Convert to use O_DSYNC for all cases at FILEIO backend creation time to
avoid the extra syncing of pure timestamp updates with legacy O_SYNC during
default operation as recommended by hch. Continue to do this independently of
Write Cache Enable (WCE) bit, as WCE=0 is currently the default for all backend
devices and enabled by user on per device basis via attrib/emulate_write_cache.
This patch drops the now unnecessary fd_buffered_io= token usage that was
originally signalling when to explictly disable O_SYNC at backend creation
time for buffered I/O operation. This can end up being dangerous for a number
of reasons during physical node failure, so go ahead and drop this option
for now when O_DSYNC is used as the default.
Also allow explict FUA WRITEs -> vfs_fsync_range() call to function in
fd_execute_cmd() independently of WCE bit setting.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
'int login_id' shadows 'static atomic_t login_id'.
Seen as compilation warning on x86-32.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Pull sbp-2 (firewire) target mode support from Nicholas Bellinger:
"The FireWire SBP-2 Target is a driver for using an IEEE-1394
connection as a SCSI transport. This module uses the SCSI Target
framework to expose LUNs to other machines attached to a FireWire bus,
in effect acting as a FireWire hard disk similar to FireWire Target
Disk mode on many Apple computers.
Also included are the two drivers/firewire/ patches required by
sbp-target to access fw_request fabric speed needed for mgt_agent
TCODE_WRITE_BLOCK_REQUEST ops, and exporting fw_card kref logic used
when creating/destroying active session references to individual
endpoints.
A credit goes to Chris in being able to get this code up and running
so quickly w/o any target core changes, and special thanks goes out to
Stefan Richter + Clemens Ladisch + Andy Grover for their help in
getting this driver ready for mainline. Also, one of Chris's goals
was to be able to connect sbp-target to a PowerPC based MacOS-X based
client, that he accomplished along the way in this obligatory
screenshot:
http://linux-iscsi.org/wiki/File:Linux-fireware-target-bootc-macosx.png
Great work Chris + linux-1394 team !!"
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
* 'sbp-target-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
sbp-target: Initial merge of firewire/ieee-1394 target mode support
firewire: Move fw_card kref functions into linux/firewire.h
firewire: Add function to get speed from opaque struct fw_request
Pull scsi-target changes from Nicholas Bellinger:
"There has been lots of work in existing code in a number of areas this
past cycle. The major highlights have been:
* Removal of transport_do_task_sg_chain() from core + fabrics
(Roland)
* target-core: Removal of se_task abstraction from target-core and
enforce hw_max_sectors for pSCSI backends (hch)
* Re-factoring of iscsi-target tx immediate/response queues (agrover)
* Conversion of iscsi-target back to using target core memory
allocation logic (agrover)
We've had one last minute iscsi-target patch go into for-next to
address a nasty regression bug related to the target core allocation
logic conversion from agrover that is not included in friday's
linux-next build, but has been included in this series.
On the new fabric module code front for-3.5, here is a brief status
update for the three currently in flight this round:
* usb-gadget target driver:
Sebastian Siewior's driver for supporting usb-gadget target mode
operation. This will be going out as a separate PULL request from
target-pending/usb-target-merge with subsystem maintainer ACKs. There
is one minor target-core patch in this series required to function.
* sbp ieee-1394/firewire target driver:
Chris Boot's driver for supportting the Serial Block Protocol (SBP)
across IEEE-1394 Firewire hardware. This will be going out as a
separate PULL request from target-pending/sbp-target-merge with two
additional drivers/firewire/ patches w/ subsystem maintainer ACKs.
* qla2xxx LLD target mode infrastructure changes + tcm_qla2xxx:
The Qlogic >= 24xx series HW target mode LLD infrastructure patch-set
and tcm_qla2xxx fabric driver. Support for FC target mode using
qla2xxx LLD code has been officially submitted by Qlogic to James
below, and is currently outstanding but not yet merged into
scsi.git/for-next..
[PATCH 00/22] qla2xxx: Updates for scsi "misc" branch
http://www.spinics.net/lists/linux-scsi/msg59350.html
Note there are *zero* direct dependencies upon this for-next series
for the qla2xxx LLD target + tcm_qla2xxx patches submitted above, and
over the last days the target mode team has been tracking down an
tcm_qla2xxx specific active I/O shutdown bug that appears to now be
almost squashed for 3.5-rc-fixes."
