tree 1662ce0587fc786881a0c8ee488a7ce08f76d3eb
parent 6730b51f1d128910f628c43bb0d2fb655c7ceefe
author Jean-Philippe Brucker <jean-philippe.brucker@arm.com> 1547129568 +0000
committer Will Deacon <will.deacon@arm.com> 1548140126 +0000

threadpool: Add cancel() function

When resetting a virtqueue, it is often necessary to make sure that the
associated threadpool job isn't running anymore. Add a function to
cancel a job.

A threadpool job has three states: idle, queued and running. A job is
queued when it is in the job list. It is running when it is out the
list, but its signal count is greater than zero. It is idle when it is
both out of the list and its signal count is zero. The cancel() function
simply waits for the job to be idle. It is up to the caller to make sure
that the job isn't queued concurrently.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>