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path: root/drivers/target/target_core_rd.c
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2014-04-07target/rd: T10-Dif: RAM disk is allocating more space than required.Quinn Tran
Ram disk is allocating 8x more space than required for diff data. For large RAM disk test, there is small potential for memory starvation. (Use block_size when calculating total_sg_needed - sagi + nab) Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com> Signed-off-by: Quinn Tran <quinn.tran@qlogic.com> Cc: <stable@vger.kernel.org> #3.14+ Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-01-19target/rd: Add DIF protection into rd_execute_rwNicholas Bellinger
This patch adds support for DIF protection into rd_execute_rw() code for WRITE/READ I/O using sbc_dif_verify_[write,read]() logic. It also adds rd_get_prot_table() for locating protection SGLs assoicated with the ramdisk backend device. v2 changes: - Make rd_execute_rw() to u32 sectors count instead of sector_t - Drop SCF_PROT usage Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Sagi Grimberg <sagig@mellanox.com> Cc: Or Gerlitz <ogerlitz@mellanox.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-01-19target/rd: Add support for protection SGL setup + releaseNicholas Bellinger
This patch adds rd_build_prot_space() + rd_release_prot_space() logic to setup + release protection information scatterlists. It also adds rd_init_prot() + rd_free_prot() se_subsystem_api callbacks used by target core code for setup + release of protection information. v2 changes: - Drop unused sg_table from rd_release_prot_space (Wei) - Drop rd_release_prot_space call from rd_free_device Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Sagi Grimberg <sagig@mellanox.com> Cc: Or Gerlitz <ogerlitz@mellanox.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-01-19target/rd: Refactor rd_build_device_space + rd_release_device_spaceNicholas Bellinger
This patch refactors rd_build_device_space() + rd_release_device_space() into rd_allocate_sgl_table() + rd_release_device_space() so that they may be used seperatly for setup + release of protection information scatterlists. Also add explicit memset of pages within rd_allocate_sgl_table() based upon passed 'init_payload' value. v2 changes: - Drop unused sg_table from rd_release_device_space (Wei) Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Sagi Grimberg <sagig@mellanox.com> Cc: Or Gerlitz <ogerlitz@mellanox.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-11-12target: Core does not need blkdev.hAndy Grover
Target core does not depend on the block layer, only backstores that use the block layer do. Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-09-10target: Update copyright ownership/year information to 2013Nicholas Bellinger
Update copyright ownership/year information for target-core, loopback, iscsi-target, tcm_qla2xx, vhost and iser-target. Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-09-09target: Allow sbc_ops->execute_rw() to accept SGLs + data_directionNicholas Bellinger
COMPARE_AND_WRITE expects to be able to send down a DMA_FROM_DEVICE to obtain the necessary READ payload for comparision against the first half of the WRITE payload containing the verify user data. Currently virtual backends expect to internally reference SGLs, SGL nents, and data_direction, so change IBLOCK, FILEIO and RD sbc_ops->execute_rw() to accept this values as function parameters. Also add default sbc_execute_rw() handler for the typical case for cmd->execute_rw() submission using cmd->t_data_sg, cmd->t_data_nents, and cmd->data_direction). v2 Changes: - Add SCF_COMPARE_AND_WRITE command flag - Use sbc_execute_rw() for normal cmd->execute_rw() submission with expected se_cmd members. Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Martin Petersen <martin.petersen@oracle.com> Cc: Chris Mason <chris.mason@fusionio.com> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Nicholas Bellinger <nab@daterainc.com>
2013-06-14target: Don't allocate pages for NULLIO devicesAndy Grover
Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-05-11target/rd: Add ramdisk bit for NULLIO operationNicholas Bellinger
This patch adds a rd_nullio parameter that allows RAMDISK_MCP backends to function in NULLIO mode, where all se_cmd I/O is immediately completed in rd_execute_rw() without actually performing the SGL memory copy. This is useful for performance testing when the ramdisk SGL memory copy begins to eat lots of cycles during heavy small block workloads, so allow this bit to be enabled when necessary on a per rd_dev basis. Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-02-13target_core_rd: break out unterminated loop during copyHannes Reinecke
