target: Don't force session reset if queue_depth does not change

Keeping in the idempotent nature of target_core_fabric_configfs.c,
if a queue_depth value is set and it's the same as the

target: Don't force session reset if queue_depth does not change

Keeping in the idempotent nature of target_core_fabric_configfs.c,
if a queue_depth value is set and it's the same as the existing
value, don't attempt to force session reinstatement.

Reported-by: Raghu Krishnamurthy <rk@datera.io>
Cc: Raghu Krishnamurthy <rk@datera.io>
Tested-by: Gary Guo <ghg@datera.io>
Cc: Gary Guo <ghg@datera.io>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

target: Avoid mappedlun symlink creation during lun shutdown

This patch closes a race between se_lun deletion during configfs
unlink in target_fabric_port_unlink() -> core_dev_del_lun()

target: Avoid mappedlun symlink creation during lun shutdown

This patch closes a race between se_lun deletion during configfs
unlink in target_fabric_port_unlink() -> core_dev_del_lun()
-> core_tpg_remove_lun(), when transport_clear_lun_ref() blocks
waiting for percpu_ref RCU grace period to finish, but a new
NodeACL mappedlun is added before the RCU grace period has
completed.

This can happen in target_fabric_mappedlun_link() because it
only checks for se_lun->lun_se_dev, which is not cleared until
after transport_clear_lun_ref() percpu_ref RCU grace period
finishes.

This bug originally manifested as NULL pointer dereference
OOPsen in target_stat_scsi_att_intr_port_show_attr_dev() on
v4.1.y code, because it dereferences lun->lun_se_dev without
a explicit NULL pointer check.

In post v4.1 code with target-core RCU conversion, the code
in target_stat_scsi_att_intr_port_show_attr_dev() no longer
uses se_lun->lun_se_dev, but the same race still exists.

To address the bug, go ahead and set se_lun>lun_shutdown as
early as possible in core_tpg_remove_lun(), and ensure new
NodeACL mappedlun creation in target_fabric_mappedlun_link()
fails during se_lun shutdown.

Reported-by: James Shen <jcs@datera.io>
Cc: James Shen <jcs@datera.io>
Tested-by: James Shen <jcs@datera.io>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: allow ALUA setup for some passthrough backends

This patch allows passthrough backends to use the core/base LIO
ALUA setup and state checks, but still handle the execution of

target: allow ALUA setup for some passthrough backends

This patch allows passthrough backends to use the core/base LIO
ALUA setup and state checks, but still handle the execution of
commands.

This will allow the target_core_user module to execute STPG and RTPG
in userspace, and not have to duplicate the ALUA state checks, path
information (needed so we can check if command is executable on
specific paths) and setup (rtslib sets/updates the configfs ALUA
interface like it does for iblock or file).

For STPG, the target_core_user userspace daemon, tcmu-runner will
still execute the STPG, and to update the core/base LIO state it
will use the existing configfs interface. For RTPG, tcmu-runner
will loop over configfs and/or cache the state.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

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

Pull SCSI target updates from Nicholas Bellinger:
"The highlights this round include:

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

Pull SCSI target updates from Nicholas Bellinger:
"The highlights this round include:

- enable dual mode (initiator + target) qla2xxx operation. (Quinn +
Himanshu)

- add a framework for qla2xxx async fabric discovery. (Quinn +
Himanshu)

- enable iscsi PDU DDP completion offload in cxgbit/T6 NICs. (Varun)

- fix target-core handling of aborted failed commands. (Bart)

- fix a long standing target-core issue NULL pointer dereference with
active I/O LUN shutdown. (Rob Millner + Bryant + nab)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (44 commits)
target: Add counters for ABORT_TASK success + failure
iscsi-target: Fix early login failure statistics misses
target: Fix NULL dereference during LUN lookup + active I/O shutdown
target: Delete tmr from list before processing
target: Fix handling of aborted failed commands
uapi: fix linux/target_core_user.h userspace compilation errors
target: export protocol identifier
qla2xxx: Fix a warning reported by the "smatch" static checker
target/iscsi: Fix unsolicited data seq_end_offset calculation
target/cxgbit: add T6 iSCSI DDP completion feature
target/cxgbit: Enable DDP for T6 only if data sequence and pdu are in order
target/cxgbit: Use T6 specific macros to get ETH/IP hdr len
target/cxgbit: use cxgb4_tp_smt_idx() to get smt idx
target/iscsi: split iscsit_check_dataout_hdr()
target: Remove command flag CMD_T_DEV_ACTIVE
target: Remove command flag CMD_T_BUSY
target: Move session check from target_put_sess_cmd() into target_release_cmd_kref()
target: Inline transport_cmd_check_stop()
target: Remove an overly chatty debug message
target: Stop execution if CMD_T_STOP has been set
...