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (47 commits)
iscsi-target: Fix iov_count calculation bug in iscsit_allocate_iovecs
iscsi-target: remove dead code in iscsi_check_valuelist_for_support
target: Handle ATA_16 passthrough for pSCSI backend devices
target: Add MI_REPORT_TARGET_PGS ext. header + implict_trans_secs attribute
target: Fix MAINTENANCE_IN service action CDB checks to use lower 5 bits
target: add support for the WRITE_VERIFY command
target: make target_put_session void
target: cleanup transport_execute_tasks()
target: Remove max_sectors device attribute for modern se_task less code
target: lock => unlock typo in transport_lun_wait_for_tasks
target: Enforce hw_max_sectors for SCF_SCSI_DATA_SG_IO_CDB
target: remove the t_se_count field in struct se_cmd
target: remove the t_task_cdbs_ex_left field in struct se_cmd
target: remove the t_task_cdbs_left field in struct se_cmd
target: remove struct se_task
target: move the state and execute lists to the command
target: simplify command to task linkage
target: always allocate a single task
target: replace ->execute_task with ->execute_cmd
target: remove the task_sectors field in struct se_task
...
This patch fixes a bug in iscsit_allocate_iovecs() where iov_count was
incorrectly calculated using min(1UL, data_length / PAGE_SIZE) instead of
max(1UL, data_length / PAGE_SIZE), that ends up triggering an OOPs for
large block I/O when the SGL <-> iovec mapping exceeds the bogus iov_count
allocation size.
This is a regression introduced during the iscsi-target conversion back
to using core memory allocation here:
commit bfb79eac20
Author: Andy Grover <agrover@redhat.com>
Date: Tue Apr 3 15:51:29 2012 -0700
target/iscsi: Go back to core allocating data buffer for cmd
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Neither "acceptor_values" nor "proposer_values" can be NULL here when
scanning the value lists for incoming iSCSI login parameters such as
HeaderDigest=CRC32C,None.
Smatch complains because we are not allowed to pass NULL pointers to
strchr(). Also I removed a second later check for "!acceptor_values"
because it gets checked on the next line in the do while condition.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch fixes a bug in the handling of FILEIO w/ underlying block_device
resize operations where the original fd_dev->fd_dev_size was incorrectly being
used in fd_get_blocks() for READ_CAPACITY response payloads.
This patch avoids using fd_dev->fd_dev_size for FILEIO devices with
an underlying block_device, and instead changes fd_get_blocks() to
get the sector count directly from i_size_read() as recommended by hch.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
The cdrecord uses ATA_PASS_THROUGH_16 command while burning CDs
with a SATA CD-ROM. This patch adds support to it so that PSCSI
CD-ROM passthrough works with the cdrecord.
(nab: Add !passthrough check to prevent non pSCSI backends from ATA_16)
Signed-off-by: Cong Meng <mc@linux.vnet.ibm.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch adds support for ALUA MI_REPORT_TARGET_PGS extended header
format defined within SPC-4. It changes target core ALUA emulation logic
within target_emulate_report_target_port_groups() to support both the
extended and original length only header formats.
It includes adding a new 'implict_trans_secs' attribute for each ALUA
target port group to control the value returned to the application client
for an recommended implict translation timeout in seconds. By default
this value is currently set to zero, and limited up to 255 by virtue of
using a single byte in the extended header format.
This value is used by target_emulate_report_target_port_groups() within
the extended header logic to set IMPLICIT TRANSITION TIME as defined by
spc4r30.
Cc: Hannes Reinecke <hare@suse.de>
Cc: Rob Evers <revers@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch fixes the MAINTENANCE_IN service action type checks to only
look at the proper lower 5 bits of cdb byte 1. This addresses the case
where MI_REPORT_TARGET_PGS w/ extended header using the upper three bits of
cdb byte 1 was not processed correctly in transport_generic_cmd_sequencer,
as well as the three cases for standby, unavailable, and transition ALUA
primary access state checks.
Also add MAINTENANCE_IN to the excluded list in transport_generic_prepare_cdb()
to prevent the PARAMETER DATA FORMAT bits from being cleared.
Cc: Hannes Reinecke <hare@suse.de>
Cc: Rob Evers <revers@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Some legacy OS use WRITE_VERIFY on hard disks.
Signed-off-by: Bernhard Kohl <bernhard.kohl@gmx.net>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch addresses a bug in a special case for target core SPC-2 RELEASE
logic where the same physical client (eg: iSCSI InitiatorName) with
differing iSCSI session identifiers (ISID) is allowed to incorrectly release
the same client's SPC-2 reservation from the non reservation holding path.
Note this bug is specific to iscsi-target w/ SPC-2 reservations, and
with the default enforce_pr_isids=1 device attr setting in target-core
controls if a InitiatorName + different ISID reservations are handled
the same as a single iSCSI client entity.
Signed-off-by: Bernhard Kohl <bernhard.kohl@gmx.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
The function is effectively void and doesn't need any goto logic.
Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch removes some potentially problematic legacy code within
core_clear_initiator_node_from_tpg() that was originally intended to
release left over se_lun_acl setup during dynamic NodeACL+MappedLUN
generate when running with TPG demo-mode operation.
Since we now only ever expect to allocate and release se_lun_acl from
within target_core_fabric_configfs.c:target_fabric_make_mappedlun() and
target_fabric_drop_mappedlun() context respectively, this code for
demo-mode release is incorrect and needs to be removed.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
The FireWire SBP-2 Target is a driver for using an IEEE-1394 connection
as a SCSI transport. This module uses the SCSI Target framework to
expose LUNs to other machines attached to a FireWire bus, in effect
acting as a FireWire hard disk similar to FireWire Target Disk mode
on many Apple computers.
This commit contains the squashed pull from Chris Boot's SBP-2-Target:
https://github.com/bootc/Linux-SBP-2-Target.git patch-v3
firewire-sbp-target: Add sbp_base.h header
firewire-sbp-target: Add sbp_configfs.c
firewire-sbp-target: Add sbp_fabric.{c,h}
firewire-sbp-target: Add sbp_management_agent.{c,h}
firewire-sbp-target: Add sbp_login.{c,h}
firewire-sbp-target: Add sbp_target_agent.{c,h}
firewire-sbp-target: Add sbp_scsi_cmnd.{c,h}
firewire-sbp-target: Add to target Kconfig and Makefile
Also add bootc's entry to the MAINTAINERS file. Great work Chris !!
Signed-off-by: Chris Boot <bootc@bootc.net>
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch removes the original usage of dev_attr->max_sectors in favor of
dev_attr->hw_max_sectors that is now being enforced by target core from
within transport_generic_cmd_sequencer() for SCF_SCSI_DATA_SG_IO_CDB ops.
After the recent se_task removal patches from hch, this value for IBLOCK
backends being set via configfs by userspace from an saved max_sectors
value that is turning out to be problematic, so it makes sense to go ahead
and remove this now legacy attribute all-together.
This patch also continues to make se_dev_set_default_attribs() do
(sectors / block_size) alignment for what actually get used by
target_core_mod to be safe here, following the same alignment currently
used by fabric_max_sectors.
Reported-by: Andy Grover <agrover@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
target_stop_cmd() returns with the lock held and IRQs disabled. The
intent was to unlock here. This bug was originally added with:
commit cf572a9627
Author: Christoph Hellwig <hch@infradead.org>
Date: Tue Apr 24 00:25:05 2012 -0400
target: move the state and execute lists to the command
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Instead of depending upon a max_sectors value that may be set via
configfs based upon original HW queue limitations, go ahead and convert to using
the hw_max_sectors reported by the backend device in order to determine when
to reject an I/O's who's sector count exceeds what is supported by the backend
with a single se_cmd descriptor.
It addresses a potential case where se_dev_attrib.max_sectors for IBLOCK
backends has already been set via queue_max_sectors() to something small
like max_sectors=32 (LVM, DRBD may do this), resulting typically sized
SCF_SCSI_DATA_SG_IO_CDB to be incorrectly rejected with invalid_cdb_field
in transport_generic_cmd_sequencer().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Now that tasks are gone we are guaranteed to only get a single completion
per command, and thus don't need this counter.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Now that tasks are gone we are guaranteed to only get a single completion
per command, and thus don't need this counter.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Now that tasks are gone we are guaranteed to only get a single completion
per command, and thus don't need this counter.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Now that we only have a single task per command we can use a direct pointer
to it instead of list.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Simply transport_generic_new_cmd to only allocate a single task. For normal
unidirection commands nothing changes except that the code is a lot simpler
now. Any BIDI support that used to work will stop now for the next few
patches at least.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Remove the task_sectors field that isn't used anywhere.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Now that tasks are always the same size as the command there is no need
to rewrite a CDB in common code. Notw that we keep the separately allocated
CDB in the pscsi and stgt backends for now, to easy reintroducing any
command splitting local to these backends if nessecary.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
The SCSI MMC GET_EVENT_STATUS_NOTIFICATION command can be used to find
out about media change, among other things. This patch adds it to the
command sequencer so that PSCSI CD-ROM passthrough works with modern
Linux guests that issue this command.
Tested-by: Cong Meng <mengcong@cn.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
We can use kcalloc() here instead of kzalloc(). It's better style and
it has overflow checking built in.
Also -ENOMEM is the correct error code for allocation errors. -1 means
-EPERM. None of the callers preserve the error codes so it doesn't
matter except as a cleanup.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
We originally changed iscsi to allocate its own buffers just as an
intermediate step to clean up some core buffer allocation mechanisms. Now
we can put it back.
