This reverts commit db54facd56a40e7766bf7f7cda1ae138e72a691c which was
commit a4e84aae8139aca9fbfbced1f45c51ca81b57488 upstream.

Ben writes:
    MQ IO schedulers were introduced in 4.11, so this shouldn't be
    needed in older branches.  It also causes a performance
    regression (fixed upstream).  Please revert this for 4.4 and
    4.9.

So let's revert it!

Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit a4e84aae8139aca9fbfbced1f45c51ca81b57488 ]

mtip32xx supposes that 'request_idx' passed to .init_request()
is tag of the request, and use that as request's tag to initialize
command header.

After MQ IO scheduler is in, request tag assigned isn't same with
the request index anymore, so cause strange hardware failure on
mtip32xx, even whole system panic is triggered.

This patch fixes the issue by initializing command header via
request's real tag.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

All drivers use the default, so provide an inline version of it.  If we
ever need other queue mapping we can add an optional method back,
although supporting will also require major changes to the queue setup
code.

This provides better code generation, and better debugability as well.

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

We get 1 warning when biuld kernel with W=1:
drivers/block/mtip32xx/mtip32xx.c:3689:6: warning: no previous prototype for
 'mtip_block_release' [-Wmissing-prototypes]

In fact, this function is only used in the file in which it is declared
and don't need a declaration, but can be made static.
so this patch marks it 'static'.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: Jens Axboe <axboe@fb.com>

For block drivers that specify a parent device, convert them to use
device_add_disk().

This conversion was done with the following semantic patch:

    @@
    struct gendisk *disk;
    expression E;
    @@

    - disk->driverfs_dev = E;
    ...
    - add_disk(disk);
    + device_add_disk(E, disk);

    @@
    struct gendisk *disk;
    expression E1, E2;
    @@

    - disk->driverfs_dev = E1;
    ...
    E2 = disk;
    ...
    - add_disk(E2);
    + device_add_disk(E1, E2);

...plus some manual fixups for a few missed conversions.

Cc: Jens Axboe <axboe@fb.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The req operation REQ_OP is separated from the rq_flag_bits
definition. This converts the block layer drivers to
use req_op to get the op from the request struct.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

The driver calls it with 0 for flags, since it doesn't have a writeback
cache. Just remove the call, as it's a no-op right now.

Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Only a single tags array anyway.

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

exec_drive_taskfile() checks for dma mapping errors by comparison
returned address with zero, while pci_dma_mapping_error() should be used.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Jens Axboe <axboe@fb.com>

We always return BLK_EH_RESET_TIMER, so no point in storing that in
an integer.

Signed-off-by: Jens Axboe <axboe@fb.com>