The loop in rd_execute_rw() will never terminate if the sg element has a zero size. Or it'll spill over into outer space if the sg element is larger than the available space. So we need to add some safety catches here. Cc: Nic Bellinger <nab@risingtidesystems.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-02-13target/rd: improve sg_table lookup scalabilityMartin Svec
Sequential scan of rd_dev->sg_table_array in rd_get_sg_table is a serious I/O performance bottleneck for large rd LUNs. Fix this by computing the sg_table index directly from page offset because all sg_tables (except the last one) have the same number of pages. Tested with 90 GiB rd_mcp LUN, where the patch improved maximal random R/W IOPS by more than 100-150%, depending on actual hardware and SAN setup. Signed-off-by: Martin Svec<martin.svec@zoner.cz> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-11-27target: Update copyright information to 2012Nicholas Bellinger
v2: Use correct target_core_stat.c 2006 copyright year v3: Drop extra unnessary legal verbage from header (hch) Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-11-06target: pass sense_reason as a return valueChristoph Hellwig
Pass the sense reason as an explicit return value from the I/O submission path instead of storing it in struct se_cmd and using negative return values. This cleans up a lot of the code pathes, and with the sparse annotations for the new sense_reason_t type allows for much better error checking. (nab: Convert spc_emulate_modesense + spc_emulate_modeselect to use sense_reason_t with Roland's MODE SELECT changes) Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-11-06target: remove ->get_device_revChristoph Hellwig
Now that the reservations and ALUA code have been cleaned up there is no need for the get_device_rev method, as we only need the standards revision in the inquiry data, where we can hardcode it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-11-06target: provide generic sbc device type/revision helpersChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-11-06target: rename spc_opsChristoph Hellwig
These really are sbc_ops, so name them correctly. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-11-06target: kill struct se_subsystem_devChristoph Hellwig
Simplify the code a lot by killing the superflous struct se_subsystem_dev. Instead se_device is allocated early on by the backend driver, which allocates it as part of its own per-device structure, borrowing the scheme that is for example used for inode allocation. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: add struct spc_ops + initial ->execute_rw pointer usageChristoph Hellwig
Remove the execute_cmd method in struct se_subsystem_api, and always use the one directly in struct se_cmd. To make life simpler for SBC virtual backends a struct spc_ops that is passed to sbc_parse_cmd is added. For now it only contains an execute_rw member, but more will follow with the subsequent commits. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: add a parse_cdb method to the backend driversChristoph Hellwig
Instead of trying to handle all SCSI command sets in one function (transport_generic_cmd_sequencer) call out to the backend driver to perform this functionality. For pSCSI a copy of the existing code is used, but for all virtual backends we can use a new parse_sbc_cdb helper is used to provide a simple SBC emulation. For now this setups means a fair amount of duplication between pSCSI and the SBC library, but patches later in this series will sort out that problem. (nab: Fix up build failure in target_core_pscsi.c) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove struct se_taskChristoph Hellwig
We can use struct se_cmd for everything it did. Make sure to pass the S/G list and data direction to the execution function to ease adding back BIDI support later on. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove the task_size field in struct se_taskChristoph Hellwig
Now that we don't split commands the size field in the task is always equivalent to the one in the CDB, even in cases where we have two tasks due to a BIDI transfer. Just refer the the size in the command instead of duplicating it in the task. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove the task_lba field in struct se_taskChristoph Hellwig
