tree c8ff5e127118a4b6de68734be5a8e0560110debe
parent 075790ebba4a1eb297f9875e581b55c0382b1f3d
author Keith Busch <keith.busch@intel.com> 1456330554 -0700
committer Jens Axboe <axboe@fb.com> 1457041369 -0700

NVMe: Fix namespace removal deadlock

This patch makes nvme namespace removal lockless. It is up to the caller
to ensure no active namespace scanning is occuring. To ensure no scan
work occurs, the nvme pci driver adds a removing state to the controller
device to avoid queueing scan work during removal. The work is flushed
after setting the state, so no new scan work can be queued.

The lockless removal allows the driver to cleanup a namespace
request_queue if the controller fails during removal. Previously this
could deadlock trying to acquire the namespace mutex in order to handle
such events.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>