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[RESEND RFC PATCH 00/32] separate operations from flags in the bio/request structs

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This is just a resend of the patchset from earlier today. There was
a error in the middle of sending the set, so it looks like 10 - 32 got
dropped.

There are a couple new block layer commands we are trying to add support
for in the near term:

compare and write
http://www.spinics.net/lists/target-devel/msg07826.html

copy offload/extended copy/xcopy
https://www.redhat.com/archives/dm-devel/2014-July/msg00070.html

The problem is if we contine to add more commands we will have to one day
extend the cmd_flags/bi_rw fields again. To prevent that, this patchset
separates the operation (REQ_WRITE, REQ_DISCARD, REQ_WRITE_SAME, etc) from
the flags (REQ_SYNC, REQ_QUIET, etc) in the bio and request structs. In the
end of this set, we will have two fields bio->bi_op/request->op and
bio->bi_rw/request->cmd_flags.

The patches were made against Jens's linux-block tree's for-linus branch:
https://git.kernel.org/cgit/linux/kernel/git/axboe/linux-block.git/log/?h=for-linus
(last commit a22c4d7e34402ccdf3414f64c50365436eba7b93).

I have done some basic testing for a lot of the drivers and filesystems,
but I wanted to get comments before trying to track down more hardware/
systems for testing.


Known issues:
- REQ_FLUSH is still a flag, but should probably be a operation.
 For lower level drivers like SCSI where we only get a flush, it makes
more sense to be a operation. However, upper layers like filesystems
can send down flushes with writes, so it is more of a flag for them.
I am still working on this.

- There is a regression with the dm flakey target. It currently
cannot corrupt the operation values.

- The patchset is a little awkward. It touches so much code,
but I wanted to maintain git bisectibility, so there is lots of compat code
left around until the last patches where everyting is cleaned up.



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[RESEND RFC PATCH 00/32] separate operations from flags in the bio/request structs mchristi@redhat.com - 2015-11-04 23:10 +0100
  [PATCH 32/32] block: remove __REQ op defs and reduce bi_op/bi_rw sizes mchristi@redhat.com - 2015-11-04 23:10 +0100
    Re: [PATCH 32/32] block: remove __REQ op defs and reduce bi_op/bi_rw  sizes Christoph Hellwig <hch@infradead.org> - 2015-11-07 11:30 +0100
  [PATCH 11/32] gfs2: prepare for bi_rw split mchristi@redhat.com - 2015-11-04 23:10 +0100
  [PATCH 23/32] block/fs: pass in op and flags to ll_rw_block mchristi@redhat.com - 2015-11-04 23:10 +0100
  [PATCH 13/32] mm: prepare for bi_rw split mchristi@redhat.com - 2015-11-04 23:10 +0100
  [PATCH 24/32] dm: pass dm stats data dir instead of bi_rw mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 21/32] bcache: set bi_op to REQ_OP mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 27/32] cfq/cgroup: pass operation and flags seperately mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 12/32] xfs: prepare for bi_rw split mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 22/32] block/fs/drivers: set bi_op to REQ_OP mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 20/32] md: set bi_op to REQ_OP mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 30/32] drbd: don't use bi_rw for operations mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 28/32] block/fs/drivers: use bio/rq_data_dir helpers mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 18/32] drbd: set bio bi_op to REQ_OP mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 26/32] ide cd: do not set REQ_WRITE on requests. mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 25/32] block: add operation field to request struct mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 19/32] block: add helper to get data dir from op mchristi@redhat.com - 2015-11-04 23:20 +0100
    Re: [dm-devel] [PATCH 19/32] block: add helper to get data dir from  op Mike Christie <mchristi@redhat.com> - 2015-11-05 18:40 +0100
      Re: [dm-devel] [PATCH 19/32] block: add helper to get data dir from  op Christoph Hellwig <hch@infradead.org> - 2015-11-07 11:20 +0100
  [PATCH 29/32] block/drivers: rm request cmd_flags REQ_OP use mchristi@redhat.com - 2015-11-04 23:20 +0100
  [PATCH 05/32] drbd: prepare drbd for bi_rw split mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 03/32] dio/btrfs: prep dio->submit_bio users for bi_rw split. mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 16/32] block/fs/md: pass in op and flags to submit_bh mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 07/32] dm: prepare for bi_rw split mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 10/32] f2fs: prepare for bi_rw split mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 15/32] btrfs: prepare for bi_rw split mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 08/32] target: prepare for bi_rw split mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 17/32] block: add operation field to bio struct mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 06/32] xen blkback: prepare for bi_rw split mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 02/32] block/fs/mm: prepare submit_bio_wait users for bi_rw split mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 14/32] block/fs/mm: pass in op and flags to submit_bio mchristi@redhat.com - 2015-11-04 23:30 +0100
  [PATCH 01/32] block/fs: add REQ_OP definitions. mchristi@redhat.com - 2015-11-04 23:40 +0100
  Re: [RESEND RFC PATCH 00/32] separate operations from flags in the  bio/request structs Bob Peterson <rpeterso@redhat.com> - 2015-11-05 17:50 +0100
  Re: [RESEND RFC PATCH 00/32] separate operations from flags in the  bio/request structs Christoph Hellwig <hch@infradead.org> - 2015-11-07 11:20 +0100

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