[Trusty][SRU]Pull Request: Storage driver performance updates for Trusty requested in lp1445195

[Joseph Salisbury]

This pull request is for storage driver performance updates requested in bug lp1445195 and is 
specific to Trusty.  The bug reporter is requesting these patches in all Ubuntu releases.  
Vivid, Utopic and now Trusty have acceptable testing results so far.  

However, Trusty required more changes compared to Utopic and Vivid.  It also required prereq changes 
that are non-specific to Hyper-V:
"89d9a56 [SCSI] add support for per-host cmd pools"
"b54197c virtio_scsi: use cmd_size"

If these are too many changes for a stable release, we may just require the use of a 
LTS Backport kernel for Trusty. 



The following changes since commit e2a0bfcddd9d1c398b5d16e1b8ebf44532009807:

  UBUNTU: Ubuntu-3.13.0-57.95 (2015-06-18 18:44:04 +0100)

are available in the git repository at:

  kernel.ubuntu.com:/srv/kernel.ubuntu.com/git/jsalisbury/bugs/lp1445195/ubuntu-trusty.git 

for you to fetch changes up to d3dafd6ed4a47edd855d50f756955e90b6e8f82e:

  storvsc: Set the SRB flags correctly when no data transfer is needed (2015-07-02 12:17:35 -0400)

----------------------------------------------------------------
Christoph Hellwig (3):
      [SCSI] add support for per-host cmd pools
      virtio_scsi: use cmd_size
      storvsc: use cmd_size to allocate per-command data

K. Y. Srinivasan (10):
      Drivers: hv: vmbus: Cleanup the packet send path
      storvsc: fix a bug in storvsc limits
      Drivers: hv: vmbus: Support a vmbus API for efficiently sending page arrays
      scsi: storvsc: Increase the ring buffer size
      scsi: storvsc: Size the queue depth based on the ringbuffer size
      scsi: storvsc: Always send on the selected outgoing channel
      scsi: storvsc: Retrieve information about the capability of the target
      scsi: storvsc: Don't assume that the scatterlist is not chained
      scsi: storvsc: Set the tablesize based on the information given by the host
      storvsc: Set the SRB flags correctly when no data transfer is needed

 drivers/hv/channel.c       |  86 ++++++++---
 drivers/hv/hyperv_vmbus.h  |   4 +-
 drivers/hv/ring_buffer.c   |  17 +--
 drivers/scsi/scsi.c        |  96 +++++++++---
 drivers/scsi/storvsc_drv.c | 356 +++++++++++++++++++++------------------------
 drivers/scsi/virtio_scsi.c |  25 +---
 include/linux/hyperv.h     |  33 ++++-
 include/scsi/scsi_cmnd.h   |   9 ++
 include/scsi/scsi_host.h   |   7 +
 9 files changed, 370 insertions(+), 263 deletions(-)