kernel/linux.git/drivers/target/target_core_internal.h, branch v6.19.11

scsi: target: Move LUN stats to per-CPU

2025-11-03T03:06:12+00:00

The atomic use in the main I/O path is causing perf issues when using higher performance backend devices and multiple queues (more than 10 when using vhost-scsi) like with this fio workload: [global] bs=4K iodepth=128 direct=1 ioengine=libaio group_reporting time_based runtime=120 name=standard-iops rw=randread numjobs=16 cpus_allowed=0-15 To fix this issue, move the LUN stats to per CPU. Note: I forgot to include this patch with the delayed/ordered per CPU tracking and per device/device entry per CPU stats. With this patch you get the full 33% improvements when using fast backends, multiple queues and multiple IO submiters. Signed-off-by: Mike Christie Reviewed-by: Dmitry Bogdanov Link: https://patch.msgid.link/20250917221338.14813-4-michael.christie@oracle.com Signed-off-by: Martin K. Petersen

scsi: target: core: Generate correct identifiers for PR OUT transport IDs

2025-07-25T01:57:00+00:00

Fix target_parse_pr_out_transport_id() to return a string representing the transport ID in a human-readable format (e.g., naa.xxxxxxxx...) for various SCSI protocol types (SAS, FCP, SRP, SBP). Previously, the function returned a pointer to the raw binary buffer, which was incorrectly compared against human-readable strings, causing comparisons to fail. Now, the function writes a properly formatted string into a buffer provided by the caller. The output format depends on the transport protocol: * SAS: 64-bit identifier, "naa." prefix. * FCP: 64-bit identifier, colon separated values. * SBP: 64-bit identifier, no prefix. * SRP: 128-bit identifier, "0x" prefix. * iSCSI: IQN string. Signed-off-by: Maurizio Lombardi Link: https://lore.kernel.org/r/20250714133738.11054-1-mlombard@redhat.com Reviewed-by: Dmitry Bogdanov 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: Move cmd counter allocation

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

iSCSI needs to allocate its cmd counter per connection for MCS support where we need to stop and wait on commands running on a connection instead of per session. This moves the cmd counter allocation to target_setup_session() which is used by drivers that need the stop+wait behavior per session. xcopy doesn't need stop+wait at all, so we will be OK moving the cmd counter allocation outside of transport_init_session(). Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/20230319015620.96006-3-michael.christie@oracle.com 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

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

2022-10-01T09:06:53+00:00

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/20220913163602.20597-1-d.bogdanov@yadro.com Signed-off-by: Dmitry Bogdanov Signed-off-by: Martin K. Petersen

scsi: target: Remove unused se_tmr_req_cache declaration

2022-09-16T01:46:46+00:00

se_tmr_req_cache has been removed since commit c8e31f26feeb ("target: Add SCF_SCSI_TMR_CDB usage and drop se_tmr_req_cache"). Remove extern. Link: https://lore.kernel.org/r/20220913023722.547249-3-cuigaosheng1@huawei.com Signed-off-by: Gaosheng Cui Signed-off-by: Martin K. Petersen

scsi: target: Fix ordered tag handling

2021-10-19T02:38:35+00:00

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/20210930020422.92578-3-michael.christie@oracle.com Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen

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