Now that we don't split commands the lba field in the task is always equivalent to the one in the CDB, even in cases where we have two tasks due to a BIDI transfer. Just refer the the lba in the command instead of duplicating it in the task. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-04-14target: don't limit transfer sizes for the ramdisk backendChristoph Hellwig
The ramdisk backend has not inherent limitations for handling requests, so don't artificially limits the transfer size. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-04-14target: misc ramdisk backend cleanupsChristoph Hellwig
Remove various leftovers of the old direct/indirect split, as well as the unused rd_request structure and a couple unused defines and fields. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14target: use \n as a separator for configurationSebastian Andrzej Siewior
The command | echo rd_pages=32768 > ramdisk/control Does not work because it writes "rd_pages=32768\n" and the parser which matches for "rd_pages=%d" does not recognize it due to the \n. One way of fixing this would be using "echo -n" instead. This patch adds \n to the list of separators so we don't have to use the -n argument which I find is more convinient. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14target: header reshuffle, part2Christoph Hellwig
This reorganized the headers under include/target into: - target_core_base.h stays as is with all target-wide data stuctures and defines - target_core_backend.h contains the whole interface to I/O backends - target_core_fabric.h contains the whole interface to fabric modules Except for those only the various configfs macro headers stay around. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06target/rd: fix or rewrite the copy routineSebastian Andrzej Siewior
So the code assumes that the sg list is only a array while in reality loopback SGL memory via scsi_cmnd into target-core may be already chained. This patch converts ramdisk code to use sg_miter logic from scatterlist.h in order to properly support passthrough SGL usage with transport_generic_map_mem_to_cmd() via loopback. With this patch the bug goes away. However after umount/mount of the device my files are gone. So something is still not right. After looking at it for a while I decided to rewrite the that part of the code and now things do work for me. For reference: - http://article.gmane.org/gmane.linux.scsi.target.devel/595 the sg_next() conversion - http://article.gmane.org/gmane.linux.scsi.target.devel/602 the rewrite of the copy code (nab: Fix compile warning in rd_MEMCPY) Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06target/rd: simplify the page/offset computationSebastian Andrzej Siewior
Breakout rd_MEMCPY_do_task() usage of do_div() to tmp value during rd_request->rd_page assignment. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-06target: Address legacy PYX_TRANSPORT_* return code breakageNicholas Bellinger
This patch removes legacy usage of PYX_TRANSPORT_* return codes in a number of locations and addresses cases where transport_generic_request_failure() was returning the incorrect sense upon CHECK_CONDITION status after the v3.1 converson to use errno return codes. This includes the conversion of transport_generic_request_failure() to process cmd->scsi_sense_reason and handle extra TCM_RESERVATION_CONFLICT before calling transport_send_check_condition_and_sense() to queue up response status. It also drops PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES legacy usgae, and returns TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE w/ a response for these cases. transport_generic_allocate_tasks(), transport_generic_new_cmd(), backend SCF_SCSI_DATA_SG_IO_CDB ->do_task(), and emulated ->execute_task() have all been updated to set se_cmd->scsi_sense_reason and return errno codes universally upon failure. This includes cmd->scsi_sense_reason assignment in target_core_alua.c, target_core_pr.c and target_core_cdb.c emulation code. Finally it updates fabric modules to remove the legacy usage, and for TFO->new_cmd_map() callers forwards return values outside of fabric code. iscsi-target has also been updated to remove a handful of special cases related to the cleanup and signaling QUEUE_FULL handling w/ ft_write_pending() (v2: Drop extra SCF_SCSI_CDB_EXCEPTION check during failure from transport_generic_new_cmd, and re-add missing task->task_error_status assignment in transport_complete_task) Cc: Christoph Hellwig <hch@lst.de> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24target: make the ->get_cdb method optionalChristoph Hellwig
