Greer <mgreer@animalcreek.com>
1 file changed