[PATCH V4 0/3] xen-blkfront/blkback discard support

[Li Dongyang <lidongyang@novell.com>]

Dear list, 
This is the V4 of the trim support for xen-blkfront/blkback,
Now we move BLKIF_OP_TRIM to BLKIF_OP_DISCARD, and dropped all
"trim" stuffs in the patches, and use "discard" instead.
Also we updated the helpers of blkif_x86_{32|64}_request or we
will meet problems using a non-native protocol.
And this patch has been tested with both SSD and raw file,
with SSD we will forward the discard command and with raw file,
the disk usage will reduce as we send discard request in the guest.

Changelog V4:
    switch from BLKIF_OP_TRIM to BLKIF_OP_DISCARD
    make blkback work with non-native protocol
    do not abort connection in blkback if we can not setup discard in xenstore
Changelog V3: 
    rebased on linus's tree 
    enum backend types in blkif instead of flags in the interface header 
    more reasonable names in xenstore 
    move trim requesting handling to a separate function 
    do not re-enable interrupts unconditionally when handling response 
    set info->feature-trim only when we have all info needed for request queue 
Changelog V2: 
    rebased on Jeremy's tree 
    fixes according to Jan Beulich's comments 

Li Dongyang (3):
  xen-blkfront: add BLKIF_OP_DISCARD and discard request struct
  xen-blkfront: teach blkfront driver to handle discard requests
  xen-blkback: discard requests handling in blkback driver

 drivers/block/xen-blkback/blkback.c |   87 +++++++++++++++++++++++-----
 drivers/block/xen-blkback/common.h  |   93 ++++++++++++++++++++++++-----
 drivers/block/xen-blkback/xenbus.c  |   58 ++++++++++++++++++
 drivers/block/xen-blkfront.c        |  111 +++++++++++++++++++++++++++-------
 include/xen/interface/io/blkif.h    |   36 +++++++++++
 5 files changed, 331 insertions(+), 54 deletions(-)

-- 
1.7.6