litmus-rt.git/Documentation/target, branch test

target/user: Only support full command pass-through

2015-05-31T02:57:48+00:00

After much discussion, give up on only passing a subset of SCSI commands
to userspace and pass them all. Based on what pscsi is doing, make sure
to set SCF_SCSI_DATA_CDB for I/O ops, and define attributes identical to
pscsi.

Make hw_block_size configurable via dev param.

Remove mention of command filtering from tcmu-design.txt.

Signed-off-by: Andy Grover 
Reviewed-by: Ilias Tsitsimpis 
Signed-off-by: Nicholas Bellinger

target/user: Update example code for new ABI requirements

2015-05-31T02:57:33+00:00

We now require that the userspace handler set a bit if the command is not
handled.

Update calls to tcmu_hdr_get_op for v2.

Signed-off-by: Andy Grover 
Reviewed-by: Ilias Tsitsimpis 
Signed-off-by: Nicholas Bellinger

target/user: Disallow full passthrough (pass_level=0)

2015-05-03T01:20:51+00:00

TCMU requires more work to correctly handle both user handlers that want
all SCSI commands (pass_level=0) for a se_device, and also handlers that
just want I/O commands and let the others be emulated by the kernel
(pass_level=1). Only support the latter for now.

For full passthrough, we will need to support a second se_subsystem_api
template, due to configfs attributes being different between the two modes.
Thus pass_level is extraneous, and we can remove it.

The ABI break for TCMU v2 is already applied for this release, so it's
best to do this now to avoid another ABI break in the future.

Signed-off-by: Andy Grover 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Nicholas Bellinger

target: Version 2 of TCMU ABI

2015-04-20T05:40:26+00:00

The initial version of TCMU (in 3.18) does not properly handle
bidirectional SCSI commands -- those with both an in and out buffer. In
looking to fix this it also became clear that TCMU's support for adding
new types of entries (opcodes) to the command ring was broken. We need
to fix this now, so that future issues can be handled properly by adding
new opcodes.

We make the most of this ABI break by enabling bidi cmd handling within
TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req.
This enables TCMU to describe bidi commands, but further kernel work is
needed for full bidi support.

Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn
__pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags,
"kflags" and "uflags" respectively.

Update version fields so userspace can tell the interface is changed.

Update tcmu-design.txt with details of how new stuff works:
- Specify an additional requirement for userspace to set UNKNOWN_OP
  (bit 0) in hdr.uflags for unknown/unhandled opcodes.
- Define how Data-In and Data-Out fields are described in req.iov[]

Changed in v2:
- Change name of SKIPPED bit to UNKNOWN bit
- PAD op does not set the bit any more
- Change len_op helper functions to take just len_op, not the whole struct
- Change version to 2 in missed spots, and use defines
- Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd
  parameters need to be included
- Add iov_dif_cnt field to specify buffers used for DIF info in iov[]
- Rearrange fields to naturally align cdb_off
- Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd
- Wrap some overly long UPDATE_HEAD lines

(Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias)

Signed-off-by: Andy Grover 
Reviewed-by: Ilias Tsitsimpis 
Signed-off-by: Nicholas Bellinger

target: fix tcm_mod_builder.py

2015-04-16T05:47:28+00:00

Fix a misplaced comma I introduced.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Nicholas Bellinger

target: simplify the target template registration API

2015-04-14T19:28:41+00:00

Instead of calling target_fabric_configfs_init() +
target_fabric_configfs_register() / target_fabric_configfs_deregister()
target_fabric_configfs_free() from every target driver, rewrite the API
so that we have simple register/unregister functions that operate on
a const operations vector.

This patch also fixes a memory leak in several target drivers. Several
target drivers namely called target_fabric_configfs_deregister()
without calling target_fabric_configfs_free().

A large part of this patch is based on earlier changes from
Bart Van Assche .

(v2: Add a new TF_CIT_SETUP_DRV macro so that the core configfs code
can declare attributes as either core only or for drivers)

Signed-off-by: Christoph Hellwig 
Signed-off-by: Nicholas Bellinger

Documentation/target: Update fabric_ops to latest code

2015-01-06T21:46:49+00:00

This patch updates tcm_mod_builder.py to add/drop a handful of
struct target_core_fabric_ops functions to sync up with the
latest requirements to function in target_fabric_tf_ops_check().

Signed-off-by: Nicholas Bellinger

target: Add documentation on the target userspace pass-through driver

2014-10-03T04:35:54+00:00

Describes the driver and its interface to make it possible for user
programs to back a LIO-exported LUN.

Thanks to Richard W. M. Jones for review, and supplementing this doc
with the first two paragraphs.

Signed-off-by: Andy Grover 
Signed-off-by: Nicholas Bellinger

target: Remove TF_CIT_TMPL macro

2013-10-16T20:35:02+00:00

Remove a lingering macro that just hid a dereference.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Andy Grover 
Signed-off-by: Nicholas Bellinger

Documentation: replace strict_strtoul() with kstrtoul()

2013-08-20T10:56:26+00:00

The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.

Signed-off-by: Jingoo Han 
Signed-off-by: Jiri Kosina