linux-toradex.git/Documentation/target, branch v4.1-rc4

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

target: Simplify fabric sense data length handling

2012-09-18T00:12:58+00:00

Every fabric driver has to supply a se_tfo->set_fabric_sense_len()
method, just so iSCSI can return an offset of 2.  However, every fabric
driver is already allocating a sense buffer and passing it into the
target core, either via transport_init_se_cmd() or target_submit_cmd().

So instead of having iSCSI pass the start of its sense buffer into the
core and then later tell the core to skip the first 2 bytes, it seems
easier for iSCSI just to do the offset of 2 when it passes the sense
buffer into the core.  Then we can drop the se_tfo->set_fabric_sense_len()
everywhere, and just add a couple of lines of code to iSCSI to set the
sense data length to the beginning of the buffer right before it sends
it over the network.

(nab: Remove .set_fabric_sense_len usage from tcm_qla2xxx_npiv_ops +
      change transport_get_sense_buffer to follow v3.6-rc6 code w/o
      ->set_fabric_sense_len usage)

Signed-off-by: Roland Dreier 
Signed-off-by: Nicholas Bellinger

target: Remove unused target_core_fabric_ops.get_fabric_sense_len method

2012-09-17T23:15:47+00:00

There are no callers of se_tfo->get_fabric_sense_len(), so we should
stop having every fabric driver implement it.

Signed-off-by: Roland Dreier 
Signed-off-by: Nicholas Bellinger

Documentation: Fix typo in tcm_mod_builder.py

2012-02-10T08:52:18+00:00

Correct spelling "alocate" to "allocate" in
Documentation/target/tcm_mod_builder.py

Signed-off-by: Masanari Iida 
Signed-off-by: Jiri Kosina