scsi_setup_fs_cmnd does not like to receive requests with no
bios attached to it.  Special-case zero-length reads and writes,
by not submitting any bio.

Testcase: sg_raw /dev/sdb 28 00 00 00 00 00 00 00 00 00
    should not fail
    panics with the rest of the series but not this patch
    behaves correctly without or with this series
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch drops se_subsystem_api->[write_cache,fua_write]_emulated flags
set by viritual FILEIO/IBLOCK/RD_MCP backend drivers in favor of explict
TRANSPORT_PLUGIN_PHBA_PDEV checks to know when to fail if userspace is
attempting to set virtual emulation bits for an pSCSI (passthrough)
backend device.
Reported-by: NChristoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Following commit dbc6e022 from Al Viro for fileio, go ahead and make
Opt_udev_path within iblock_set_configfs_dev_params use match_strlcpy
instead of the match_strdup -> snprintf -> kfree equivalent.
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

With the old code, when you allocate a bio from a bio pool you have to
implement your own destructor that knows how to find the bio pool the
bio was originally allocated from.

This adds a new field to struct bio (bi_pool) and changes
bio_alloc_bioset() to use it. This makes various bio destructors
unnecessary, so they're then deleted.

v6: Explain the temporary if statement in bio_put
Signed-off-by: NKent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
CC: Alasdair Kergon <agk@redhat.com>
CC: Nicholas Bellinger <nab@linux-iscsi.org>
CC: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: NTejun Heo <tj@kernel.org>
Acked-by: NNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Several places were not checking that the parameter list length
was large enough, and thus accessing invalid memory.  Zero-length
parameter lists are just a special case of this.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Fail UNMAP commands that have more than our reported limit on unmap
descriptors.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

It's possible for an initiator to send us an UNMAP command with a
descriptor that is less than 8 bytes; in that case it's really bad for
us to set an unsigned int to that value, subtract 8 from it, and then
use that as a limit for our loop (since the value will wrap around to
a huge positive value).

Fix this by making size be signed and only looping if size >= 16 (ie
if we have at least a full descriptor available).

Also remove offset as an obfuscated name for the constant 8.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The UNMAP DATA LENGTH and UNMAP BLOCK DESCRIPTOR DATA LENGTH fields
are in the unmap descriptor (the payload transferred to our data out
buffer), not in the CDB itself.  Read them from the correct place in
target_emulated_unmap.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

When processing an UNMAP command, we need to make sure that the number
of blocks we're asked to UNMAP does not exceed our reported maximum
number of blocks per UNMAP, and that the range of blocks we're
unmapping doesn't go past the end of the device.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Having all the unmap payload parsing in the backed is a bit ugly, but until
more drivers support it and we can find a good interface for all of them
that seems the way to go.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Add spc_ops->execute_write_same() caller for ->execute_cmd() setup,
and update IBLOCK backends to use it.

(nab: add export of spc_get_write_same_sectors symbol)
(roland: Carry forward: Fix range calculation in WRITE SAME emulation
         when num blocks == 0)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Add spc_ops->execute_sync_cache() caller for ->execute_cmd() setup,
and update IBLOCK + FILEIO backends to use it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Remove the execute_cmd method in struct se_subsystem_api, and always use the
one directly in struct se_cmd.  To make life simpler for SBC virtual backends
a struct spc_ops that is passed to sbc_parse_cmd is added.  For now it
only contains an execute_rw member, but more will follow with the subsequent
commits.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

see https://bugzilla.redhat.com/show_bug.cgi?id=818855

Adds a parameter so read-only block devices may be registered as
LIO backstores.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Instead of trying to handle all SCSI command sets in one function
(transport_generic_cmd_sequencer) call out to the backend driver to perform
this functionality.  For pSCSI a copy of the existing code is used, but for
all virtual backends we can use a new parse_sbc_cdb helper is used to
provide a simple SBC emulation.

For now this setups means a fair amount of duplication between pSCSI and the
SBC library, but patches later in this series will sort out that problem.

(nab: Fix up build failure in target_core_pscsi.c)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We can use struct se_cmd for everything it did.  Make sure to pass the S/G
list and data direction to the execution function to ease adding back BIDI
support later on.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Make CDB emulation work on commands instead of tasks again as a preparation
of removing tasks completely.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Now that we don't split commands the size field in the task is always
equivalent to the one in the CDB, even in cases where we have two tasks
due to a BIDI transfer.  Just refer the the size in the command instead
of duplicating it in the task.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Now that we don't split commands the lba field in the task is always
equivalent to the one in the CDB, even in cases where we have two tasks
due to a BIDI transfer.  Just refer the the lba in the command instead
of duplicating it in the task.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

There is no real limit for task sizes in the iblock driver given that we
can chain bios.  Increase the maximum size to UINT_MAX, and change the
code to submit bios in a smaller batch size to avoid deadlocks when
having more bios in flight than the pool supports.  Also increase the
pool size to always allow multiple tasks to be in flight.

