Commit Graph

130 Commits

Author SHA1 Message Date
Roland Dreier 895f302252 target: Set additional sense length field in sense data
The target code was not setting the additional sense length field in the
sense data it returned, which meant that at least the Linux stack
ignored the ASC/ASCQ fields.  For example, without this patch, on a
tcm_loop device:

    # sg_raw -v /dev/sda 2 0 0 0 0 0

gives

        cdb to send: 02 00 00 00 00 00
    SCSI Status: Check Condition

    Sense Information:
     Fixed format, current;  Sense key: Illegal Request
      Raw sense data (in hex):
            70 00 05 00 00 00 00 00

while after the patch we correctly get the following (which matches what
a regular disk returns):

        cdb to send: 02 00 00 00 00 00
    SCSI Status: Check Condition

    Sense Information:
     Fixed format, current;  Sense key: Illegal Request
     Additional sense: Invalid command operation code
     Raw sense data (in hex):
            70 00 05 00 00 00 00 0a  00 00 00 00 20 00 00 00
            00 00

Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: stable@kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-16 06:29:04 +00:00
Nicholas Bellinger 6d5b597560 target: Remove legacy device status check from transport_execute_tasks
This patch removes a legacy se_dev_check_online() check from within
transport_execute_tasks() that should no longer be necessary as
transport_lookup_cmd_lun() is already making this call.

Using transport_cmd_check_stop() from transport_execute_tasks() should
already be checking per se_cmd context for each descriptor upon active
I/O shutdown, so no need to acquire dev->dev_status_lock again while
executing se_task submission.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:53:29 +00:00
Nicholas Bellinger beb55a0cc1 target: Remove __transport_execute_tasks() for each processing context
This patch removes the original usage of __transport_execute_tasks() ahead
of every transport_get_cmd_from_queue() call in transport_processing_thread().
This helps reduce se_device->execute_task_lock contention between qla2xxx wq
with target_submit_cmd() for READs and transport_processing_thread()
context servicing WRITEs with full payloads for I/O submission.

It also adds a __transport_execute_tasks() to kick the task queue again
without a *se_cmd descriptor with existing queue full logic, but this may
end up not being necessary.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:50:12 +00:00
Nicholas Bellinger 4d2300ccff target: Remove extra se_device->execute_task_lock access in fast path
This patch makes __transport_execute_tasks() perform the addition of
tasks to dev->execute_task_list via __transport_add_tasks_from_cmd()
while holding dev->execute_task_lock during normal I/O fast path
submission.

It effectively removes the unnecessary re-acquire of dev->execute_task_lock
during transport_execute_tasks() -> transport_add_tasks_from_cmd() ahead
of calling  __transport_execute_tasks() to queue tasks for the passed
*se_cmd descriptor.

(v2: Re-add goto check_depth usage for multi-task submission for now..)

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:48:46 +00:00
Nicholas Bellinger 65586d51e0 target: Drop se_device TCQ queue_depth usage from I/O path
Historically, pSCSI devices have been the ones that required target-core
to enforce a per se_device->depth_left.  This patch changes target-core
to no longer (by default) enforce a per se_device->depth_left or sleep in
transport_tcq_window_closed() when we out of queue slots for all backend
export cases.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:42:13 +00:00
Nicholas Bellinger 40be67f4c5 target: Fix possible NULL pointer with __transport_execute_tasks
This patch makes __transport_execute_tasks() use a local *se_dev
reference to prevent direct se_cmd->se_dev access after
transport_cmd_check_stop() -> transport_add_tasks_from_cmd()
has been called, as in the current implementation we can expect
__transport_execute_tasks() may be called from another context
that may have already completed the I/O.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:42:12 +00:00
Nicholas Bellinger a636078552 target: Add target_submit_cmd() for process context fabric submission
This patch adds a target_submit_cmd() caller that can be used by fabrics
to submit an uninitialized se_cmd descriptor to an struct se_session +
unpacked_lun from workqueue process context.  This call will invoke the
following steps:

