linux-stable.git/include/target/target_core_base.h, branch v5.13.2

scsi: target: core: Make completion affinity configurable

2021-03-04T22:37:03+00:00

It may not always be best to complete the IO on same CPU as it was
submitted on. This commit allows userspace to configure it.

This has been useful for vhost-scsi where we have a single thread for
submissions and completions. If we force the completion on the submission
CPU we may be adding conflicts with what the user has setup in the lower
levels with settings like the block layer rq_affinity or the driver's IRQ
or softirq (the network's rps_cpus value) settings.

We may also want to set it up where the vhost thread runs on CPU N and does
its submissions/completions there, and then have LIO do its completion
booking on CPU M, but can't configure the lower levels due to issues like
using dm-multipath with lots of paths (the path selector can throw commands
all over the system because it's only taking into account latency/throughput
at its level).

The new setting is in:

    /sys/kernel/config/target/$fabric/$target/param/cmd_completion_affinity

Writing:

    -1 -> Gives the current default behavior of completing on the
          submission CPU.

    -2 -> Completes the cmd on the CPU the lower layers sent it to us from.

   > 0 -> Completes on the CPU userspace has specified.

Link: https://lore.kernel.org/r/20210227170006.5077-26-michael.christie@oracle.com
Reviewed-by: Himanshu Madhani 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: target: core: Fix backend plugging

2021-03-04T22:37:02+00:00

target_core_iblock is plugging and unplugging on every command and this is
causing perf issues for drivers that prefer batched cmds. With recent
patches we can now take multiple cmds from a fabric driver queue and then
pass them down the backend drivers in a batch. This patch adds this support
by adding 2 callouts to the backend for plugging and unplugging the
device. Subsequent commits will add support for iblock and tcmu device
plugging.

Link: https://lore.kernel.org/r/20210227170006.5077-22-michael.christie@oracle.com
Reviewed-by: Bodo Stroesser 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: target: core: Cleanup cmd flag bits

2021-03-04T22:37:02+00:00

We have a couple holes in the cmd flags definitions. This cleans up the
definitions to fix that and make it easier to read.

Link: https://lore.kernel.org/r/20210227170006.5077-21-michael.christie@oracle.com
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Himanshu Madhani 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: target: core: Add workqueue based cmd submission

2021-03-04T22:37:02+00:00

loop and vhost/scsi do their target cmd submission from driver
workqueues. This allows them to avoid an issue where the backend may block
waiting for resources like tags/requests, mem/locks, etc and that ends up
blocking their entire submission path and for the case of vhost-scsi both
the submission and completion path.

This patch adds a helper drivers can use to submit from a LIO workqueue.
This code will then be extended in the next patches to fix the plugging of
backend devices.

We are only converting vhost/loop initially, but the workqueue based
submission will work for other drivers and have similar benefits where the
main target loops will not end up blocking one some backend resource.

Link: https://lore.kernel.org/r/20210227170006.5077-17-michael.christie@oracle.com
Tested-by: Laurence Oberman 
Reviewed-by: Bodo Stroesser 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: target: core: Change ASCQ for residual write

2021-01-27T04:12:18+00:00

According to FCP-4 (9.4.2):

  If the command requested that data beyond the length specified by the
  FCP_DL field be transferred, then the device server shall set the
  FCP_RESID_OVER bit (see 9.5.8) to one in the FCP_RSP IU and:

  a) process the command normally except that data beyond the FCP_DL count
  shall not be requested or transferred;

  b) transfer no data and return CHECK CONDITION status with the sense key
  set to ILLEGAL REQUEST and the additional sense code set to INVALID FIELD
  IN COMMAND INFORMATION UNIT; or

  c) may transfer data and return CHECK CONDITION status with the sense key
  set to ABORTED COMMAND and the additional sense code set to INVALID FIELD
  IN COMMAND INFORMATION UNIT.

TCM follows b) and transfers no data for residual writes but returns
INVALID FIELD IN CDB instead of INVALID FIELD IN COMMAND INFORMATION UNIT.

Change the ASCQ to INVALID FIELD IN COMMAND INFORMATION UNIT to meet the
standard.

Link: https://lore.kernel.org/r/20201203082035.54566-4-a.kovaleva@yadro.com
Signed-off-by: Anastasia Kovaleva 
Signed-off-by: Roman Bolshakov 
Signed-off-by: Martin K. Petersen

scsi: target: Make state_list per CPU

2020-11-05T03:39:38+00:00

Do a state_list/execute_task_lock per CPU, so we can do submissions from
different CPUs without contention with each other.

Note: tcm_fc was passing TARGET_SCF_USE_CPUID, but never set cpuid.  The
assumption is that it wanted to set the cpuid to the CPU it was submitting
from so it will get this behavior with this patch.

[mkp: s/printk/pr_err/ + resolve COMPARE AND WRITE patch conflict]

Link: https://lore.kernel.org/r/1604257174-4524-8-git-send-email-michael.christie@oracle.com
Reviewed-by: Himanshu Madhani 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: target: Drop sess_cmd_lock from I/O path

2020-11-05T03:39:37+00:00

Drop the sess_cmd_lock by:

 - Removing the sess_cmd_list use from LIO core, because it's been
   moved to qla2xxx.

 - Removing sess_tearing_down check in the I/O path. Instead of using that
   bit and the sess_cmd_lock, we rely on the cmd_count percpu ref. To do
   this we switch to percpu_ref_kill_and_confirm/percpu_ref_tryget_live.

Link: https://lore.kernel.org/r/1604257174-4524-7-git-send-email-michael.christie@oracle.com
Reviewed-by: Himanshu Madhani 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: target: Remove TARGET_SCF_LOOKUP_LUN_FROM_TAG

2020-11-05T03:39:37+00:00

TARGET_SCF_LOOKUP_LUN_FROM_TAG is no longer used so remove it.

Link: https://lore.kernel.org/r/1604257174-4524-5-git-send-email-michael.christie@oracle.com
Reviewed-by: Himanshu Madhani 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: target: Rename cmd.bad_sector to cmd.sense_info

2020-11-05T03:02:19+00:00

cmd.bad_sector currently gets packed into the sense INFORMATION field for
TCM_LOGICAL_BLOCK_{GUARD,APP_TAG,REF_TAG}_CHECK_FAILED errors, which carry
an .add_sector_info flag in the sense_detail_table to ensure this.

In preparation for propagating a byte offset on COMPARE AND WRITE
TCM_MISCOMPARE_VERIFY error, rename cmd.bad_sector to cmd.sense_info and
sense_detail.add_sector_info to sense_detail.add_sense_info so that it
better reflects the sense INFORMATION field destination.

[ddiss: update previously overlooked ib_isert]

Link: https://lore.kernel.org/r/20201031233211.5207-3-ddiss@suse.de
Reviewed-by: Mike Christie 
Signed-off-by: David Disseldorp 
Signed-off-by: Martin K. Petersen

scsi: target: Add tmr_notify backend function

2020-07-29T02:25:26+00:00

Target core is modified to call an optional backend callback function if a
TMR is received or commands are aborted implicitly after a PR command was
received.  The backend function takes as parameters the se_dev, the type of
the TMR, and the list of aborted commands.  If no commands were aborted, an
empty list is supplied.

Link: https://lore.kernel.org/r/20200726153510.13077-3-bstroesser@ts.fujitsu.com
Reviewed-by: Mike Christie 
Signed-off-by: Bodo Stroesser 
Signed-off-by: Martin K. Petersen