The most commonly used file, iblock and rd backends have no use for a per-task CDB and thus don't need a method to copy it into their otherwise unused CDB fields. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24target: Cleanup unused se_task bitsChristoph Hellwig
This is a squashed version of the following se_task cleanup patches: target: remove the unused task_state_flags field in se_task target: remove the unused se_obj_ptr field in se_task target: remove the se_dev field in se_task Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-11target: Remove unneeded version.h includesJesper Juhl
It was pointed out by 'make versioncheck' that some includes of linux/version.h are not needed in drivers/target/. This patch removes them. Signed-off-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-08-22target: Convert target_core_rd.c to use use BUG_ONJulia Lawall
Use BUG_ON(x) rather than if(x) BUG(); The semantic patch that fixes this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ identifier x; @@ -if (x) BUG(); +BUG_ON(x); @@ identifier x; @@ -if (!x) BUG(); +BUG_ON(!x); // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Follow up core updates from AGrover and HCH (round 4)Andy Grover
This patch contains the squashed version of forth round series cleanups from Andy and Christoph following the post heavy lifting in the preceeding: 'Eliminate usage of struct se_mem' and 'Make all control CDBs scatter-gather' changes. This also includes a conversion of target core and the v3.0 mainline fabric modules (loopback and tcm_fc) to use pr_debug and the CONFIG_DYNAMIC_DEBUG infrastructure! These have been squashed into this third and final round for v3.1. target: Remove ifdeffed code in t_g_process_write target: Remove direct ramdisk code target: Rename task_sg_num to task_sg_nents target: Remove custom debug macros for pr_debug. Use pr_err(). target: Remove custom debug macros in mainline fabrics target: Set WSNZ=1 in block limits VPD. Abort if WRITE_SAME sectors = 0 target: Remove transport do_se_mem_map callback target: Further simplify transport_free_pages target: Redo task allocation return value handling target: Remove extra parentheses target: change alloc_task call to take *cdb, not *cmd (nab: Fix bogus struct file assignments in fd_do_readv and fd_do_writev) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Updates from AGrover and HCH (round 3)Andy Grover
This patch contains a squashed version of third round series cleanups, improvements ,and simplfications from Andy and Christoph ahead of the heavy lifting between round 3 -> 4 for the target core SGL conversion. This include cleanups to the main target I/O path and other miscellaneous updates. target: Replace custom sg<->buf functions with lib funcs target: Simplify sector limiting code target: get_cdb should never return NULL target: Simplify transport_memcpy_se_mem_read_contig target: Use assignment rather than increment for t_task_cdbs target: Don't pass dma_size to generic_get_mem target: Pass sg with type scatterlist in transport_map_sg_to_mem target: Move task_sg_num next to task_sg in struct se_task target: inline struct se_transport_task into struct se_cmd target: Change name & semantics of transport_get_sectors() target: Remove unused members of se_cmd target: Rename se_cmd.t_task_cdbs to t_task_list_num target: Fix some spelling target: Remove unused var from transport_generic_do_tmr target: map_sg_to_mem: return sg_count in return value target/pscsi: Use min_t for sector limits target/pscsi: Unused param for pscsi_get_bio() target: Rename get_cdb_count to allocate_tasks target: Make transport_generic_new_cmd() available for iscsi-target target: Remove fabric callback to allocate iovecs target: Fix transport_generic_new_cmd WRITE comment (hch: Use __GFP_ZERO usage for alloc_pages() usage) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: More core cleanups from AGrover (round 2)Andy Grover
