kernel/linux.git/include/target/target_core_base.h, branch v6.12.80

scsi: target: Allow userspace to request direct submissions

2023-10-13T19:53:58+00:00

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 Link: https://lore.kernel.org/r/20230928020907.5730-6-michael.christie@oracle.com Signed-off-by: Martin K. Petersen

scsi: target: Have drivers report if they support direct submissions

2023-10-13T19:53:57+00:00

In some cases, like with multiple LUN targets or where the target has to respond to transport level requests from the receiving context it can be better to defer cmd submission to a helper thread. If the backend driver blocks on something like request/tag allocation it can block the entire target submission path and other LUs and transport IO on that session. In other cases like single LUN targets with storage that can support all the commands that the target can queue, then it's best to submit the cmd to the backend from the target's cmd receiving context. Subsequent commits will allow the user to config what they prefer, but drivers like loop can't directly submit because they can be called from a context that can't sleep. And, drivers like vhost-scsi can support direct submission, but need to keep their default behavior of deferring execution to avoid possible regressions where the backend can block. Make the drivers tell LIO core if they support direct submissions and their current default, so we can prevent users from misconfiguring the system and initialize devices correctly. Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/20230928020907.5730-2-michael.christie@oracle.com Signed-off-by: Martin K. Petersen

Merge patch series "Use block pr_ops in LIO"

2023-05-22T20:35:02+00:00

Mike Christie says: The patches in this thread allow us to use the block pr_ops with LIO's target_core_iblock module to support cluster applications in VMs. They were built over Linus's tree. They also apply over linux-next and Martin's tree and Jens's trees. Currently, to use windows clustering or linux clustering (pacemaker + cluster labs scsi fence agents) in VMs with LIO and vhost-scsi, you have to use tcmu or pscsi or use a cluster aware FS/framework for the LIO pr file. Setting up a cluster FS/framework is pain and waste when your real backend device is already a distributed device, and pscsi and tcmu are nice for specific use cases, but iblock gives you the best performance and allows you to use stacked devices like dm-multipath. So these patches allow iblock to work like pscsi/tcmu where they can pass a PR command to the backend module. And then iblock will use the pr_ops to pass the PR command to the real devices similar to what we do for unmap today. The patches are separated in the following groups: Patch 1 - 2: - Add block layer callouts for reading reservations and rename reservation error code. Patch 3 - 5: - SCSI support for new callouts. Patch 6: - DM support for new callouts. Patch 7 - 13: - NVMe support for new callouts. Patch 14 - 18: - LIO support for new callouts. This patchset has been tested with the libiscsi PGR ops and with window's failover cluster verification test. Note that for scsi backend devices we need this patchset: https://lore.kernel.org/linux-scsi/20230123221046.125483-1-michael.christie@oracle.com/T/#m4834a643ffb5bac2529d65d40906d3cfbdd9b1b7 to handle UAs. To reduce the size of this patchset that's being done separately to make reviewing easier. And to make merging easier this patchset and the one above do not have any conflicts so can be merged in different trees. Link: https://lore.kernel.org/r/20230407200551.12660-1-michael.christie@oracle.com Signed-off-by: Martin K. Petersen

scsi: target: Pass struct target_opcode_descriptor to enabled

2023-04-12T01:55:36+00:00

The iblock pr_ops support does not support commands that require port or I_T Nexus info. This adds a struct target_opcode_descriptor as an argument to the enabled callout so we can still have the common tcm_is_pr_enabled and tcm_is_scsi2_reservations_enabled functions and also determine if the command is supported based on the command and service action and device settings. Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/20230407200551.12660-17-michael.christie@oracle.com Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

Merge patch series "target: TMF and recovery fixes"

2023-03-24T21:39:15+00:00

Mike Christie says: The following patches apply over Martin's 6.4 branches and Linus's tree. They fix a couple regressions in iscsit that occur when there are TMRs executing and a connection is closed. It also includes Dimitry's fixes in related code paths for cmd cleanup when ERL2 is used and the write pending hang during conn cleanup. This version of the patchset brings it back to just regressions and fixes for bugs we have a lot of users hitting. I'm going to fix isert and get it hooked into iscsit properly in a second patchset, because this one was getting so large. I've also moved my cleanup type of patches for a 3rd patchset. Link: https://lore.kernel.org/r/20230319015620.96006-1-michael.christie@oracle.com Signed-off-by: Martin K. Petersen

scsi: target: Fix multiple LUN_RESET handling

2023-03-24T21:32:23+00:00

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 Link: https://lore.kernel.org/r/20230319015620.96006-8-michael.christie@oracle.com Signed-off-by: Martin K. Petersen

scsi: target: Move sess cmd counter to new struct

2023-03-24T21:32:22+00:00

iSCSI needs to wait on outstanding commands like how SRP and the FC/FCoE drivers do. It can't use target_stop_session() because for MCS support we can't stop the entire session during recovery because if other connections are OK then we want to be able to continue to execute I/O on them. Move the per session cmd counters to a new struct so iSCSI can allocate them per connection. The xcopy code can also just not allocate in the future since it doesn't need to track commands. Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/20230319015620.96006-2-michael.christie@oracle.com Reviewed-by: Maurizio Lombardi Signed-off-by: Martin K. Petersen

scsi: target: core: Add RTPI attribute for target port

2023-03-10T02:29:23+00:00

RELATIVE TARGET PORT IDENTIFIER can be read and configured via configfs: $ echo 0x10 > $TARGET/tpgt_N/rtpi RTPI can be changed only on disabled target ports. Co-developed-by: Roman Bolshakov Signed-off-by: Roman Bolshakov Signed-off-by: Dmitry Bogdanov Link: https://lore.kernel.org/r/20230301084512.21956-5-d.bogdanov@yadro.com Reviewed-by: Mike Christie Signed-off-by: Martin K. Petersen

scsi: target: core: Drop device-based RTPI

2023-03-10T02:29:23+00:00

The code is not needed since target port-based RTPI allocation replaced it. Reviewed-by: Christoph Hellwig Signed-off-by: Roman Bolshakov Signed-off-by: Dmitry Bogdanov Link: https://lore.kernel.org/r/20230301084512.21956-4-d.bogdanov@yadro.com Reviewed-by: Mike Christie Signed-off-by: Martin K. Petersen

scsi: target: core: Add RTPI field to target port

2023-03-10T02:29:23+00:00

SAM-5 4.6.5.2 (Relative Port Identifier attribute) defines the attribute as unique across SCSI target ports. The change introduces RTPI attribute to se_portal group. The value is unique across all enabled SCSI target ports. It also limits number of SCSI target ports to 65535. Signed-off-by: Dmitry Bogdanov Link: https://lore.kernel.org/r/20230301084512.21956-2-d.bogdanov@yadro.com Reviewed-by: Mike Christie Signed-off-by: Martin K. Petersen