show more ...

target: Fix NULL dereference during LUN lookup + active I/O shutdown

When transport_clear_lun_ref() is shutting down a se_lun via
configfs with new I/O in-flight, it's possible to trigge

target: Fix NULL dereference during LUN lookup + active I/O shutdown

When transport_clear_lun_ref() is shutting down a se_lun via
configfs with new I/O in-flight, it's possible to trigger a
NULL pointer dereference in transport_lookup_cmd_lun() due
to the fact percpu_ref_get() doesn't do any __PERCPU_REF_DEAD
checking before incrementing lun->lun_ref.count after
lun->lun_ref has switched to atomic_t mode.

This results in a NULL pointer dereference as LUN shutdown
code in core_tpg_remove_lun() continues running after the
existing ->release() -> core_tpg_lun_ref_release() callback
completes, and clears the RCU protected se_lun->lun_se_dev
pointer.

During the OOPs, the state of lun->lun_ref in the process
which triggered the NULL pointer dereference looks like
the following on v4.1.y stable code:

struct se_lun {
lun_link_magic = 4294932337,
lun_status = TRANSPORT_LUN_STATUS_FREE,

.....

lun_se_dev = 0x0,
lun_sep = 0x0,

.....

lun_ref = {
count = {
counter = 1
},
percpu_count_ptr = 3,
release = 0xffffffffa02fa1e0 <core_tpg_lun_ref_release>,
confirm_switch = 0x0,
force_atomic = false,
rcu = {
next = 0xffff88154fa1a5d0,
func = 0xffffffff8137c4c0 <percpu_ref_switch_to_atomic_rcu>
}
}
}

To address this bug, use percpu_ref_tryget_live() to ensure
once __PERCPU_REF_DEAD is visable on all CPUs and ->lun_ref
has switched to atomic_t, all new I/Os will fail to obtain
a new lun->lun_ref reference.

Also use an explicit percpu_ref_kill_and_confirm() callback
to block on ->lun_ref_comp to allow the first stage and
associated RCU grace period to complete, and then block on
->lun_ref_shutdown waiting for the final percpu_ref_put()
to drop the last reference via transport_lun_remove_cmd()
before continuing with core_tpg_remove_lun() shutdown.

Reported-by: Rob Millner <rlm@daterainc.com>
Tested-by: Rob Millner <rlm@daterainc.com>
Cc: Rob Millner <rlm@daterainc.com>
Tested-by: Vaibhav Tandon <vst@datera.io>
Cc: Vaibhav Tandon <vst@datera.io>
Tested-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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IB/srpt: Accept GUIDs as port names

Port and ACL information must be configured before an initiator
logs in. Make it possible to configure this information before
a subnet prefix ha

IB/srpt: Accept GUIDs as port names

Port and ACL information must be configured before an initiator
logs in. Make it possible to configure this information before
a subnet prefix has been assigned to a port by not only accepting
GIDs as target port and initiator port names but by also accepting
port GUIDs.

Add a 'priv' member to struct se_wwn to allow target drivers to
associate their own data with struct se_wwn.

Reported-by: Doug Ledford <dledford@redhat.com>
References: http://www.spinics.net/lists/linux-rdma/msg39505.html
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

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target: remove sess_kref and ->shutdown_session

Both of them are unused now that drivers handle any delayed session
shutdown internally.

Signed-off-by: Christoph Hellwig <hch@ls

target: remove sess_kref and ->shutdown_session

Both of them are unused now that drivers handle any delayed session
shutdown internally.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: make ->shutdown_session optional

Turns out the template and thus many drivers got the return value wrong:
0 means the fabrics driver needs to put a session reference, which no

target: make ->shutdown_session optional

Turns out the template and thus many drivers got the return value wrong:
0 means the fabrics driver needs to put a session reference, which no
driver except for the iSCSI target drivers did. Fortunately none of these
drivers supports explicit Node ACLs, so the bug was harmless.

