scsi: usb: Rename the RESERVE and RELEASE constants

The names RESERVE and RELEASE are not only used in <scsi/scsi_proto.h> but
also elsewhere in the kernel:

$ git grep -nHE 'define[[:blank:]]*(RESE

scsi: usb: Rename the RESERVE and RELEASE constants

The names RESERVE and RELEASE are not only used in <scsi/scsi_proto.h> but
also elsewhere in the kernel:

$ git grep -nHE 'define[[:blank:]]*(RESERVE|RELEASE)[[:blank:]]'
drivers/input/joystick/walkera0701.c:13:#define RESERVE 20000
drivers/s390/char/tape_std.h:56:#define RELEASE 0xD4 /* 3420 NOP, 3480 REJECT */
drivers/s390/char/tape_std.h:58:#define RESERVE 0xF4 /* 3420 NOP, 3480 REJECT */

Additionally, while the names of the symbolic constants RESERVE_10 and
RELEASE_10 include the command length, the command length is not included
in the RESERVE and RELEASE names. Address both issues by renaming the
RESERVE and RELEASE constants into RESERVE_6 and RELEASE_6 respectively.

Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Bart Van Assche <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: Fix null-ptr-deref in target_alloc_device()

There is a null-ptr-deref issue reported by KASAN:

BUG: KASAN: null-ptr-deref in target_alloc_device+0xbc4/0xbe0 [target_core_mod]
..

scsi: target: core: Fix null-ptr-deref in target_alloc_device()

There is a null-ptr-deref issue reported by KASAN:

BUG: KASAN: null-ptr-deref in target_alloc_device+0xbc4/0xbe0 [target_core_mod]
...
kasan_report+0xb9/0xf0
target_alloc_device+0xbc4/0xbe0 [target_core_mod]
core_dev_setup_virtual_lun0+0xef/0x1f0 [target_core_mod]
target_core_init_configfs+0x205/0x420 [target_core_mod]
do_one_initcall+0xdd/0x4e0
...
entry_SYSCALL_64_after_hwframe+0x76/0x7e

In target_alloc_device(), if allocing memory for dev queues fails, then
dev will be freed by dev->transport->free_device(), but dev->transport
is not initialized at that time, which will lead to a null pointer
reference problem.

Fixing this bug by freeing dev with hba->backend->ops->free_device().

Fixes: 1526d9f10c61 ("scsi: target: Make state_list per CPU")
Signed-off-by: Wang Hai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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move asm/unaligned.h to linux/unaligned.h

asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-

move asm/unaligned.h to linux/unaligned.h

asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.

auto-generated by the following:

for i in `git grep -l -w asm/unaligned.h`; do
sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h

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scsi: target: Remove unused list 'device_list'

Commit be50f538e9a5 ("target: remove g_device_list") made 'g_device_list'
local as 'device_list' but also removed the last use of it, the code that
add

scsi: target: Remove unused list 'device_list'

Commit be50f538e9a5 ("target: remove g_device_list") made 'g_device_list'
local as 'device_list' but also removed the last use of it, the code that
added the device to it.

Build tested only.

Signed-off-by: Dr. David Alan Gilbert <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: Add TMF to tmr_list handling

An abort that is responded to by iSCSI itself is added to tmr_list but does
not go to target core. A LUN_RESET that goes through tmr_list takes a
ref

scsi: target: core: Add TMF to tmr_list handling

An abort that is responded to by iSCSI itself is added to tmr_list but does
not go to target core. A LUN_RESET that goes through tmr_list takes a
refcounter on the abort and waits for completion. However, the abort will
be never complete because it was not started in target core.

Unable to locate ITT: 0x05000000 on CID: 0
Unable to locate RefTaskTag: 0x05000000 on CID: 0.
wait_for_tasks: Stopping tmf LUN_RESET with tag 0x0 ref_task_tag 0x0 i_state 34 t_state ISTATE_PROCESSING refcnt 2 transport_state active,stop,fabric_stop
wait for tasks: tmf LUN_RESET with tag 0x0 ref_task_tag 0x0 i_state 34 t_state ISTATE_PROCESSING refcnt 2 transport_state active,stop,fabric_stop
...
INFO: task kworker/0:2:49 blocked for more than 491 seconds.
task:kworker/0:2 state:D stack: 0 pid: 49 ppid: 2 flags:0x00000800
Workqueue: events target_tmr_work [target_core_mod]
Call Trace:
__switch_to+0x2c4/0x470
_schedule+0x314/0x1730
schedule+0x64/0x130
schedule_timeout+0x168/0x430
wait_for_completion+0x140/0x270
target_put_cmd_and_wait+0x64/0xb0 [target_core_mod]
core_tmr_lun_reset+0x30/0xa0 [target_core_mod]
target_tmr_work+0xc8/0x1b0 [target_core_mod]
process_one_work+0x2d4/0x5d0
worker_thread+0x78/0x6c0

To fix this, only add abort to tmr_list if it will be handled by target
core.

