tcm: Add pre-allocated struct se_cmd descriptor support

From: Nicholas Bellinger <[email protected]>

Greetings Joe and Co,

This patch series adds support to TCM Core for allowing TCM fabric modules to use pre-allocated struct se_cmd descriptors and sense data buffers living within fabric module dependent data structures. This patch series was orginally inspiried as a future TCM v4.1 optimization by Joe Eykholt in a thread here:

http://groups.google.com/group/linux-iscsi-target-dev/browse_thread/thread/88a6434fa9cad163

The first patch adds the necessary TCM Core infrastructure to support the initialization and proper release of struct se_cmd living within TCM fabric module dependent data structures. This includes the conversion of existing logic and the addition of the new transport_init_se_cmd() EXPORT_SYMBOL() code.

The second patch converts the TCM_Loop fabric module to use struct tcm_loop_cmd->tl_se_cmd and struct tcm_loop_cmd->tl_sense_buf.

The third patch converts the LIO-Target fabric module to use struct iscsi_cmd->se_cmd and struct iscsi_cmd->sense_buffer.

The forth patch converts the Open-FCoE.org / TCM_FC fabric module to use struct ft_cmd->se_cmd and struct ft_cmd->ft_sense_buffer.

So far this has been lightly tested with TCM_Loop and LIO-Target fabric modules on v2.6.36-rc3 HVM x86 guest, and will require more testing to properly ensure the patch series is functionally correct, and that other new TCM modules are still 100% functional using the existing *transport_alloc_se_cmd() callers.

Many thanks again to Joe for noticing the oppourtunity for improvement within the per I/O descriptor path and making this astute suggestion!!

Nicholas Bellinger (4):
tcm: Add support for fabric module provided struct se_cmd descriptors
tcm_loop: Convert to pre-allocated struct se_cmd descriptors
lio-target: Convert to use pre-allocated struct se_cmd descriptors
tcm_fc: Convert to use pre-allocated struct se_cmd descriptors

 drivers/target/lio-target/iscsi_target.c       |   27 +++--
 drivers/target/lio-target/iscsi_target_core.h  |   10 ++-
 drivers/target/lio-target/iscsi_target_erl1.c  |    8 +-
 drivers/target/lio-target/iscsi_target_tmr.c   |   23 ++---
 drivers/target/lio-target/iscsi_target_util.c  |   44 ++++----
 drivers/target/target_core_transport.c         |  131 +++++++++++++++++++-----
 drivers/target/tcm_fc/tcm_fc.h                 |    3 +-
 drivers/target/tcm_fc/tfc_cmd.c                |   59 +++++------
 drivers/target/tcm_fc/tfc_io.c                 |    4 +-
 drivers/target/tcm_loop/tcm_loop_core.h        |    6 +-
 drivers/target/tcm_loop/tcm_loop_fabric.c      |   12 +-
 drivers/target/tcm_loop/tcm_loop_fabric_scsi.c |   37 +++----
 include/target/target_core_base.h              |    3 +
 include/target/target_core_transport.h         |    4 +
 14 files changed, 226 insertions(+), 145 deletions(-)