Even without that only qla2xxx and iscsi every did real work in
shutdown_session, so get rid of the boilerplate code in all other
drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: remove acl_stop

Ensure we can use list_empty on the sess_acl_list to remove the need for
this flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nich

target: remove acl_stop

Ensure we can use list_empty on the sess_acl_list to remove the need for
this flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

target: consolidate and fix session shutdown

Factor out a helper to shutdown sessions for a Node ACL, and make it
properly restart the list walk after dropping the lock.

Signed-

target: consolidate and fix session shutdown

Factor out a helper to shutdown sessions for a Node ACL, and make it
properly restart the list walk after dropping the lock.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

target: Remove enum transport_lunflags_table

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 th

target: Remove enum transport_lunflags_table

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 <agrover@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

target: Obtain se_node_acl->acl_kref during get_initiator_node_acl

This patch addresses a long standing race where obtaining
se_node_acl->acl_kref in __transport_register_session()
h

target: Obtain se_node_acl->acl_kref during get_initiator_node_acl

This patch addresses a long standing race where obtaining
se_node_acl->acl_kref in __transport_register_session()
happens a bit too late, and leaves open the potential
for core_tpg_del_initiator_node_acl() to hit a NULL
pointer dereference.

Instead, take ->acl_kref in core_tpg_get_initiator_node_acl()
while se_portal_group->acl_node_mutex is held, and move the
final target_put_nacl() from transport_deregister_session()
into transport_free_session() so that fabric driver login
failure handling using the modern method to still work
as expected.

Also, update core_tpg_get_initiator_node_acl() to take
an extra reference for dynamically generated acls for
demo-mode, before returning to fabric caller. Also
update iscsi-target sendtargets special case handling
to use target_tpg_has_node_acl() when checking if
demo_mode_discovery == true during discovery lookup.

Note the existing wait_for_completion(&acl->acl_free_comp)
in core_tpg_del_initiator_node_acl() does not change.

Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

target: Convert ACL change queue_depth se_session reference usage

This patch converts core_tpg_set_initiator_node_queue_depth()
to use struct se_node_acl->acl_sess_list when performing

target: Convert ACL change queue_depth se_session reference usage

This patch converts core_tpg_set_initiator_node_queue_depth()
to use struct se_node_acl->acl_sess_list when performing
explicit se_tpg_tfo->shutdown_session() for active sessions,
in order for new se_node_acl->queue_depth to take effect.

This follows how core_tpg_del_initiator_node_acl() currently
works when invoking se_tpg_tfo->shutdown-session(), and ahead
of the next patch to take se_node_acl->acl_kref during lookup,
the extra get_initiator_node_acl() can go away. In order to
achieve this, go ahead and change target_get_session() to use
kref_get_unless_zero() and propigate up the return value
to know when a session is already being released.

This is because se_node_acl->acl_group is already protecting
se_node_acl->acl_group reference via configfs, and shutdown
within core_tpg_del_initiator_node_acl() won't occur until
sys_write() to core_tpg_set_initiator_node_queue_depth()
attribute returns back to user-space.

Also, drop the left-over iscsi-target hack, and obtain
se_portal_group->session_lock in lio_tpg_shutdown_session()
internally. Remove iscsi-target wrapper and unused se_tpg +
force parameters and associated code.

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

target: Remove an unused variable

The num_node_acls member in struct se_portal_group is modified
by several functions but is never read. Hence remove it.

Signed-off-by: Bart Van

target: Remove an unused variable

The num_node_acls member in struct se_portal_group is modified
by several functions but is never read. Hence remove it.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: Propigate backend read-only to core_tpg_add_lun

This patch adds a DF_READ_ONLY flag that is used by IBLOCK to
signal when a backend has been set to read-only mode, in order
t

target: Propigate backend read-only to core_tpg_add_lun

This patch adds a DF_READ_ONLY flag that is used by IBLOCK to
signal when a backend has been set to read-only mode, in order
to propigate read-only status up to core_tpg_add_lun() for all
future LUN fabric exports.

With this is place, existing emulation for reporting read-only
in spc_emulate_modesense() and normal transport_lookup_cmd_lun()
TCM_WRITE_PROTECTED status checking just works as expected.

Reported-by: Joeue Deng <joeue404@gmail.com>
Reported-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

tcm_loop: Send I_T_NEXUS_LOSS_OCCURRED UA

If the virtual SAS link is set to 'offline' we should be
queueing an I_T_NEXUS_LOSS_OCCURRED UA.