Signed-off-by: Dmitry Bogdanov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: Allow userspace to request direct submissions

This allows userspace to request the fabric drivers do direct submissions
if they support it. With the new device file, submit_type, users

scsi: target: Allow userspace to request direct submissions

This allows userspace to request the fabric drivers do direct submissions
if they support it. With the new device file, submit_type, users can
write 0 - 2 to control how commands are submitted to the backend:

0 - TARGET_FABRIC_DEFAULT_SUBMIT - LIO will use the fabric's default
submission type. This is the default for compat.

1 - TARGET_DIRECT_SUBMIT - LIO will submit the cmd to the backend from the
calling context if the fabric the cmd was received on supports it,
else it will use the fabric's default type.

2 - TARGET_QUEUE_SUBMIT - LIO will queue the cmd to the LIO submission
workqueue which will pass it to the backend.

When using an NVMe drive and vhost-scsi with direct submission we see
around a 20% improvement in 4K I/Os:

fio jobs 1 2 4 8 10
--------------------------------------------------
defer 94K 190K 394K 770K 890K
direct 128K 252K 488K 950K -

And when using the queueing mode, we now no longer see issues like where
the iSCSI tx thread is blocked in the block layer waiting on a tag so it
can't respond to a nop or perform I/Os for other LUs.

Signed-off-by: Mike Christie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: Fix deadlock due to recursive locking

The following call trace shows a deadlock issue due to recursive locking of
mutex "device_mutex". First lock acquire is in target_for_each_d

scsi: target: core: Fix deadlock due to recursive locking

The following call trace shows a deadlock issue due to recursive locking of
mutex "device_mutex". First lock acquire is in target_for_each_device() and
second in target_free_device().

PID: 148266 TASK: ffff8be21ffb5d00 CPU: 10 COMMAND: "iscsi_ttx"
#0 [ffffa2bfc9ec3b18] __schedule at ffffffffa8060e7f
#1 [ffffa2bfc9ec3ba0] schedule at ffffffffa8061224
#2 [ffffa2bfc9ec3bb8] schedule_preempt_disabled at ffffffffa80615ee
#3 [ffffa2bfc9ec3bc8] __mutex_lock at ffffffffa8062fd7
#4 [ffffa2bfc9ec3c40] __mutex_lock_slowpath at ffffffffa80631d3
#5 [ffffa2bfc9ec3c50] mutex_lock at ffffffffa806320c
#6 [ffffa2bfc9ec3c68] target_free_device at ffffffffc0935998 [target_core_mod]
#7 [ffffa2bfc9ec3c90] target_core_dev_release at ffffffffc092f975 [target_core_mod]
#8 [ffffa2bfc9ec3ca0] config_item_put at ffffffffa79d250f
#9 [ffffa2bfc9ec3cd0] config_item_put at ffffffffa79d2583
#10 [ffffa2bfc9ec3ce0] target_devices_idr_iter at ffffffffc0933f3a [target_core_mod]
#11 [ffffa2bfc9ec3d00] idr_for_each at ffffffffa803f6fc
#12 [ffffa2bfc9ec3d60] target_for_each_device at ffffffffc0935670 [target_core_mod]
#13 [ffffa2bfc9ec3d98] transport_deregister_session at ffffffffc0946408 [target_core_mod]
#14 [ffffa2bfc9ec3dc8] iscsit_close_session at ffffffffc09a44a6 [iscsi_target_mod]
#15 [ffffa2bfc9ec3df0] iscsit_close_connection at ffffffffc09a4a88 [iscsi_target_mod]
#16 [ffffa2bfc9ec3df8] finish_task_switch at ffffffffa76e5d07
#17 [ffffa2bfc9ec3e78] iscsit_take_action_for_connection_exit at ffffffffc0991c23 [iscsi_target_mod]
#18 [ffffa2bfc9ec3ea0] iscsi_target_tx_thread at ffffffffc09a403b [iscsi_target_mod]
#19 [ffffa2bfc9ec3f08] kthread at ffffffffa76d8080
#20 [ffffa2bfc9ec3f50] ret_from_fork at ffffffffa8200364