Also had to change allocate_iovecs to use data_length instead of
t_data_nents because iovecs are now allocated before the data buffer, thus
t_data_nents is not yet initialized.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
It appears iscsi is the only one to call this in its cmd submit path, but
it appears to be applicable to all fabrics, and should always be called.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Rename iscsit_build_pdu_and_seq_list to iscsit_do_build_pdu_and_seq_lists
Rename iscsit_do_build_list to iscsit_build_pdu_and_seq_lists
Move code from iscsit_decide_list_to_build into _seq_pdu_list.c, seems
a better fit.
Also update some comments in pdu/seq code for correctness and whitespace.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Redundant, just use iscsi_cmd->se_cmd.data_length once se_cmd is
initialized, or hdr->data_length before then.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
if we can get calls to init_se_cmd, get_sess_cmd, lookup_cmd_lun,
core_alua_check_nonop_delay, and handle_cdb_direct next to each other,
then we can just call target_submit_cmd. This is a step towards that
goal.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Trying to move a bunch of stuff around so iscsi can use target_submit_cmd
someday, and so stuff needs to be in that function directly instead of
hidden, so it can be reordered etc.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch renames a horribly misnamed function that no longer allocate
tasks to something more descriptive for it's modern use in target core.
(nab: Fix up ib_srpt to use this as well ahead of a target_submit_cmd
conversion)
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch includes the handful of squashed patches for target/iscsi from
Andy's original series into lio-core/master code:
*) Make iscsit_add_reject static
*) Remove unused data_offset_end from iscsi_datain_req
*) Remove "#if 0" stubs
*) Rename iscsi_datain_req to cmd_datain_node
*) Cleanups for built_r2ts_for_cmd()
*) Cleanups for Cleanup build_sendtargets_response()
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Immediate queue:
Consolidate down to one switch statement by moving send_tx_data and stuff
from second switch into the first switch, or the functions the first switch
calls.
Response queue:
Do not lock istate_lock except directly around i_state modifications.
Put entire ISTATE_SEND_DATAIN path within first switch statement, in prep
for further refactoring.
All other cases set use_misc = 1 and will not be using sendpage, so just
use send_tx_data for these and set use_misc param to 1.
map_sg, sent_status, use_misc, and se_cmd vars no longer needed.
Then put immediate and response handling in separate functions in order
to get iscsi_target_tx_thread down to where it fits on a page.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
When processing immediate queue, we're switching on a local variable
so it's not necessary to lock around it. However, we are modifying
cmd->i_state in two spots, so lock around those parts only.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
*) Use decoded cmd->immediate_cmd for conditional instead of
re-examining hdr->opcode
*) Make iscist_dataout_post_crc_passed more legible
*) use max() to reduce code in build_r2ts_for_cmd()
*) Remove CONFIG_SMP and if 0 ifdefs
*) Replace if/goto with a while loop
*) Remove unused conn->tx_immediate_queue and tx_response_queue
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
The name change makes it clear this list_head is so the cmd can be an
item in the connection's conn_cmd_list.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Now that all fabrics are converted over to using se_cmd->t_data_sg
directly, we can drop the task sg chaining support. With the modern
memory allocation in target core, task sg chaining is needless
overhead -- we would split up the main cmd sglist into pieces, and
then splice those pieces back together instead of just using the
original list directly.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
With the modern target core, se_cmd->t_data_sg already points to a
sglist that covers the whole command. So task_sg chaining is needless
overhead and obfuscation -- instead of splicing the split up task
sglists back into one list, we can just use the original list directly.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Kiran Patil <Kiran.patil@intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
From hch:
The high-performance backends (iblock and rd) support tasks of unlimited
size. With that there is no reason to keep a complex infrastructure for
splitting up commands in place. Stop doing so and only submit a single
task per data direction. Once this is in place we can slowly remove fields
from the task that duplicate things in the command, or move other fields
into the command.
From nab:
The benefit to IBLOCK performance by removing the additional
fast-path allocation overhead + SGL mapping to se_task->task_sg[] is now
greater than transparently supporting an received CDB I/O length that
exceeds what is allowed by backend pSCSI LLD hardware max_sectors, that
was originally supported for all backend export cases.
This change may effect some users of pSCSI users on legacy hardware, but
I think most folks are now using TYPE_DISK struct scsi_device export
with IBLOCK. The only other place where this may can issues that cannot
be resolved with IBLOCK TYPE_DISK is using TYPE_ROM, TYPE_TAPE or other
pSCSI non TYPE_DISK export with an SCSI LLDs using a smaller
max_sectors.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