I also had to change the task refcounting to include one reference for
the submission task, which is a standard practice in this kind of code
in Linux (e.g. XFS I/O submission).  This was wrong before, but couldn't
be hit easily.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

There is no reason to allocate a struct just to store the host number for
a debug printk in the detach path.  I've simply removed the verbose
debugging given that the calling code thinks the number passed in is
something different from a host ID anyway.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Requesting to many bvecs upsets bio_alloc_bioset, so limit the number we ask
for to the amount it can handle.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The block layer keeps q->limits.discard_granularity in bytes, but iblock
(and the SCSI Block Limits VPD page) keep unmap_granularity in blocks.
Report the correct value when exporting block devices by dividing to
convert bytes to blocks.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We never embedd the bio into a structure, so there is no need to allocate
64 bytes of headroom per bio.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

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>

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>

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>

And use a SCF_FUA flag instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
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>

Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Remove the dpo_emulated, fua_write_emulated, fua_read_emulated and
write_cache_emulated methods, and replace them with a simple bitfields in
se_subsystem_api in those cases where they ever returned one.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Do not block the submitting thread when handling a SYNCHRONIZE CACHE command,
but implement it asynchronously by sending the FLUSH command ourself and
calling transport_complete_sync_cache from the completion handler.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The most commonly used file, iblock and rd backends have no use for
a per-task CDB and thus don't need a method to copy it into their
otherwise unused CDB fields.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This is a squashed version of the following se_task cleanup patches:

    target: remove the unused task_state_flags field in se_task
    target: remove the unused se_obj_ptr field in se_task
    target: remove the se_dev field in se_task
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Move the entirely bio allocation, mapping and submission into ->do_task.
This

 a) avoids blocking the I/O submission thread unessecarily, and
 b) simplifies the code greatly
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

It was pointed out by 'make versioncheck' that some includes of
linux/version.h are not needed in drivers/target/.
This patch removes them.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

It was pointed out by 'make versioncheck' that some includes of
linux/version.h are not needed in drivers/target/.
This patch removes them.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

This patch breaks up the ->map_task_SG() backend call into two seperate
->map_control_SG() and ->map_data_SG() in order to better address
IBLOCK and pSCSI.  IBLOCK only allocates bios for ->map_data_SG(), and
pSCSI will allocate a struct request for both cases.

This patch fixes incorrect usage of ->map_task_SG() for all se_cmd descriptors
in transport_generic_new_cmd() by moving the call into it's proper location
directly inside of transport_allocate_data_tasks()
Reported-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch contains the squashed version of forth round series cleanups
from Andy and Christoph following the post heavy lifting in the preceeding:
'Eliminate usage of struct se_mem' and 'Make all control CDBs scatter-gather'
changes.  This also includes a conversion of target core and the v3.0
mainline fabric modules (loopback and tcm_fc) to use pr_debug and the
CONFIG_DYNAMIC_DEBUG infrastructure!

These have been squashed into this third and final round for v3.1.

target: Remove ifdeffed code in t_g_process_write
target: Remove direct ramdisk code
target: Rename task_sg_num to task_sg_nents
target: Remove custom debug macros for pr_debug. Use pr_err().
target: Remove custom debug macros in mainline fabrics
target: Set WSNZ=1 in block limits VPD. Abort if WRITE_SAME sectors = 0
target: Remove transport do_se_mem_map callback
target: Further simplify transport_free_pages
target: Redo task allocation return value handling
target: Remove extra parentheses
target: change alloc_task call to take *cdb, not *cmd

(nab: Fix bogus struct file assignments in fd_do_readv and fd_do_writev)
Signed-off-by: NAndy Grover <agrover@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Both backstores and fabrics use arrays of struct scatterlist to describe
data buffers. However TCM used struct se_mems, basically a linked list
of scatterlist entries. We are able to simplify the code by eliminating
this intermediate data structure and just using struct scatterlist[]
throughout.

Also, moved attachment of task to cmd out of transport_generic_get_task
and into allocate_control_task and allocate_data_tasks. The reasoning
is that it's nonintuitive that get_task should automatically add it to
the cmd's task list -- it should just return an allocated, initialized
task. That's all it should do, based on the function's name, so either the
function shouldn't do it, or the name should change to encapsulate the
entire essence of what it does.

(nab: Fix compile warnings in tcm_fc, and make transport_kmap_first_data_page
 honor sg->offset for SGLs from contigious memory with TCM_Loop, and
 fix control se_cmd descriptor memory leak)
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>