- transport_init_se_cmd() to setup se_cmd specific pointers
- Obtain se_cmd->cmd_kref references with target_get_sess_cmd()
- set se_cmd->t_tasks_bidi
- transport_lookup_cmd_lun() to setup struct se_cmd->se_lun from
  the passed unpacked_lun
- transport_generic_allocate_tasks() to setup the passed *cdb, and
- transport_handle_cdb_direct() handle READ dispatch or WRITE
  ready-to-transfer callback to fabric

v2 changes from hch feedback:

*) Add target_sc_flags_table for target_submit_cmd flags
*) Rename bidi parameter to flags, add TARGET_SCF_BIDI_OP
*) Convert checks to BUG_ON
*) Add out_check_cond for transport_send_check_condition_and_sense
   usage

v3 changes:

*) Add TARGET_SCF_ACK_KREF for target_submit_cmd into
   target_get_sess_cmd to determine when the fabric caller is expecting
   a second kref_put() from fabric packet acknowledgement.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:40:56 +00:00
Nicholas Bellinger 7481deb413 target: Make target_put_sess_cmd use target_release_cmd_kref
This patch moves target_put_sess_cmd() to use a se_cmd->cmd_kref
callback target_release_cmd_kref when performing driver release of
fabric->se_cmd descriptor memory.  It sets the default cmd_kref
count value to '2' within target_get_sess_cmd() setup, and
currently assumes TFO->check_stop_free() usage.

It drops se_tfo->check_release_cmd() usage in the main
transport_release_cmd codepath.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:38:29 +00:00
Jörn Engel 8359cf43b9 target: remove useless casts
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: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:28:07 +00:00
Christoph Hellwig 1880807adb target: make the se_task task_state_active a normal bool
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:27:02 +00:00
Christoph Hellwig 41e16e9816 target: remove the se_task task_error_status field
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:26:44 +00:00
Christoph Hellwig ef804a849f target: fold se_task.task_sense into task_flags
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:26:27 +00:00
Christoph Hellwig c4795fb20e target: header reshuffle, part2
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:26:05 +00:00
Christoph Hellwig e26d99aed4 target: reshuffle headers
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 08:51:12 +00:00
Jörn Engel 5c73b678f7 target: remove unused struct fields
Some are never used, some are set but never read, dev_hoq_count is
incremented and decremented, but never read.

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:56 +00:00
Roland Dreier 9b5cd7f37e target: Handle 0 correctly in transport_get_sectors_6()
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: Roland Dreier <roland@purestorage.com>
Cc: stable@kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:55 +00:00
Roland Dreier 410f670202 target: Don't return an error status for 0-length READ and WRITE
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: Roland Dreier <roland@purestorage.com>
Cc: stable@kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:55 +00:00
Nicholas Bellinger fef58a6096 target: Reject SCSI data overflow for fabrics using transport_generic_map_mem_to_cmd
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: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:53 +00:00
Christoph Hellwig 33c3fafc43 target: remove the t_tasks_bidi se_cmd field
And use a SCF_BIDI flag instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:53 +00:00
Christoph Hellwig 2d3a4b51df target: remove the t_tasks_fua se_cmd field
And use a SCF_FUA flag instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:52 +00:00
Christoph Hellwig aad13ca20d target: remove the se_ordered_node se_cmd field
We never walk ordered_cmd_list in the se_device, so remove all code related
to supporting it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:52 +00:00
Christoph Hellwig 58a2801a4b target: remove the se_obj_ptr and se_orig_obj_ptr se_cmd fields
We already have a perfectly valid se_device pointer in the command, so
remove the mostly useless duplicates.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:52 +00:00
Roland Dreier 97c34f3b04 target: Get rid of unused se_cmd_cache
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:51 +00:00
Bart Van Assche 330694a50f target: Improve system responsivity during I/O
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: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:50 +00:00
Nicholas Bellinger 03e98c9eb9 target: Address legacy PYX_TRANSPORT_* return code breakage
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: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06 06:00:49 +00:00
Linus Torvalds 32aaeffbd4 Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h
2011-11-06 19:44:47 -08:00
Christoph Hellwig 5bda90c8f2 target: use ->exectute_task for all CDB emulation
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-11-04 10:44:35 +00:00
Christoph Hellwig d29a5b6acc target: remove SCF_EMULATE_CDB_ASYNC
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-11-04 10:43:35 +00:00
Christoph Hellwig e76a35d6c8 target: pass the se_task to the CDB emulation callback
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-11-04 08:00:17 +00:00
Christoph Hellwig 617c0e06c1 target: split core_scsi3_emulate_pr
Split core_scsi2_emulate_crh into one routine each for the
PERSISTENT_RESERVE_IN and PERSISTENT_RESERVE_OUT side.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-11-04 08:00:17 +00:00
Christoph Hellwig eacac00ce5 target: split core_scsi2_emulate_crh
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-11-04 08:00:08 +00:00
Nicholas Bellinger a17f091d1a target: Add generic active I/O shutdown logic
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: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-11-04 07:50:26 +00:00
Christoph Hellwig 2235007c4d target: add back error handling in transport_complete_task
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-11-02 16:21:10 +00:00
Nicholas Bellinger 3151d069e9 target: Remove core TRANSPORT_FREE_CMD_INTR usage
This patch drops TRANSPORT_FREE_CMD_INTR usage from target core, which
includes the removal of transport_generic_free_cmd_intr() symbol,
TRANSPORT_FREE_CMD_INTR usage in transport_processing_thread(), and
special case LUN_RESET handling to skip TRANSPORT_FREE_CMD_INTR processing
in core_tmr_drain_cmd_list().  We now expect that fabric modules will
use an internal workqueue to provide process context when releasing
se_cmd descriptor resources via transport_generic_free_cmd().

