A reader should spend an extra moment whenever noticing a cast,
because either something special is going on that deserves extra
attention or, as is all too often the case, the code is wrong.

These casts, afaics, have all been useless.  They cast a foo* to a
foo*, cast a void* to the assigned type, cast a foo* to void*, before
assigning it to a void* variable, etc.

In a few cases I also removed an additional &...[0], which is equally
useless.

Lastly I added three FIXMEs where, to the best of my judgement, the
code appears to have a bug.  It would be good if someone could check
these.
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

- rename to target_check_cdb_and_preempt
- use non-safe list_for_each_entry
- move common check into callee (simplifying callers)
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

And make it static afterwards.
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The command
| echo rd_pages=32768 > ramdisk/control

Does not work because it writes "rd_pages=32768\n" and the parser which
matches for "rd_pages=%d" does not recognize it due to the \n. One way
of fixing this would be using "echo -n" instead.
This patch adds \n to the list of separators so we don't have to use the
-n argument which I find is more convinient.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

There is no need to make task_state_active an atomic_t given that it is
always set under the execute_task_lock so we can make it a simple bool.
Also rename it to t_state_active to be closer to the list it guards,
and make sure all checks before the list addion/removal actually happen
under execute_task_lock.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We only reach transport_complete_task once per task, so the test and set on
task_error_status is never going to have an effect.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This reorganized the headers under include/target into:

 - target_core_base.h stays as is with all target-wide data stuctures and defines
 - target_core_backend.h contains the whole interface to I/O backends
 - target_core_fabric.h contains the whole interface to fabric modules

Except for those only the various configfs macro headers stay around.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Create a new headers, drivers/target/target_core_internal.h that is supposed
to hold all target_core-internal prototypes.  Move all non-exported includes
from include/target to it, and merge the smaller prototype-only includes
inside drivers/target into it as well.  Mark functions that were found to
not be called outside their implementation file static.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Fix the following compile warning with hex2bin() usage:

drivers/target/iscsi/iscsi_target_auth.c: In function ‘chap_string_to_hex’:
drivers/target/iscsi/iscsi_target_auth.c:35: warning: ignoring return value of ‘hex2bin’, declared with attribute warn_unused_result
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

If an attribute is present (but not yet supported) it should be OK
to write 0 (a no-op) to the attribute.

This is an issue because userspace should be able to save and restore all
set attribute values without error.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

So the code assumes that the sg list is only a array while in reality
loopback SGL memory via scsi_cmnd into target-core may be already
chained.  This patch converts ramdisk code to use sg_miter logic from
scatterlist.h in order to properly support passthrough SGL usage with
transport_generic_map_mem_to_cmd() via loopback.

With this patch the bug goes away. However after umount/mount of the
device my files are gone. So something is still not right. After looking
at it for a while I decided to rewrite the that part of the code and now
things do work for me.

For reference:
- http://article.gmane.org/gmane.linux.scsi.target.devel/595
  the sg_next() conversion
- http://article.gmane.org/gmane.linux.scsi.target.devel/602
  the rewrite of the copy code

(nab: Fix compile warning in rd_MEMCPY)
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Breakout rd_MEMCPY_do_task() usage of do_div() to tmp value during
rd_request->rd_page assignment.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes fileio to use for_each_sg() when walking se_task->task_sg
memory passed into from loopback LLD struct scsi_cmnd scatterlist memory.

This addresses an issue where FILEIO backends with loopback where hitting the
following OOPs with mkfs.ext2:

|kernel BUG at include/linux/scatterlist.h:97!
|invalid opcode: 0000 [#1] PREEMPT SMP
|Modules linked in: sd_mod tcm_loop target_core_stgt scsi_tgt target_core_pscsi target_core_file target_core_iblock target_core_mod configfs scsi_mod
|
|Pid: 671, comm: LIO_fileio Not tainted 3.1.0-rc10+ #139 Bochs Bochs
|EIP: 0060:[<e0afd746>] EFLAGS: 00010202 CPU: 0
|EIP is at fd_do_task+0x396/0x420 [target_core_file]
| [<e0aa7884>] __transport_execute_tasks+0xd4/0x190 [target_core_mod]
| [<e0aa797c>] transport_execute_tasks+0x3c/0xf0 [target_core_mod]
|EIP: [<e0afd746>] fd_do_task+0x396/0x420 [target_core_file] SS:ESP 0068:dea47e90
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Some are never used, some are set but never read, dev_hoq_count is
incremented and decremented, but never read.
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The LSB of the page length is at offset 3, not 2.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