Signed-off-by: Hannes Reinecke <hare@s

tcm_loop: Send I_T_NEXUS_LOSS_OCCURRED UA

If the virtual SAS link is set to 'offline' we should be
queueing an I_T_NEXUS_LOSS_OCCURRED UA.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

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

Pull SCSI target updates from Nicholas Bellinger:
"It's been a busy development cycle for tar

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

Pull SCSI target updates from Nicholas Bellinger:
"It's been a busy development cycle for target-core in a number of
different areas.

The fabric API usage for se_node_acl allocation is now within
target-core code, dropping the external API callers for all fabric
drivers tree-wide.

There is a new conversion to RCU hlists for se_node_acl and
se_portal_group LUN mappings, that turns fast-past LUN lookup into a
completely lockless code-path. It also removes the original
hard-coded limitation of 256 LUNs per fabric endpoint.

The configfs attributes for backends can now be shared between core
and driver code, allowing existing drivers to use common code while
still allowing flexibility for new backend provided attributes.

The highlights include:

- Merge sbc_verify_dif_* into common code (sagi)
- Remove iscsi-target support for obsolete IFMarker/OFMarker
(Christophe Vu-Brugier)
- Add bidi support in target/user backend (ilias + vangelis + agover)
- Move se_node_acl allocation into target-core code (hch)
- Add crc_t10dif_update common helper (akinobu + mkp)
- Handle target-core odd SGL mapping for data transfer memory
(akinobu)
- Move transport ID handling into target-core (hch)
- Move task tag into struct se_cmd + support 64-bit tags (bart)
- Convert se_node_acl->device_list[] to RCU hlist (nab + hch +
paulmck)
- Convert se_portal_group->tpg_lun_list[] to RCU hlist (nab + hch +
paulmck)
- Simplify target backend driver registration (hch)
- Consolidate + simplify target backend attribute implementations
(hch + nab)
- Subsume se_port + t10_alua_tg_pt_gp_member into se_lun (hch)
- Drop lun_sep_lock for se_lun->lun_se_dev RCU usage (hch + nab)
- Drop unnecessary core_tpg_register TFO parameter (nab)
- Use 64-bit LUNs tree-wide (hannes)
- Drop left-over TARGET_MAX_LUNS_PER_TRANSPORT limit (hannes)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (76 commits)
target: Bump core version to v5.0
target: remove target_core_configfs.h
target: remove unused TARGET_CORE_CONFIG_ROOT define
target: consolidate version defines
target: implement WRITE_SAME with UNMAP bit using ->execute_unmap
target: simplify UNMAP handling
target: replace se_cmd->execute_rw with a protocol_data field
target/user: Fix inconsistent kmap_atomic/kunmap_atomic
target: Send UA when changing LUN inventory
target: Send UA upon LUN RESET tmr completion
target: Send UA on ALUA target port group change
target: Convert se_lun->lun_deve_lock to normal spinlock
target: use 'se_dev_entry' when allocating UAs
target: Remove 'ua_nacl' pointer from se_ua structure
target_core_alua: Correct UA handling when switching states
xen-scsiback: Fix compile warning for 64-bit LUN
target: Remove TARGET_MAX_LUNS_PER_TRANSPORT
target: use 64-bit LUNs
target: Drop duplicate + unused se_dev_check_wce
target: Drop unnecessary core_tpg_register TFO parameter
...

show more ...

target: remove target_core_configfs.h

The remaining defintions are private to the target core and can be merged
into target_core_internal.h.

Signed-off-by: Christoph Hellwig <hc

target: remove target_core_configfs.h

The remaining defintions are private to the target core and can be merged
into target_core_internal.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: Remove TARGET_MAX_LUNS_PER_TRANSPORT

LUN allocation is now fully dynamic, so there is no need to
artificially restrain the number of exported LUNs.

Signed-off-by: Hannes

target: Remove TARGET_MAX_LUNS_PER_TRANSPORT

LUN allocation is now fully dynamic, so there is no need to
artificially restrain the number of exported LUNs.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: use 64-bit LUNs

As we're now using a list to hold the LUNs the target core
can now converted to use 64-bit LUNs internally.

Signed-off-by: Hannes Reinecke <hare@suse.de>

target: use 64-bit LUNs

As we're now using a list to hold the LUNs the target core
can now converted to use 64-bit LUNs internally.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

show more ...

target: Drop unnecessary core_tpg_register TFO parameter

This patch drops unnecessary target_core_fabric_ops parameter usage
for core_tpg_register() during fabric driver TFO->fabric_make

target: Drop unnecessary core_tpg_register TFO parameter

This patch drops unnecessary target_core_fabric_ops parameter usage
for core_tpg_register() during fabric driver TFO->fabric_make_tpg()
se_portal_group creation callback execution.

