From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> Hi Hannes, HCH, & Sagi, Here is an initial pass at the conversion of se_node_acl->device_list[] to use RCU protected pointers for se_lun fast-path lookup code. The big advantage with RCU is that transport_lookup_cmd_lun() can now run completely lock-less using existing per-cpu se_lun->lun_ref logic. Currently the new se_node_acl->lun_entry_hlist is still using an array of pointers allocated at se_node_acl creation time. The next step on my end is to convert the entries to mempool allocation + rcu_head -> call_rcu() asynchronous release. Beyond that, RCU hlist support for both NodeACL MappedLUN and TPG LUN tables is the final goal. Some of the more interesting conversions so far are in target_core_pr.c code for PROUT operations that lookup remote I_T LUNs and take configfs dependencies. This includes a new se_dev_entry->pr_ref to handle the REGISTER w/ I_PORT descriptors + REGISTER_AND_MOVE special cases. The series is broken up for review, and also includes a struct mutex conversion of existing se_node_acl and se_portal_group LUN locks to simplify a number of existing codepaths. There are still a number of outstanding FIXMEs to address, and at this point the series is stable enough to function with CONFIG_PROVE_RCU=y. However, it still needs alot more testing with active I/O shutdown and complex PR use cases. Along with other cleanups, the target_* prefix rename discussed at LSF is also included at the series end. Please have a look. --nab Nicholas Bellinger (22): target: Convert transport_lookup_*_lun to RCU reader target: Convert enable/disable ->device_list to RCU updater target/device: Convert se_node_acl->device_list access to RCU reader target/configfs: Convert mappedlun link/unlink to RCU reader target/configfs: Convert SCSI MIB attrs to RCU reader target/spc: Convert REPORT_LUN + MODE_SENSE to RCU reader target/pscsi: Convert MODE_SENSE special case to RCU reader target/pr: Convert se_dev_entry to percpu-refcount for RCU target/pr: Convert registration check to RCU pointer target/pr: Change alloc_registration to avoid pr_reg_tg_pt_lun target: Convert UNIT_ATTENTION logic to RCU reader target: Convert se_tpg->tpg_lun_lock to ->tpg_lun_mutex target: Convert se_tpg->acl_node_lock to ->acl_node_mutex target: Convert se_node_acl->lun_entry_lock to ->lun_entry_mutex target: Convert core_tpg_deregister to use list splice target: Drop se_lun->lun_acl_list target: Drop core_tpg_clear_object_luns target: Rename TPG initiator_node_acl to target_* prefix target: Rename TPG register/deregister to target_* prefix target: Rename LUN lookup/add/remove to target_* prefix target: Rename se_node_acl->lun_entry_hlist to target_* prefix target: Rename se_port/se_device export to target_* prefix drivers/infiniband/ulp/srpt/ib_srpt.c | 15 +- drivers/scsi/qla2xxx/tcm_qla2xxx.c | 22 +- drivers/target/iscsi/iscsi_target.c | 10 +- drivers/target/iscsi/iscsi_target_configfs.c | 17 +- drivers/target/iscsi/iscsi_target_nego.c | 4 +- drivers/target/iscsi/iscsi_target_tpg.c | 12 +- drivers/target/loopback/tcm_loop.c | 14 +- drivers/target/sbp/sbp_target.c | 34 ++- drivers/target/target_core_configfs.c | 6 +- drivers/target/target_core_device.c | 295 ++++++++++++++------------- drivers/target/target_core_fabric_configfs.c | 29 +-- drivers/target/target_core_internal.h | 24 +-- drivers/target/target_core_pr.c | 213 +++++++++++-------- drivers/target/target_core_pscsi.c | 14 +- drivers/target/target_core_spc.c | 28 ++- drivers/target/target_core_stat.c | 168 +++++++-------- drivers/target/target_core_tpg.c | 244 ++++++++++------------ drivers/target/target_core_transport.c | 24 +-- drivers/target/target_core_ua.c | 35 ++-- drivers/target/tcm_fc/tfc_conf.c | 16 +- drivers/usb/gadget/legacy/tcm_usb_gadget.c | 22 +- drivers/vhost/scsi.c | 18 +- drivers/xen/xen-scsiback.c | 8 +- include/target/target_core_base.h | 23 +-- include/target/target_core_fabric.h | 21 +- 25 files changed, 678 insertions(+), 638 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
