[RFC PATCHv2 0/3] nvme: queue_if_no_path functionality

[Hannes Reinecke <hare@suse.de>]

Hi all,

this is a patchset based on Keiths original patch for restoring pre-fabrics
behaviour when the last path to a multipath device is removed.
Originally, the nvme device had been removed once the underlying hardware
had been removed. With the introduction of multipath support things changed;
it's now the 'CMIC' bit in the controller identification which controls the
behaviour. If it's set to non-zero, the device is retained even if the hardware
is removed. While this is okay for fabrics (as we can manually connect and
disconnect the devices), for nvme-pci this means that PCI hotplug ceases
to work as the device is never removed, and when reinserting the hardware
a new nvme device is created.
This patchset introduces a 'queue_if_no_path' flag to control the handling of
the last path; it's set for fabrics to retain the current functionality,
but unset for PCI to revert to the original, pre-fabrics behaviour.

Hannes Reinecke (2):
  nvme: add 'queue_if_no_path' semantics
  nvme: add 'queue_if_no_path' sysfs attribute

Keith Busch (1):
  nvme-mpath: delete disk after last connection

 drivers/nvme/host/core.c      | 42 +++++++++++++++++++++++++++++++++++++++++-
 drivers/nvme/host/multipath.c |  5 ++++-
 drivers/nvme/host/nvme.h      |  3 ++-
 3 files changed, 47 insertions(+), 3 deletions(-)

-- 
2.16.4


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