kernel/linux.git/include/target/target_core_base.h, branch v6.1.168

scsi: target: Fix multiple LUN_RESET handling

2023-05-11T14:03:19+00:00

[ Upstream commit 673db054d7a2b5a470d7a25baf65956d005ad729 ] 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 Signed-off-by: Sasha Levin

scsi: target: Move sess cmd counter to new struct

2023-05-11T14:03:19+00:00

[ Upstream commit becd9be6069e7b183c084f460f0eb363e43cc487 ] 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 Stable-dep-of: 395cee83d02d ("scsi: target: iscsit: Stop/wait on cmds during conn close") Signed-off-by: Sasha Levin

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

2022-08-01T23:36:02+00:00

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/20220727214125.19647-3-d.bogdanov@yadro.com Reviewed-by: Mike Christie Signed-off-by: Dmitry Bogdanov Signed-off-by: Martin K. Petersen

scsi: target: Replace lun_tg_pt_gp_lock with rcu in I/O path

2021-10-19T02:38:36+00:00

We are only holding the lun_tg_pt_gp_lock in target_alua_state_check() to make sure tg_pt_gp is not freed from under us while we copy the state, delay, ID values. We can instead use RCU here to access the tg_pt_gp. With this patch IOPs can increase up to 10% for jobs like: fio --filename=/dev/sdX --direct=1 --rw=randrw --bs=4k \ --ioengine=libaio --iodepth=64 --numjobs=N when there are multiple sessions (running that fio command to each /dev/sdX or using multipath and there are over 8 paths), or more than 8 queues for the loop or vhost with multiple threads case and numjobs > 8. Link: https://lore.kernel.org/r/20210930020422.92578-5-michael.christie@oracle.com Signed-off-by: Mike Christie 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: Add common tpg/enable attribute

2021-10-05T03:27:38+00:00

Many fabric modules provide their own implementation of enable attribute in tpg. Provide a way to remove code duplication in the fabric modules and automatically add "enable" attribute if a fabric module has an implementation of fabric_enable_tpg(). Link: https://lore.kernel.org/r/20210910084133.17956-2-d.bogdanov@yadro.com Reviewed-by: Roman Bolshakov Reviewed-by: Mike Christie Signed-off-by: Dmitry Bogdanov Signed-off-by: Martin K. Petersen

scsi: target: Allows backend drivers to fail with specific sense codes

2021-08-18T02:28:40+00:00

Currently, backend drivers can fail I/O with SAM_STAT_CHECK_CONDITION which gets us TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE. Add a new helper that allows backend drivers to fail with specific sense codes. This is based on a patch from Mike Christie . Cc: Mike Christie Link: https://lore.kernel.org/r/20210803145410.80147-2-s.samoylenko@yadro.com Reviewed-by: David Disseldorp Signed-off-by: Sergey Samoylenko Signed-off-by: Martin K. Petersen

scsi: target: core: Drop unnecessary se_cmd ASC/ASCQ members

2021-08-03T11:27:43+00:00

These members are only used for ALUA sense detail propagation, which can just as easily be done via sense_reason_t. Link: https://lore.kernel.org/r/20210728115353.2396-4-ddiss@suse.de Reviewed-by: Mike Christie Signed-off-by: David Disseldorp Signed-off-by: Martin K. Petersen

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

2021-05-15T18:14:28+00:00

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/20210420185920.42431-3-s.samoylenko@yadro.com Signed-off-by: Sergey Samoylenko Signed-off-by: Roman Bolshakov 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