kernel.git/drivers/target/target_core_internal.h, branch linux-6.3.y

scsi: target: Move cmd counter allocation

2023-05-11T14:17:13Z

[ Upstream commit 4edba7e4a8f39112398d3cda94128a8e13a7d527 ] 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 Stable-dep-of: 395cee83d02d ("scsi: target: iscsit: Stop/wait on cmds during conn close") Signed-off-by: Sasha Levin

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

2022-10-01T09:06:53Z

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

2022-09-16T01:46:46Z

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

2021-10-19T02:38:35Z

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

2021-03-04T22:37:03Z

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: Add workqueue based cmd submission

2021-03-04T22:37:02Z

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: Fix xcopy sess release leak

2020-07-08T04:14:34Z

transport_init_session can allocate memory via percpu_ref_init, and target_xcopy_release_pt never frees it. This adds a transport_uninit_session function to handle cleanup of resources allocated in the init function. Link: https://lore.kernel.org/r/1593654203-12442-3-git-send-email-michael.christie@oracle.com Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen

scsi: target/core: Make ABORT and LUN RESET handling synchronous

2018-12-08T02:22:55Z

Instead of invoking target driver callback functions from the context that handles an abort or LUN RESET task management function, only set the abort flag from that context and perform the actual abort handling from the context of the regular command processing flow. This approach has the advantage that the task management code becomes much easier to read and to verify since the number of potential race conditions against the command processing flow is strongly reduced. This patch has been tested by running the following two shell commands concurrently for about ten minutes for both the iSCSI and the SRP target drivers ($dev is an initiator device node connected with storage provided by the target driver under test): * fio with data verification enabled on a filesystem mounted on top of $dev. * while true; do sg_reset -d $dev; echo -n .; sleep .1; done Cc: Nicholas Bellinger Cc: Mike Christie Cc: Christoph Hellwig Cc: David Disseldorp Cc: Hannes Reinecke Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen

scsi: target: Fold core_tmr_handle_tas_abort() into transport_cmd_finish_abort()

2018-07-02T20:44:31Z

For the two calls to transport_cmd_finish_abort() outside core_tmr_handle_tas_abort() it is guaranteed that CMD_T_TAS is not set. Use this property to fold core_tmr_handle_tas_abort() into transport_cmd_finish_abort(). This patch does not change any functionality. Signed-off-by: Bart Van Assche Reviewed-by: Mike Christie Cc: Hannes Reinecke Cc: Christoph Hellwig Signed-off-by: Martin K. Petersen

scsi: target: prefer dbroot of /etc/target over /var/target

2018-04-19T04:47:02Z

The target database root directory, dbroot, has defaulted to /var/target for a while, but its main client, targetcli-fb, has been moving it to /etc/target for quite some time. With the plethora of target drivers now appearing, it has become more difficult to initialize this attribute before use by any child drivers. If the directory /etc/target exists, use that as the DB root. Otherwise, fall back to using /var/target. The ability to override this dbroot attribute still exists via sysfs. Signed-off-by: Lee Duncan Reviewed-by: Christoph Hellwig Signed-off-by: Martin K. Petersen