SBC-3 says:

    A TRANSFER LENGTH field set to zero specifies that 256 logical
    blocks shall be written.  Any other value specifies the number
    of logical blocks that shall be written.

The old code was always just returning the value in the TRANSFER LENGTH
byte.  Fix this to return 256 if the byte is 0.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

IO commands with a TRANSFER LENGTH of 0 are not an error; for example,
for READ (10) and WRITE (10), SBC-3 says:

    A TRANSFER LENGTH field set to zero specifies that no logical blocks
    shall be read. This condition shall not be considered an error.

In case we have nothing to do, just complete the command with good status.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The semantic patch that makes this change is available
in scripts/coccinelle/api/memdup.cocci.
Signed-off-by: NThomas Meyer <thomas@m3y3r.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch sets the missing ISCSI_FLAG_CMD_FINAL bit in
iscsit_send_task_mgt_rsp() for a struct iscsi_tm_rsp PDU.

This usage is hardcoded for all TM response PDUs in RFC-3720
section 10.6.
Reported-by: Nwhucecil <whucecil1999@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes iscsi-target handling of underflow where residual data is
causing an OOPs by using the incorrect iscsi_cmd_t->data_length initially
assigned in iscsit_allocate_se_cmd().  It resets iscsi_cmd_t->data_length
from se_cmd_t->data_length after transport_generic_allocate_tasks()
has been invoked in iscsit_handle_scsi_cmd() RX context, and converts
iscsi_cmd->residual_count usage to access iscsi_cmd->se_cmd.residual_count
to get the proper residual count set by target-core.

Reported-by: <lists@internyc.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes transport_generic_map_mem_to_cmd() to reject SCSI data
overflow and to send exception status with CHECK_CONDITION + TCM_INVALID_CDB_FIELD
for fabrics that are passing a pre-populated struct scatterlist (eg: tcm_loop
and iscsi-target) being mapped into se_cmd->t_data_sg and se_cmd->t_data_nents.

This addresses an OOPs where transport_allocate_data_tasks() would walk
the incorrect post OVERFLOW cmd->data_length value beyond the end of
the passed scatterlist.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

And use a SCF_BIDI flag instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

And use a SCF_FUA flag instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We never walk ordered_cmd_list in the se_device, so remove all code related
to supporting it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We already have a perfectly valid se_device pointer in the command, so
remove the mostly useless duplicates.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch removes config_item_name() informational usage of
TFO->free_wwn() treewide in loopback, tcm_fc, ib_srpt and
tcm_vhost module code.

Using v4 target_core_fabric_configfs.c logic, a fabric call for
config_item_name() in TFO->drop_wwn() context returns NULL as
target_fabric_drop_wwn() invoking config_item_put() ->
config_group_put() will release fabric_port->port_wwn.wwn_group
before the last config_item_put() -> TFO->drop_wwn() is
invoked.
Reported-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

While testing ib_srpt I noticed that the target system became
rather unresponsive during intensive I/O. The patch below made
my target system responsive again during I/O without decreasing
performance.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds missing kfree() for an allocation in iscsi_login_zero_tsih_s1()
code, and make transport_init_session() check for IS_ERR() returns.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch removes legacy usage of PYX_TRANSPORT_* return codes in a number
of locations and addresses cases where transport_generic_request_failure()
was returning the incorrect sense upon CHECK_CONDITION status after the
v3.1 converson to use errno return codes.

