kernel/linux.git/include/target/target_core_backend.h, branch v6.6.131

scsi: target: Allow backends to hook into PR handling

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

For the cases where you want to export a device to a VM via a single I_T nexus and want to passthrough the PR handling to the physical/real device you have to use pscsi or tcmu. Both are good for specific uses however for the case where you want good performance, and are not using SCSI devices directly (using DM/MD RAID or multipath devices) then we are out of luck. The following patches allow iblock to mimimally hook into the LIO PR code and then pass the PR handling to the physical device. Note that like with the tcmu an pscsi cases it's only supported when you export the device via one I_T nexus. This patch adds the initial LIO callouts. The next patch will modify iblock. Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/20230407200551.12660-16-michael.christie@oracle.com Reviewed-by: Christoph Hellwig Signed-off-by: Martin K. Petersen

scsi: target: Rename sbc_ops to exec_cmd_ops

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

The next patches allow us to call the block layer's pr_ops from the backends. This will require allowing the backends to hook into the cmd processing for SPC commands, so this renames sbc_ops to a more generic exec_cmd_ops. Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/20230407200551.12660-15-michael.christie@oracle.com Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

scsi: target: Add callout to configure UNMAP settings

2022-07-07T20:53:52+00:00

Add a callout to configure a backend's UNMAP settings. This will be used to allow userspace to configure UNMAP after the initial device setup, similar to how we can set up the other attributes post device configuration. Link: https://lore.kernel.org/r/20220628200230.15052-3-michael.christie@oracle.com Reviewed-by: Christoph Hellwig Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen

target: pass a block_device to target_configure_unmap_from_queue

2022-04-18T01:49:58+00:00

The SCSI target drivers is a consumer of the block layer and shoul d generally work on struct block_device. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20220415045258.199825-3-hch@lst.de Signed-off-by: Jens Axboe

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: 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: Add cmd length set before cmd complete

2021-02-23T03:21:29+00:00

TCM doesn't properly handle underflow case for service actions. One way to prevent it is to always complete command with target_complete_cmd_with_length(), however it requires access to data_sg, which is not always available. This change introduces target_set_cmd_data_length() function which allows to set command data length before completing it. Link: https://lore.kernel.org/r/20210209072202.41154-2-a.miloserdov@yadro.com Reviewed-by: Roman Bolshakov Reviewed-by: Bodo Stroesser Signed-off-by: Aleksandr Miloserdov 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

scsi: target: tcmu: Make pgr_support and alua_support attributes writable

2020-05-08T02:39:22+00:00

Currently in tcmu reservation commands are handled by core's pr implementation (default) or completely rejected (emulate_pr set to 0). We additionally want to be able to do full reservation handling in userspace. Therefore we need a way to set TRANSPORT_FLAG_PASSTHROUGH_PGR. The inverted flag is displayed by attribute pgr_support. Since we moved the flag from transport/backend to se_device in the previous commit, we now can make it changeable per device by allowing to write the attribute. The new field transport_flags_changeable in transport/backend is used to reject writing if not allowed for a backend. Regarding ALUA we also want to be able to passthrough commands to userspace in tcmu. Therefore we need TRANSPORT_FLAG_PASSTHROUGH_ALUA to be changeable, because by setting it we can switch off all ALUA checks in core. So we also set TRANSPORT_FLAG_PASSTHROUGH_ALUA in tcmu's transport_flags_changeable. Of course, ALUA and reservation handling in userspace will work only, if session/nexus information is sent to userspace along with every command. This will be object of a patch series announced by Mike Christie. Link: https://lore.kernel.org/r/20200427150823.15350-5-bstroesser@ts.fujitsu.com Reviewed-by: Mike Christie Signed-off-by: Bodo Stroesser Signed-off-by: Martin K. Petersen

scsi: target: Make transport_flags per device

2020-05-08T02:39:21+00:00

pgr_support and alua_support device attributes show the inverted value of the transport_flags: * TRANSPORT_FLAG_PASSTHROUGH_PGR * TRANSPORT_FLAG_PASSTHROUGH_ALUA These attributes are per device, while the flags are per backend. Rename the transport_flags in backend/transport to transport_flags_default and use this value to initialize the new transport_flags field in the se_device structure. Now data and attribute both are per se_device. Link: https://lore.kernel.org/r/20200427150823.15350-4-bstroesser@ts.fujitsu.com Reviewed-by: Mike Christie Signed-off-by: Bodo Stroesser Signed-off-by: Martin K. Petersen