Fixes: 36d4cb460bcb ("scsi: target: Avoid that EXTENDED COPY commands trigger lock inversion")
Signed-off-by: Junxiao Bi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

show more ...

scsi: target: Replace all non-returning strlcpy() with strscpy()

strlcpy() reads the entire source buffer first. This read may exceed the
destination size limit. This is both inefficient and can l

scsi: target: Replace all non-returning strlcpy() with strscpy()

strlcpy() reads the entire source buffer first. This read may exceed the
destination size limit. This is both inefficient and can lead to linear
read overflows if a source string is not NUL-terminated [1]. In an effort
to remove strlcpy() completely [2], replace strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

show more ...

scsi: target: Fix multiple LUN_RESET handling

This fixes a bug where an initiator thinks a LUN_RESET has cleaned up
running commands when it hasn't. The bug was added in commit 51ec502a3266
("target

scsi: target: Fix multiple LUN_RESET handling

This fixes a bug where an initiator thinks a LUN_RESET has cleaned up
running commands when it hasn't. The bug was added in commit 51ec502a3266
("target: Delete tmr from list before processing").

The problem occurs when:

1. We have N I/O cmds running in the target layer spread over 2 sessions.

2. The initiator sends a LUN_RESET for each session.

3. session1's LUN_RESET loops over all the running commands from both
sessions and moves them to its local drain_task_list.

4. session2's LUN_RESET does not see the LUN_RESET from session1 because
the commit above has it remove itself. session2 also does not see any
commands since the other reset moved them off the state lists.

5. sessions2's LUN_RESET will then complete with a successful response.

6. sessions2's inititor believes the running commands on its session are
now cleaned up due to the successful response and cleans up the running
commands from its side. It then restarts them.

7. The commands do eventually complete on the backend and the target
starts to return aborted task statuses for them. The initiator will
either throw a invalid ITT error or might accidentally lookup a new
task if the ITT has been reallocated already.

Fix the bug by reverting the patch, and serialize the execution of
LUN_RESETs and Preempt and Aborts.

Also prevent us from waiting on LUN_RESETs in core_tmr_drain_tmr_list,
because it turns out the original patch fixed a bug that was not
mentioned. For LUN_RESET1 core_tmr_drain_tmr_list can see a second
LUN_RESET and wait on it. Then the second reset will run
core_tmr_drain_tmr_list and see the first reset and wait on it resulting in
a deadlock.

Fixes: 51ec502a3266 ("target: Delete tmr from list before processing")
Signed-off-by: Mike Christie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: Drop device-based RTPI

The code is not needed since target port-based RTPI allocation replaced it.

Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Roman Bolshakov <r.

scsi: target: core: Drop device-based RTPI

The code is not needed since target port-based RTPI allocation replaced it.

Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Roman Bolshakov <[email protected]>
Signed-off-by: Dmitry Bogdanov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

show more ...

scsi: target: core: Use RTPI from target port

Replace all references to RTPI from LUN field to se_portal_group field. It
introduces consistent reporting of RTPI for all LUNs and all target ports.

scsi: target: core: Use RTPI from target port

Replace all references to RTPI from LUN field to se_portal_group field. It
introduces consistent reporting of RTPI for all LUNs and all target ports.

Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Roman Bolshakov <[email protected]>
Signed-off-by: Dmitry Bogdanov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: Add emulate_rsoc attribute

Allow support for RSOC to be turned off via the emulate_rsoc attibute.
This is just for testing purposes.

Reviewed-by: Roman Bolshakov <r.bolshakov@ya

scsi: target: core: Add emulate_rsoc attribute

Allow support for RSOC to be turned off via the emulate_rsoc attibute.
This is just for testing purposes.

Reviewed-by: Roman Bolshakov <[email protected]>
Signed-off-by: Dmitry Bogdanov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: UA on all LUNs after reset

Allocate UNIT ATTENTION "BUS DEVICE RESET OCCURRED" on all LUNs on all
target ports of the device upon reception of TMF LUN RESET.

