kernel.git/drivers/target/target_core_internal.h, branch linux-4.9.y

scsi: target: Fix ordered tag handling

2021-11-26T10:48:41Z

[ Upstream commit ed1227e080990ffec5bf39006ec8a57358e6689a ] 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 Signed-off-by: Sasha Levin

target: Fix kref->refcount underflow in transport_cmd_finish_abort

2017-06-29T11:00:30Z

commit 73d4e580ccc5c3e05cea002f18111f66c9c07034 upstream. This patch fixes a se_cmd->cmd_kref underflow during CMD_T_ABORTED when a fabric driver drops it's second reference from below the target_core_tmr.c based callers of transport_cmd_finish_abort(). Recently with the conversion of kref to refcount_t, this bug was manifesting itself as: [705519.601034] refcount_t: underflow; use-after-free. [705519.604034] INFO: NMI handler (kgdb_nmi_handler) took too long to run: 20116.512 msecs [705539.719111] ------------[ cut here ]------------ [705539.719117] WARNING: CPU: 3 PID: 26510 at lib/refcount.c:184 refcount_sub_and_test+0x33/0x51 Since the original kref atomic_t based kref_put() didn't check for underflow and only invoked the final callback when zero was reached, this bug did not manifest in practice since all se_cmd memory is using preallocated tags. To address this, go ahead and propigate the existing return from transport_put_cmd() up via transport_cmd_finish_abort(), and change transport_cmd_finish_abort() + core_tmr_handle_tas_abort() callers to only do their local target_put_sess_cmd() if necessary. Reported-by: Bart Van Assche Tested-by: Bart Van Assche Cc: Mike Christie Cc: Hannes Reinecke Cc: Christoph Hellwig Cc: Himanshu Madhani Cc: Sagi Grimberg Tested-by: Gary Guo Tested-by: Chu Yuan Lin Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: Fix ordered task target_setup_cmd_from_cdb exception hang

2016-07-20T07:58:38Z

If a command with a Simple task attribute is failed due to a Unit Attention, then a subsequent command with an Ordered task attribute will hang forever. The reason for this is that the Unit Attention status is checked for in target_setup_cmd_from_cdb, before the call to target_execute_cmd, which calls target_handle_task_attr, which in turn increments dev->simple_cmds. However, transport_generic_request_failure still calls transport_complete_task_attr, which will decrement dev->simple_cmds. In this case, simple_cmds is now -1. So when a command with the Ordered task attribute is sent, target_handle_task_attr sees that dev->simple_cmds is not 0, so it decides it can't execute the command until all the (nonexistent) Simple commands have completed. Reported-by: Michael Cyr Tested-by: Michael Cyr Reported-by: Bryant G. Ly Tested-by: Bryant G. Ly Cc: stable@vger.kernel.org # 4.4+ Signed-off-by: Nicholas Bellinger

target: make target db location configurable

2016-05-10T06:06:15Z

This commit adds the read-write attribute "dbroot", in the top-level CONFIGFS (core) target directory, normally /sys/kernel/config/target. This attribute defaults to "/var/target" but can be changed by writing a new pathname string to it. Changing this attribute is only allowed when no fabric drivers are loaded and the supplied value specifies an existing directory. Target modules that care about the target database root directory will be modified to use this attribute in a future commit. Signed-off-by: Lee Duncan Signed-off-by: Nicholas Bellinger

Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending

2016-03-22T19:41:14Z

Pull SCSI target updates from Nicholas Bellinger: "The highlights this round include: - Add target_alloc_session() w/ callback helper for doing se_session allocation + tag + se_node_acl lookup. (HCH + nab) - Tree-wide fabric driver conversion to use target_alloc_session() - Convert sbp-target to use percpu_ida tag pre-allocation, and TARGET_SCF_ACK_KREF I/O krefs (Chris Boot + nab) - Convert usb-gadget to use percpu_ida tag pre-allocation, and TARGET_SCF_ACK_KREF I/O krefs (Andrzej Pietrasiewicz + nab) - Convert xen-scsiback to use percpu_ida tag pre-allocation, and TARGET_SCF_ACK_KREF I/O krefs (Juergen Gross + nab) - Convert tcm_fc to use TARGET_SCF_ACK_KREF I/O + TMR krefs - Convert ib_srpt to use percpu_ida tag pre-allocation - Add DebugFS node for qla2xxx target sess list (Quinn) - Rework iser-target connection termination (Jenny + Sagi) - Convert iser-target to new CQ API (HCH) - Add pass-through WRITE_SAME support for IBLOCK (Mike Christie) - Introduce data_bitmap for asynchronous access of data area (Sheng Yang + Andy) - Fix target_release_cmd_kref shutdown comp leak (Himanshu Madhani) Also, there is a separate PULL request coming for cxgb4 NIC driver prerequisites for supporting hw iscsi segmentation offload (ISO), that will be the base for a number of v4.7 developments involving iscsi-target hw offloads" * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (36 commits) target: Fix target_release_cmd_kref shutdown comp leak target: Avoid DataIN transfers for non-GOOD SAM status target/user: Report capability of handling out-of-order completions to userspace target/user: Fix size_t format-spec build warning target/user: Don't free expired command when time out target/user: Introduce data_bitmap, replace data_length/data_head/data_tail target/user: Free data ring in unified function target/user: Use iovec[] to describe continuous area target: Remove enum transport_lunflags_table target/iblock: pass WRITE_SAME to device if possible iser-target: Kill the ->isert_cmd back pointer in struct iser_tx_desc iser-target: Kill struct isert_rdma_wr iser-target: Convert to new CQ API iser-target: Split and properly type the login buffer iser-target: Remove ISER_RECV_DATA_SEG_LEN iser-target: Remove impossible condition from isert_wait_conn iser-target: Remove redundant wait in release_conn iser-target: Rework connection termination iser-target: Separate flows for np listeners and connections cma events iser-target: Add new state ISER_CONN_BOUND to isert_conn ...

target: Remove enum transport_lunflags_table

2016-03-11T05:48:55Z

se_dev_entry.lun_flags and se_lun.lun_access are only used for keeping track of read-write vs. read-only state. Since this is an either/or thing we can represent it as bool, and remove the unneeded enum transport_lunflags_table, which is left over from when there were more flags. Change code that uses this enum to just use true/false, and make it clear through variable and param names that true means read-only, false means read-write. Signed-off-by: Andy Grover Reviewed-by: Christoph Hellwig Signed-off-by: Nicholas Bellinger

configfs: switch ->default groups to a linked list

2016-03-06T15:11:24Z

Replace the current NULL-terminated array of default groups with a linked list. This gets rid of lots of nasty code to size and/or dynamically allocate the array. While we're at it also provide a conveniant helper to remove the default groups. Signed-off-by: Christoph Hellwig Acked-by: Felipe Balbi [drivers/usb/gadget] Acked-by: Joel Becker Acked-by: Nicholas Bellinger Reviewed-by: Sagi Grimberg

target: Drop legacy se_cmd->task_stop_comp + REQUEST_STOP usage

2016-02-06T23:59:56Z

With CMD_T_FABRIC_STOP + se_cmd->cmd_wait_set usage in place, go ahead and drop left-over CMD_T_REQUEST_STOP checks in target_complete_cmd() and unused target_stop_cmd(). Reviewed-by: Christoph Hellwig Cc: Quinn Tran Cc: Himanshu Madhani Cc: Sagi Grimberg Cc: Hannes Reinecke Cc: Andy Grover Cc: Mike Christie Signed-off-by: Nicholas Bellinger

target: use per-attribute show and store methods

2015-10-14T05:17:49Z

This also allows to remove the target-specific old configfs macros, and gets rid of the target_core_fabric_configfs.h header which only had one function declaration left that could be moved to a better place. Signed-off-by: Christoph Hellwig Reviewed-by: Nicholas Bellinger Acked-by: Nicholas Bellinger Signed-off-by: Nicholas Bellinger

target: remove target_core_configfs.h

2015-06-23T07:43:51Z

The remaining defintions are private to the target core and can be merged into target_core_internal.h. Signed-off-by: Christoph Hellwig Reviewed-by: Andy Grover Signed-off-by: Nicholas Bellinger