This patch contains the squashed version of second round of target core cleanups and simplifications and Andy and Co. It also contains a handful of fixes to address bugs the original series and other minor cleanups. Here is the condensed shortlog: target: Remove unneeded casts to void* target: Rename get_lun_for_{cmd,tmr} to lookup_{cmd,tmr}_lun target: Make t_task a member of se_cmd, not a pointer target: Handle functions returning "-2" target: Use cmd->se_dev over cmd->se_lun->lun_se_dev target: Embed qr in struct se_cmd target: Replace embedded struct se_queue_req with a list_head target: Rename list_heads that are nodes in struct se_cmd to "*_node" target: Fold transport_device_setup_cmd() into lookup_{tmr,cmd}_lun() target: Make t_mem_list and t_mem_list_bidi members of t_task target: Add comment & cleanup transport_map_sg_to_mem() target: Remove unneeded checks in transport_free_pages() (Roland: Fix se_queue_req removal leftovers OOPs) (nab: Fix transport_lookup_tmr_lun failure case) (nab: Fix list_empty(&cmd->t_task.t_mem_bidi_list) inversion bugs) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Core cleanups from AGrover (round 1)Andy Grover
This patch contains the squashed version of a number of cleanups and minor fixes from Andy's initial series (round 1) for target core this past spring. The condensed log looks like: target: use errno values instead of returning -1 for everything target: Rename transport_calc_sg_num to transport_init_task_sg target: Fix leak in error path in transport_init_task_sg target/pscsi: Remove pscsi_get_sh() usage target: Make two runtime checks into WARN_ONs target: Remove hba queue depth and convert to spin_lock_irq usage target: dev->dev_status_queue_obj is unused target: Make struct se_queue_req.cmd type struct se_cmd * target: Remove __transport_get_qr_from_queue() target: Rename se_dev->g_se_dev_list to se_dev_node target: Remove struct se_global target: Simplify scsi mib index table code target: Make dev_queue_obj a member of se_device instead of a pointer target: remove extraneous returns at end of void functions target: Ensure transport_dump_vpd_ident_type returns null-terminated str target: Function pointers don't need to use '&' to be assigned target: Fix comment in __transport_execute_tasks() target: Misc style cleanups target: rename struct pr_reservation_template to pr_reservation target: Remove #defines that just perform indirection target: Inline transport_get_task_from_execute_queue() target: Minor header comment fixes Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-03-23[SCSI] target: Convert rd_build_device_space() to use errnoDan Carpenter
This patch converts rd_build_device_space() to return errno usage for failures in rd_create_virtdevice(). Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2011-03-23[SCSI] target: Convert backend ->create_virtdevice() call to return ERR_PTRNicholas Bellinger
This patch converts the target_core_store_dev_enable() -> struct se_subsystem_api->create_virtdevice() call to return proper ERR_PTR values back up to configfs logic during backend dependent struct se_device ENABLE exception conditions. Along with the change to target_core_configfs.c, this includes converting IBLOCK, FILEIO, pSCSI, and RAMDISK_* backend subsystem plugins to obtain upper level PTR_ERR return codes (where available), and return via ERR_PTR during a *_create_virtdev() failure. Reported-by: Fubo Chen <fubo.chen@gmail.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2011-03-02drivers: remove extraneous includes of smp_lock.hArnd Bergmann
These were missed the last time I cleaned this up globally, because of code moving around or new code getting merged. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2011-01-14[SCSI] target: Add LIO target core v4.0.0-rc6Nicholas Bellinger
LIO target is a full featured in-kernel target framework with the following feature set: High-performance, non-blocking, multithreaded architecture with SIMD support. Advanced SCSI feature set: * Persistent Reservations (PRs) * Asymmetric Logical Unit Assignment (ALUA) * Protocol and intra-nexus multiplexing, load-balancing and failover (MC/S) * Full Error Recovery (ERL=0,1,2) * Active/active task migration and session continuation (ERL=2) * Thin LUN provisioning (UNMAP and WRITE_SAMExx) Multiprotocol target plugins Storage media independence: * Virtualization of all storage media; transparent mapping of IO to LUNs * No hard limits on number of LUNs per Target; maximum LUN size ~750 TB * Backstores: SATA, SAS, SCSI, BluRay, DVD, FLASH, USB, ramdisk, etc. Standards compliance: * Full compliance with IETF (RFC 3720) * Full implementation of SPC-4 PRs and ALUA Significant code cleanups done by Christoph Hellwig. [jejb: fix up for new block bdev exclusive interface. Minor fixes from Randy Dunlap and Dan Carpenter.] Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org> Signed-off-by: James Bottomley <James.Bottomley@suse.de>