This change passes

scsi: target: core: UA on all LUNs after reset

Allocate UNIT ATTENTION "BUS DEVICE RESET OCCURRED" on all LUNs on all
target ports of the device upon reception of TMF LUN RESET.

This change passes libiscsi test SCSI.MultipathIO.Reset.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dmitry Bogdanov <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: De-RCU of se_lun and se_lun acl

se_lun and se_lun_acl are immutable pointers of struct se_dev_entry.
Remove RCU usage for access to those pointers.

Link: https://lore.kernel.org

scsi: target: core: De-RCU of se_lun and se_lun acl

se_lun and se_lun_acl are immutable pointers of struct se_dev_entry.
Remove RCU usage for access to those pointers.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Dmitry Bogdanov <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: Fix race during ACL removal

Under huge load there is a possibility of race condition in updating
se_dev_entry object in ACL removal procedure:

NIP [c0080000154093d0] transport_

scsi: target: core: Fix race during ACL removal

Under huge load there is a possibility of race condition in updating
se_dev_entry object in ACL removal procedure:

NIP [c0080000154093d0] transport_lookup_cmd_lun+0x1f8/0x3d0 [target_core_mod]
LR [c00800001542ab34] target_submit_cmd_map_sgls+0x11c/0x300 [target_core_mod]
Call Trace:
target_submit_cmd_map_sgls+0x11c/0x300 [target_core_mod]
target_submit_cmd+0x44/0x60 [target_core_mod]
tcm_qla2xxx_handle_cmd+0x88/0xe0 [tcm_qla2xxx]
qlt_do_work+0x2e4/0x3d0 [qla2xxx]
process_one_work+0x298/0x5c

Despite usage of RCU primitives with deve->se_lun pointer, it has not
become dereference-safe because deve->se_lun is updated and not
synchronized with a reader. That change might be in a release function
called by synchronize_rcu(). But, in fact, there is no point in setting
that pointer to NULL for deleting deve. All access to deve->se_lun is
already under rcu_read_lock. And either deve->se_lun is always valid or
deve is not valid itself and will not be found in the list_for_*. The same
applicable for deve->se_lun_acl too. So a better solution is to remove
that NULLing.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Dmitry Bogdanov <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: Add callout to configure UNMAP settings

Add a callout to configure a backend's UNMAP settings. This will be used to
allow userspace to configure UNMAP after the initial device setup, s

scsi: target: Add callout to configure UNMAP settings

Add a callout to configure a backend's UNMAP settings. This will be used to
allow userspace to configure UNMAP after the initial device setup, similar
to how we can set up the other attributes post device configuration.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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block: add a bdev_discard_granularity helper

Abstract away implementation details from file systems by providing a
block_device based helper to retrieve the discard granularity.

Signed-off-by: Chri

block: add a bdev_discard_granularity helper

Abstract away implementation details from file systems by providing a
block_device based helper to retrieve the discard granularity.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Acked-by: Christoph Böhmwalder <[email protected]> [drbd]
Acked-by: Ryusuke Konishi <[email protected]>
Acked-by: David Sterba <[email protected]> [btrfs]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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block: remove QUEUE_FLAG_DISCARD

Just use a non-zero max_discard_sectors as an indicator for discard
support, similar to what is done for write zeroes.

The only places where needs special attention

block: remove QUEUE_FLAG_DISCARD

Just use a non-zero max_discard_sectors as an indicator for discard
support, similar to what is done for write zeroes.

The only places where needs special attention is the RAID5 driver,
which must clear discard support for security reasons by default,
even if the default stacking rules would allow for it.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Acked-by: Christoph Böhmwalder <[email protected]> [drbd]
Acked-by: Jan Höppner <[email protected]> [s390]
Acked-by: Coly Li <[email protected]> [bcache]
Acked-by: David Sterba <[email protected]> [btrfs]
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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block: add a bdev_max_discard_sectors helper

Add a helper to query the number of sectors support per each discard bio
based on the block device and use this helper to stop various places from
poking

block: add a bdev_max_discard_sectors helper

Add a helper to query the number of sectors support per each discard bio
based on the block device and use this helper to stop various places from
poking into the request_queue to see if discard is supported and if so how
much. This mirrors what is done e.g. for write zeroes as well.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Acked-by: Christoph Böhmwalder <[email protected]> [drbd]
Acked-by: Coly Li <[email protected]> [bcache]
Acked-by: David Sterba <[email protected]> [btrfs]
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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target: fix discard alignment on partitions

Use the proper bdev_discard_alignment helper that accounts for partition
offsets.

