scsi: target: Have drivers report if they support direct submissions

In some cases, like with multiple LUN targets or where the target has to
respond to transport level requests from the receiving context it can be
better to defer cmd submission to a helper thread. If the backend driver
blocks on something like request/tag allocation it can block the entire
target submission path and other LUs and transport IO on that session.

In other cases like single LUN targets with storage that can support all
the commands that the target can queue, then it's best to submit the cmd
to the backend from the target's cmd receiving context.

Subsequent commits will allow the user to config what they prefer, but
drivers like loop can't directly submit because they can be called from a
context that can't sleep. And, drivers like vhost-scsi can support direct
submission, but need to keep their default behavior of deferring execution
to avoid possible regressions where the backend can block.

Make the drivers tell LIO core if they support direct submissions and their
current default, so we can prevent users from misconfiguring the system and
initialize devices correctly.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20230928020907.5730-2-michael.christie@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

xen/scsiback: don't call scsiback_free_translation_entry() under lock

scsiback_free_translation_entry() shouldn't be called under spinlock,
as it can sleep.

This requires to split removing a translation entry from the v2p list
from actually calling kref_put() for the entry.

Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20230328084602.20729-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

scsi: xen-scsiback: Remove default fabric ops callouts

Remove callouts that are identical to the default implementations in TCM
Core.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com>
Link: https://lore.kernel.org/r/20230313181110.20566-10-d.bogdanov@yadro.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

xen: make remove callback of xen driver void returned

Since commit fc7a6209d571 ("bus: Make remove callback return void")
forces bus_type::remove be void-returned, it doesn't make much sense for
any bus based driver implementing remove callbalk to return non-void to
its caller.

This change is for xen bus based drivers.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Link: https://lore.kernel.org/r/TYCP286MB23238119AB4DF190997075C9CAE39@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Juergen Gross <jgross@suse.com>

scsi: xen: Drop use of internal host codes

The error codes:

- DID_TARGET_FAILURE

- DID_NEXUS_FAILURE

- DID_ALLOC_FAILURE

- DID_MEDIUM_ERROR

are internal to the SCSI layer. Drivers must not use them because:

1. They are not propagated upwards, so SG IO/passthrough users will not
see an error and think a command was successful.

xen-scsiback will never see this error and should not try to send it.

2. There is no handling for them in scsi_decide_disposition() so if
xen-scsifront were to return the error to the SCSI midlayer then it
kicks off the error handler which is definitely not what we want.

Remove the use from xen-scsifront/back.

Link: https://lore.kernel.org/r/20220812010027.8251-2-michael.christie@oracle.com
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

xen: move from strlcpy with unused retval to strscpy

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20220818210122.7613-1-wsa+renesas@sang-engineering.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/scsiback: use new command result macros

Instead of using the kernel's values for the result of PV scsi
operations use the values of the interface definition.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20220428075323.12853-3-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

isystem: trim/fixup stdarg.h and other headers

Delete/fixup few includes in anticipation of global -isystem compile
option removal.

Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition
of uintptr_t error (one definition comes from <stddef.h>, another from
<linux/types.h>).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scsi: core: Drop obsolete Linux-specific SCSI status codes

Originally the SCSI subsystem has been using 'special' SCSI status codes,
which were the SAM-specified ones but shifted by 1. As most drivers have
now been modified to use the SAM-specified ones, having two nearly
identical sets of definitions only causes confusion.

The Linux-specifed SCSI status codes have been marked obsolete for several
years so drop them and use the SAM-specified status codes throughout.

Link: https://lore.kernel.org/r/20210427083046.31620-41-hare@suse.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: core: Drop message byte helper

The message byte is now unused, so we can drop the helper to set the
message byte and the check for message bytes during error recovery.

Link: https://lore.kernel.org/r/20210427083046.31620-38-hare@suse.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: core: Drop the now obsolete driver_byte definitions

The driver_byte field in the result is now unused, so we can drop the
definitions.

Link: https://lore.kernel.org/r/20210427083046.31620-15-hare@suse.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: xen-scsiback: Use DID_ERROR instead of DRIVER_ERROR

DRIVER_ERROR was supposed to signal an error generated by the driver, which
xen-scsiback arguably isn't. Also the driver bytes don't have a detailed
error recovery, so we should rather return DID_ERROR instead of
DRIVER_ERROR.

