From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Greetings all,
This series adds generic TPE=1 / UNMAP support into TCM Core and TCM/IBLOCK +
TCM/FILEIO subsystem plugin code code to issue blkdev_issue_discard() for
struct block_device that support QUEUE_FLAG_DISCARD. Using TPE=1 / UNMAP
is also supported with direct struct request passthrough using TCM/pSCSI
and everything required for this to function is included in patch #1.
Patch #1 also includes the addition of the SBC-3 Block Limits VPD (0xb0) page
and adds the following UNMAP related knobs returned into configfs attributes in
/sys/kernel/config/target/core/$HBA/$DEV/attrib, the new ones include:
*) optimal_sectors (currently set to our ->max_sectors)
*) max_unmap_block_desc_count (set to 0 by default)
*) max_unmap_lba_count (set to 0 by default)
*) unmap_granularity (set to 0 by default)
*) unmap_granularity_alignment (set to 0 by default)
Patch #2 includes the necessary changes to IBLOCK to detect QUEUE_FLAG_DISCARD
and call transport_generic_unmap() for each UNMAP op.
Patch #3 includes the necessary changes to FILEIO w/ a valid S_ISBLK() to
detect QUEUE_FLAG_DISCARD and call transport_generic_unmap() for each UNMAP
op. This is the one item I am unsure about, eg: using iget() + iput() to locate
struct block_device for blk_issue_discard()..? hch..?
So far these patches have been tested with scsi_debug LUNs w/ TPE=1 with both
IBLOCK and FILEIO TPE=1 emulation modes, along with TCM/pSCSI passthrough mode on
v2.6.36-rc4 HVM. Here is what Block Limits VPD output looks like via TCM_Loop:
target# sg_inq --page=0xb0 /dev/sdh
VPD INQUIRY: Block limits page (SBC)
Maximum compare and write length: 0 blocks
Optimal transfer length granularity: 1 blocks
Maximum transfer length: 1024 blocks
Optimal transfer length: 1024 blocks
Maximum prefetch, xdread, xdwrite transfer length: 0 blocks
Maximum unmap LBA count: 0
Maximum unmap block descriptor count: 0
Optimal unmap granularity: 0
Unmap granularity alignment valid: 0
Unmap granularity alignment: 0
and with sg_unmap:
target# sg_unmap -v --lba=78 --num=4 --verbose /dev/sdh
open /dev/sdh with flags=0x802
unmap cdb: 42 00 00 00 00 00 00 00 18 00
unmap parameter list:
00 16 00 10 00 00 00 00 00 00 00 00 00 00 00 4e
00 00 00 04 00 00 00 00
Comments are welcome!
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
Nicholas Bellinger (3):
tcm: Add Thin Provisioning / UNMAP emulation and Block Limits VPD
page
tcm/iblock: Add UNMAP / Block DISCARD support
tcm/fileio: Add UNMAP / Block DISCARD support
drivers/target/target_core_configfs.c | 24 +++++
drivers/target/target_core_device.c | 90 +++++++++++++++++++
drivers/target/target_core_file.c | 53 +++++++++++-
drivers/target/target_core_iblock.c | 19 ++++-
drivers/target/target_core_transport.c | 152 ++++++++++++++++++++++++++++++++
include/target/target_core_base.h | 9 ++-
include/target/target_core_device.h | 6 ++
include/target/target_core_transport.h | 11 +++
8 files changed, 361 insertions(+), 3 deletions(-)
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