Instead, use the existing se_wwn->wwn_tf->tf_ops pointer to ensure
fabric driver is really using the same TFO provided at module_init
time.

Also go ahead and drop the forward TFO declarations tree-wide, and
handling the special case for iscsi-target discovery TPG.

Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: Minimize SCSI header #include directives

Only include SCSI initiator header files in target code that needs
these header files, namely the SCSI pass-through code and the tcm_loop

target: Minimize SCSI header #include directives

Only include SCSI initiator header files in target code that needs
these header files, namely the SCSI pass-through code and the tcm_loop
driver. Change SCSI_SENSE_BUFFERSIZE into TRANSPORT_SENSE_BUFFER in
target code because the former is intended for initiator code and the
latter for target code. With this patch the only initiator include
directives in target code that remain are as follows:

$ git grep -nHE 'include .scsi/(scsi.h|scsi_host.h|scsi_device.h|scsi_cmnd.h)' drivers/target drivers/infiniband/ulp/{isert,srpt} drivers/usb/gadget/legacy/tcm_*.[ch] drivers/{vhost,xen} include/{target,trace/events/target.h}
drivers/target/loopback/tcm_loop.c:29:#include <scsi/scsi.h>
drivers/target/loopback/tcm_loop.c:31:#include <scsi/scsi_host.h>
drivers/target/loopback/tcm_loop.c:32:#include <scsi/scsi_device.h>
drivers/target/loopback/tcm_loop.c:33:#include <scsi/scsi_cmnd.h>
drivers/target/target_core_pscsi.c:39:#include <scsi/scsi_device.h>
drivers/target/target_core_pscsi.c:40:#include <scsi/scsi_host.h>
drivers/xen/xen-scsiback.c:52:#include <scsi/scsi_host.h> /* SG_ALL */

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

show more ...

target: Drop se_lun->lun_active for existing percpu lun_ref

With se_port_t and t10_alua_tg_pt_gp_member being absored into se_lun,
there is no need for an extra atomic_t based reference

target: Drop se_lun->lun_active for existing percpu lun_ref

With se_port_t and t10_alua_tg_pt_gp_member being absored into se_lun,
there is no need for an extra atomic_t based reference count for PR
ALL_TG_PT=1 and ALUA access state transition.

Go ahead and use the existing percpu se_lun->lun_ref instead, and
convert the two special cases to percpu_ref_tryget_live() to avoid
se_lun if transport_clear_lun_ref() has already been invoked to
shutdown the se_lun.

Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: Drop lun_sep_lock for se_lun->lun_se_dev RCU usage

With se_port and t10_alua_tg_pt_gp_member being absored into se_lun,
there is no need for an extra lock to protect se_lun->lun_

target: Drop lun_sep_lock for se_lun->lun_se_dev RCU usage

With se_port and t10_alua_tg_pt_gp_member being absored into se_lun,
there is no need for an extra lock to protect se_lun->lun_se_dev
assignment.

This patch also converts backend drivers to use call_rcu() release
to allow any se_device readers to complete. The call_rcu() instead
of kfree_rcu() is required here because se_device is embedded into
the backend driver specific structure.

Also, convert se_lun->lun_stats to use atomic_long_t within the
target_complete_ok_work() completion callback, and add FIXME for
transport_lookup_tmr_lun() with se_lun->lun_ref.

Finally, update sbp_update_unit_directory() special case usage with
proper rcu_dereference_raw() and configfs symlink comment.

Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Chris Boot <bootc@bootc.net>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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target: Subsume se_port + t10_alua_tg_pt_gp_member into se_lun

This patch eliminates all se_port + t10_alua_tg_pt_gp_member usage,
and converts current users to direct se_lun pointer der

target: Subsume se_port + t10_alua_tg_pt_gp_member into se_lun

This patch eliminates all se_port + t10_alua_tg_pt_gp_member usage,
and converts current users to direct se_lun pointer dereference.

This includes the removal of core_export_port(), core_release_port()
core_dev_export() and core_dev_unexport(). Along with conversion
of special case se_lun pointer dereference within PR ALL_TG_PT=1
and ALUA access state transition UNIT_ATTENTION handling.

Also, update core_enable_device_list_for_node() to reference the
new per se_lun->lun_deve_list when creating a new entry, or
replacing an existing one via RCU.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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