Link: https://lore.kernel.org/r/20210427083046.31620-13-hare@suse.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: core: Kill DRIVER_SENSE

Replace the check for DRIVER_SENSE with a check for
scsi_status_is_check_condition().

Audit all callsites to ensure the SAM status is set correctly. For
backwards compability move the DRIVER_SENSE definition to sg.h, and update
sg, bsg, and scsi_ioctl to set the DRIVER_SENSE driver_status whenever
SAM_STAT_CHECK_CONDITION is present.

[mkp: fix zeroday srp warning]

Link: https://lore.kernel.org/r/20210427083046.31620-10-hare@suse.de
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

fix

scsi: target: core: Add gfp_t arg to target_cmd_init_cdb()

tcm_loop could be used like a normal block device, so we can't use
GFP_KERNEL and should use GFP_NOIO. This adds a gfp_t arg to
target_cmd_init_cdb() and converts the users. For every driver but loop
GFP_KERNEL is kept.

This will also be useful in subsequent patches where loop needs to do
target_submit_prep() from interrupt context to get a ref to the se_device,
and so it will need to use GFP_ATOMIC.

Link: https://lore.kernel.org/r/20210227170006.5077-16-michael.christie@oracle.com
Tested-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: xen-scsiback: Convert to new submission API

target_submit_cmd_map_sgls() is being removed, so convert xen to the new
submission API. This has it use target_init_cmd(), target_submit_prep(), or
target_submit() because we need to have LIO core map sgls which is now done
in target_submit_prep(). target_init_cmd() will never fail for xen because
it does its own sync during session shutdown, so we can remove that code.

Note: xen never calls target_stop_session() so target_submit_cmd_map_sgls()
never failed (in the new API target_init_cmd() handles
target_stop_session() being called when cmds are being submitted). If it
were to have used target_stop_session() and got an error, we would have hit
a refcount bug like xen and usb, because it does:

if (rc < 0) {
transport_send_check_condition_and_sense(se_cmd,
TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
transport_generic_free_cmd(se_cmd, 0);
}

transport_send_check_condition_and_sense() calls queue_status which calls
scsiback_cmd_done->target_put_sess_cmd. We do an extra
transport_generic_free_cmd() call above which would have dropped the
refcount to -1 and the refcount code would spit out errors.

Link: https://lore.kernel.org/r/20210227170006.5077-13-michael.christie@oracle.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

xen-scsiback: don't "handle" error by BUG()

In particular -ENOMEM may come back here, from set_foreign_p2m_mapping().
Don't make problems worse, the more that handling elsewhere (together
with map's status fields now indicating whether a mapping wasn't even
attempted, and hence has to be considered failed) doesn't require this
odd way of dealing with errors.

This is part of XSA-362.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/events: link interdomain events to associated xenbus device

In order to support the possibility of per-device event channel
settings (e.g. lateeoi spurious event thresholds) add a xenbus device
pointer to struct irq_info() and modify the related event channel
binding interfaces to take the pointer to the xenbus device as a
parameter instead of the domain id of the other side.

While at it remove the stale prototype of bind_evtchn_to_irq_lateeoi().

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

xen: add helpers for caching grant mapping pages

Instead of having similar helpers in multiple backend drivers use
common helpers for caching pages allocated via gnttab_alloc_pages().

Make use of those helpers in blkback and scsiback.

Cc: <stable@vger.kernel.org> # 5.9
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovksy@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/scsiback: use lateeoi irq binding

In order to reduce the chance for the system becoming unresponsive due
to event storms triggered by a misbehaving scsifront use the lateeoi
irq binding for scsiback and unmask the event channel only just before
leaving the event handling function.

In case of a ring protocol error don't issue an EOI in order to avoid
the possibility to use that for producing an event storm. This at once
will result in no further call of scsiback_irq_fn(), so the ring_error
struct member can be dropped and scsiback_do_cmd_fn() can signal the
protocol error via a negative return value.

This is part of XSA-332.

Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

xen: Use evtchn_type_t as a type for event channels

Make event channel functions pass event channel port using
evtchn_port_t type. It eliminates signed <-> unsigned conversion.

Signed-off-by: Yan Yankovskyi <yyankovskyi@gmail.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20200323152343.GA28422@kbp1-lhp-F74019
Signed-off-by: Juergen Gross <jgross@suse.com>

xen-scsiback: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warning:

drivers/xen/xen-scsiback.c: In function ‘scsiback_frontend_changed’:
drivers/xen/xen-scsiback.c:1185:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
if (xenbus_dev_is_online(dev))
^
drivers/xen/xen-scsiback.c:1188:2: note: here
case XenbusStateUnknown:
^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

Notice that, in this particular case, the code comment is modified
in accordance with what GCC is expecting to find.