This includes the conversion of transport_generic_request_failure() to
process cmd->scsi_sense_reason and handle extra TCM_RESERVATION_CONFLICT
before calling transport_send_check_condition_and_sense() to queue up
response status.  It also drops PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES legacy
usgae, and returns TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE w/ a response
for these cases.

transport_generic_allocate_tasks(), transport_generic_new_cmd(), backend
SCF_SCSI_DATA_SG_IO_CDB ->do_task(), and emulated ->execute_task() have
all been updated to set se_cmd->scsi_sense_reason and return errno codes
universally upon failure.  This includes cmd->scsi_sense_reason assignment
in target_core_alua.c, target_core_pr.c and target_core_cdb.c emulation code.

Finally it updates fabric modules to remove the legacy usage, and for
TFO->new_cmd_map() callers forwards return values outside of fabric code.
iscsi-target has also been updated to remove a handful of special cases
related to the cleanup and signaling QUEUE_FULL handling w/ ft_write_pending()

(v2: Drop extra SCF_SCSI_CDB_EXCEPTION check during failure from
     transport_generic_new_cmd, and re-add missing task->task_error_status
     assignment in transport_complete_task)

Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Instead of calling into transport_emulate_control_cdb from
__transport_execute_tasks for some CDBs always set up ->exectute_tasks
in the command sequence and use it uniformly.

(nab: Add default passthrough break for SERVICE_ACTION_IN)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

All ->execute_task instances now need to complete the I/O explicitly,
which can either happen synchronously or asynchronously.

Note that a lot of the CDB emulations appear to return success even if
some lowlevel operations failed.  Given that this is an existing issue
this patch doesn't change that fact.

(nab: Adding missing switch breaks in PR-IN + PR_OUT)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Encapsulate each CDB emulation into a function of its own, to prepare
setting ->exectute_task to these routines.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We want to be able to handle all CDBs through it and remove hacks like
always using the first task in a CDB in target_report_luns.

Also rename the callback to ->execute_task to better describe its use.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Split core_scsi2_emulate_crh into one routine each for the
PERSISTENT_RESERVE_IN and PERSISTENT_RESERVE_OUT side.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Split core_scsi2_emulate_crh into one routine each for the reserve and
release side.  The common code now is in a helper called by both
routines.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds the initial pieces of generic active I/O shutdown logic.
This is intended to be a 'opt-in' feature for fabric modules that
includes the following functions to provide a mechinism for fabric
modules to track se_cmd via se_session->sess_cmd_list:

*) target_get_sess_cmd() - Add se_cmd to sess->sess_cmd_list, called
   from fabric module incoming I/O path.
*) target_put_sess_cmd() - Check for completion or drop se_cmd from
   ->sess_cmd_list
*) target_splice_sess_cmd_list() - Splice active I/O list from
   ->sess_cmd_list to ->sess_wait_list, can called with HW fabric
   lock held.
*) target_wait_for_sess_cmds() - Walk ->sess_wait_list waiting on
   individual ->cmd_wait_comp.  Optional transport_wait_for_tasks()
   call.

target_splice_sess_cmd_list() is allowed to be called under HW fabric
lock, and performs the splice into se_sess->sess_wait_list and set
se_cmd->cmd_wait_set.  Then target_wait_for_sess_cmds() walks the list
waiting for individual target_put_sess_cmd() fabric callbacks to
complete.

It also adds TFO->check_release_cmd() to split the completion and memory
release calls, where a fabric module uses target_put_sess_cmd() to check
for I/O completion during session shutdown.  This is currently pushed out
into fabric modules as current fabric code may sleep here waiting for
TFO->check_stop_free() to complete in main response path, and because
target_wait_for_sess_cmds() calling TFO->release_cmd() to free fabric
descriptor memory directly.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas A. Bellinger <nab@linux-iscsi.org>

The commit

    target: use a workqueue for I/O completions

accidentally removed setting t_tasks_failed in transport_complete_task.
Add it back in a slightly cleaner way; now it is set for every failed task
instead of special casing the last one completing by using the success
argument directly for it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas A. Bellinger <nab@linux-iscsi.org>