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Madhuranath Iyengar <mni@risingtidesystems.com>
Signed-off-by: Nicholas Bellinger <nab@risingtidesystems.com>
2011-11-02 15:58:46 +00:00
Nicholas Bellinger 88dd9e26d6 target: Make TFO->check_stop_free return free status
This patch converts target_core_fabric_ops->check_stop_free() usage in
transport_cmd_check_stop() and associated fabric module usage to
return '1' when the passed se_cmd has been released directly within
->check_stop_free(), or return '0' when the passed se_cmd has not
been released.

This addresses an issue where transport_cmd_finish_abort() ->
transport_cmd_check_stop_to_fabric() was leaking descriptors during
LUN_RESET for modules using ->check_stop_free(), but not directly
releasing se_cmd in all cases.

Cc: stable@kernel.org
Signed-off-by: Nicholas Bellinger <nab@risingtidesystems.com>
2011-11-02 15:58:30 +00:00
Paul Gortmaker 827509e38e drivers/target: Add module.h to drivers/target files as required.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:31:59 -04:00
Nicholas Bellinger f147abb475 target: Check -ENOMEM to signal QUEUE_FULL from fabric callbacks
This patch changes target core to also check for -ENOMEM from fabric callbacks
to signal QUEUE_FULL status, instead of just -EAGAIN in order to catch a
larger set of fabric failure cases that want to trigger QUEUE_FULL logic.
This includes the callbacks for ->write_pending(), ->queue_data_in() and
->queue_status().

It also makes transport_generic_write_pending() return zero upon QUEUE_FULL,
and removes two unnecessary -EAGAIN checks to catch write pending QUEUE_FULL
cases from transport_generic_new_cmd() failures in transport_handle_cdb_direct()
and transport_processing_thread():TRANSPORT_NEW_CMD_MAP state.

Reported-by: Bart Van Assche <bvanassche@acm.org>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-10-27 01:00:06 +00:00
Nicholas Bellinger 2e982ab92d target: Remove legacy se_task->task_timer and associated logic
This patch removes the legacy usage of se_task->task_timer and associated
infrastructure that originally was used as a way to help manage buggy backend
SCSI LLDs that in certain cases would never return back an outstanding task.

This includes the removal of target_complete_timeout_work(), timeout logic
from transport_complete_task(), transport_task_timeout_handler(),
transport_start_task_timer(), the per device task_timeout configfs attribute,
and all task_timeout associated structure members and defines in
target_core_base.h

This is being removed in preparation to make transport_complete_task() run
in lock-less mode.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:22:08 +00:00
Nicholas Bellinger 415a090ade target: Fix incorrect transport_sent usage
This patch converts target-core to use se_cmd->t_transport_sent instead of
a duplicated se_cmd->transport_sent member in a handful of locations.
It also updates iscsi_target to properly use ->t_transport_sent instead of
it's own iscsi_cmd_t->transport_sent value that was not being assigned.

