tree d0f632fa9b205d5fbcc76ff1cf8cba63112c7da8
parent ce2c350b2cfe5b5ca5023a6b1ec4d21821d39add
author Christoph Hellwig <hch@lst.de> 1392049740 -0700
committer Jens Axboe <axboe@fb.com> 1392049740 -0700

blk-mq: rework flush sequencing logic

Witch to using a preallocated flush_rq for blk-mq similar to what's done
with the old request path.  This allows us to set up the request properly
with a tag from the actually allowed range and ->rq_disk as needed by
some drivers.  To make life easier we also switch to dynamic allocation
of ->flush_rq for the old path.

This effectively reverts most of

    "blk-mq: fix for flush deadlock"

and

    "blk-mq: Don't reserve a tag for flush request"

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