NVMe: Update copyright headers

Make the copyright dates accurate and remove the final paragraph that
includes the address of the FSF.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
NVMe: Improve error messages

Help people diagnose what is going wrong at initialisation time by
printing out which command has gone wrong and what the device returned.
Also fix the error message printed while waiting for reset.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
NVMe: Protect against badly formatted CQEs

If a misbehaving device posts a CQE with a command id < depth but for
one that was never allocated, the command info will have a callback
function set to NULL and we don't want to try invoking that.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
NVMe: Configure support for block flush

This configures an nvme request_queue as flush capable if the device
has a volatile write cache present.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
NVMe: conversion to blk-mq

This converts the current NVMe driver to utilize the blk-mq layer.

Contributions in this patch from:

  Sam Bradshaw <sbradshaw@micron.com>
  Jens Axboe <axboe@kernel.dk>
  Christoph Hellwig <hch@infradead.org>
  Robert Nelson <rlnelson@google.com>