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:22:06 +00:00
Christoph Hellwig af3f00c759 target: re-use the command S/G list for single-task commands
If we only have a single task per command (which at least in my testing
is the by far most common case) we do not have to allocate a new per-task
S/G list but can reuse the one from the command.

(nab: Fix BIDI handling in transport_free_dev_tasks)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:22:04 +00:00
Nicholas Bellinger 9ac549873d target: Fix BIDI t_task_cdb handling in transport_generic_new_cmd
This patch fixes a bug for BIDI handling in transport_generic_new_cmd() where
cmd->t_task_cdbs_left and Co. where not taking into account the extra
task count generated during the first call to transport_allocate_data_tasks().

Cc: Christoph Hellwig <hch@lst.de>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:22:02 +00:00
Christoph Hellwig 38b400676b target: remove transport_allocate_tasks
There were only two callers, and one of them always wants the call
to transport_allocate_data_tasks anyway.  Also drop the constant
lba argument to transport_allocate_data_tasks and move the variables
inside it into the minimum required scope.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:59 +00:00
Christoph Hellwig da0f761991 target: merge transport_new_cmd_obj into transport_generic_new_cmd
These are two fairly small functions, and merging them gives a much
more readable control flow, and opportunities for more useful comments.

It also moves all code related to resources allocation closer together
and allows to remove a forward declaration for transport_allocate_tasks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:57 +00:00
Christoph Hellwig 7c1c6af37a target: remove the task_sg_bidi field se_task and pSCSI BIDI support
This field is never used given that BIDI handling happens at the
command and not the task level.  Remove it and the dead code in
pscsi that tries to work on it.

It also prevents pSCSI passthrough for the two currently enabled BIDI
commands now that task->task_sg_bidi support has been removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:56 +00:00
Nicholas Bellinger dbc5623eb2 target: transport_subsystem_check_init cleanups
Remove the now unnecessary extra call to transport_subsystem_check_init() in
target_core_register_fabric(), and also merge transport_subsystem_reqmods()
directly into transport_subsystem_check_init().

Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:54 +00:00
Christoph Hellwig 35e0e75753 target: use a workqueue for I/O completions
Instead of abusing the target processing thread for offloading I/O
completion in the backends to user context add a new workqueue.  This means
completions can be processed as fast as available CPU time allows it,
including in parallel with other completions and more importantly I/O
submission or QUEUE FULL retries.  This should give much better performance
especially on loaded systems.

As a fallout we can merge all the completed states into a single
one.

On the downside this change complicates lun reset handling a bit by
requiring us to cancel a work item only for those states that have it
initialized.  The alternative would be to either always initialize the work
item to a dummy handler, or always use the same handler and do a switch on
the state. The long term solution will be a flag that says that the command
has an initialized work item, but that's only going to be useful once we
have more users.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:52 +00:00
Christoph Hellwig f2da9dbdb5 target: remove TRANSPORT_DEFERRED_CMD state
We never check for this state, and it makes testing for a completed
state much harder given that it overrides the existing state.

Also remove the unused deferred_t_state which is related to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:49 +00:00
Christoph Hellwig bfaf40ada2 target: remove the TRANSPORT_REMOVE state
We never queue an command with this state, and only set it in a completely
bogus place in tcm_fc.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:47 +00:00
Christoph Hellwig 4499dda858 target: move depth_left manipulation out of transport_generic_request_failure
We only need to decrement dev->depth_left if failing a command from
__transport_execute_tasks.  Instead of doing it first thing in
transport_generic_request_failure and requiring a pseudo-flag argument
for it just opencode the decrement in the two callers (which should
be factored into a single one anyway)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:46 +00:00
Christoph Hellwig cc5d0f0f61 target: stop task timers earlier
Currently we stop the timers for all tasks in a command fairly late during
I/O completion, which is fairly pointless and requires all kinds of safety
checks.

Instead delete pending timers early on in transport_complete_task, thus
ensuring no new timers firest after that.  We take t_state_lock a bit later
in that function thus making sure currenly running timers are out of the
criticial section.  To be completely sure the timer has finished we also
add another del_timer_sync call when freeing the task.

This also allows removing TF_TIMER_RUNNING as it would be equivalent
to TF_ACTIVE now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:21:44 +00:00