Fixes: c66ac9db8d4a ("[SCSI] target: Add LIO target core v4.0.0-rc6")
S

target: fix discard alignment on partitions

Use the proper bdev_discard_alignment helper that accounts for partition
offsets.

Fixes: c66ac9db8d4a ("[SCSI] target: Add LIO target core v4.0.0-rc6")
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

target: pass a block_device to target_configure_unmap_from_queue

The SCSI target drivers is a consumer of the block layer and shoul
d generally work on struct block_device.

Signed-off-by: Christoph

target: pass a block_device to target_configure_unmap_from_queue

The SCSI target drivers is a consumer of the block layer and shoul
d generally work on struct block_device.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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target: remove an incorrect unmap zeroes data deduction

For block devices, the SCSI target drivers implements UNMAP as calls to
blkdev_issue_discard, which does not guarantee zeroing just because
Wr

target: remove an incorrect unmap zeroes data deduction

For block devices, the SCSI target drivers implements UNMAP as calls to
blkdev_issue_discard, which does not guarantee zeroing just because
Write Zeroes is supported.

Note that this does not affect the file backed path which uses
fallocate to punch holes.

Fixes: 2237498f0b5c ("target/iblock: Convert WRITE_SAME to blkdev_issue_zeroout")
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

scsi: target: Fix ordered tag handling

This patch fixes the following bugs:

1. If there are multiple ordered cmds queued and multiple simple cmds
completing, target_restart_delayed_cmds() could

scsi: target: Fix ordered tag handling

This patch fixes the following bugs:

1. If there are multiple ordered cmds queued and multiple simple cmds
completing, target_restart_delayed_cmds() could be called on different
CPUs and each instance could start a ordered cmd. They could then run in
different orders than they were queued.

2. target_restart_delayed_cmds() and target_handle_task_attr() can race
where:

1. target_handle_task_attr() has passed the simple_cmds == 0 check.

2. transport_complete_task_attr() then decrements simple_cmds to 0.

3. transport_complete_task_attr() runs target_restart_delayed_cmds() and
it does not see any cmds on the delayed_cmd_list.

4. target_handle_task_attr() adds the cmd to the delayed_cmd_list.

The cmd will then end up timing out.

3. If we are sent > 1 ordered cmds and simple_cmds == 0, we can execute
them out of order, because target_handle_task_attr() will hit that
simple_cmds check first and return false for all ordered cmds sent.

4. We run target_restart_delayed_cmds() after every cmd completion, so if
there is more than 1 simple cmd running, we start executing ordered cmds
after that first cmd instead of waiting for all of them to complete.

5. Ordered cmds are not supposed to start until HEAD OF QUEUE and all older
cmds have completed, and not just simple.

6. It's not a bug but it doesn't make sense to take the delayed_cmd_lock
for every cmd completion when ordered cmds are almost never used. Just
replacing that lock with an atomic increases IOPs by up to 10% when
completions are spread over multiple CPUs and there are multiple
sessions/ mqs/thread accessing the same device.

This patch moves the queued delayed handling to a per device work to
serialze the cmd executions for each device and adds a new counter to track
HEAD_OF_QUEUE and SIMPLE cmds. We can then check the new counter to
determine when to run the work on the completion path.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: core: Add configurable IEEE Company ID attribute

Implement an attribute which provides a way to set a company specific WWN
in configfs via:

target/core/$backstore/$name/wwn/company_

scsi: target: core: Add configurable IEEE Company ID attribute

Implement an attribute which provides a way to set a company specific WWN
in configfs via:

target/core/$backstore/$name/wwn/company_id

The Open Fabrics Alliance ID 001405h remains the default.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sergey Samoylenko <[email protected]>
Signed-off-by: Roman Bolshakov <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

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scsi: target: Make the virtual LUN 0 device

Create the device for the virtual LUN 0 using the DUMMY flag. This change
makes it possible to remove some special-casing in the INQUIRY code.

Link: http

scsi: target: Make the virtual LUN 0 device

Create the device for the virtual LUN 0 using the DUMMY flag. This change
makes it possible to remove some special-casing in the INQUIRY code.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Roman Bolshakov <[email protected]>
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Konstantin Shelekhin <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

show more ...