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

scsi: target/core: Remove the write_pending_status() callback function

Due to the patch that makes TMF handling synchronous the
write_pending_status() callback function is no longer called. Hence remove
it.

Acked-by: Felipe Balbi <balbi@ti.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Andy Grover <agrover@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Himanshu Madhani <himanshu.madhani@qlogic.com>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Saurav Kashyap <saurav.kashyap@qlogic.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: replace fabric_ops.name with fabric_alias

iscsi_target_mod is the only LIO fabric where fabric_ops.name differs from
the fabric_ops.fabric_name string. fabric_ops.name is used when matching
target/$fabric ConfigFS create paths, so rename it .fabric_alias and
fallback to target/$fabric vs .fabric_name comparison if .fabric_alias
isn't initialised. iscsi_target_mod is the only fabric module to set
.fabric_alias . All other fabric modules rely on .fabric_name matching and
can drop the duplicate string.

Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: drop unnecessary get_fabric_name() accessor from fabric_ops

All fabrics return a const string. In all cases *except* iSCSI the
get_fabric_name() string matches fabric_ops.name.

Both fabric_ops.get_fabric_name() and fabric_ops.name are user-facing, with
the former being used for PR/ALUA state and the latter for ConfigFS
(config/target/$name), so we unfortunately need to keep both strings around
for now. Replace the useless .get_fabric_name() accessor function with a
const string fabric_name member variable.

Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: loop, usb, vhost, xen: use target_remove_session

This converts drivers that were only calling transport_deregister_session
to use target_remove_session. The calling of
transport_deregister_session_configfs via target_remove_session for these
types of drivers is ok, because they were not exporting info from fields
like sess_acl_list, sess->se_tpg and sess->fabric_sess_ptr from configfs
accessible functions, so they will see no difference.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: rename target_alloc_session

Rename target_alloc_session to target_setup_session to avoid confusion with
the other transport session allocation function that only allocates the
session and because the target_alloc_session does so much more. It
allocates the session, sets up the nacl and registers the session.

The next patch will then add a remove function to match the setup in this
one, so it should make sense for all drivers, except iscsi, to just call
those 2 functions to setup and remove a session.

iscsi will continue to be the odd driver.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Chris Boot <bootc@bootc.net>
Cc: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Cc: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Cc: <qla2xxx-upstream@qlogic.com>
Cc: Johannes Thumshirn <jth@kernel.org>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: Remove second argument from fabric_make_tpg()

Since most target drivers do not use the second fabric_make_tpg() argument
("group") and since it is trivial to derive the group pointer from the wwn
pointer, do not pass the group pointer to fabric_make_tpg().

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: Convert target drivers to use sbitmap

The sbitmap and the percpu_ida perform essentially the same task,
allocating tags for commands. The sbitmap outperforms the percpu_ida as
documented here: https://lkml.org/lkml/2014/4/22/553

The sbitmap interface is a little harder to use, but being able to remove
the percpu_ida code and getting better performance justifies the additional
complexity.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> # f_tcm
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: target: Abstract tag freeing

Introduce target_free_tag() and convert all drivers to use it.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

xen/scsiback: add error handling for xenbus_printf

When xenbus_printf fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling xenbus_printf.

Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/scsiback: Make TMF processing slightly faster

Target drivers must guarantee that struct se_cmd and struct se_tmr_req
exist as long as target_tmr_work() is in progress. Since the last
access by the LIO core is a call to .check_stop_free() and since the
Xen scsiback .check_stop_free() drops a reference to the TMF, it is
already guaranteed that the struct se_cmd that corresponds to the TMF
exists as long as target_tmr_work() is in progress. Hence change the
second argument of transport_generic_free_cmd() from 1 into 0.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: David Disseldorp <ddiss@suse.de>
Cc: xen-devel@lists.xenproject.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

xen/scsiback: Replace a waitqueue and a counter by a completion

This patch simplifies the implementation of the scsiback driver
but does not change its behavior.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: David Disseldorp <ddiss@suse.de>
Cc: xen-devel@lists.xenproject.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

xen/scsiback: Fix a TMR related use-after-free

scsiback_release_cmd() must not dereference se_cmd->se_tmr_req
because that memory is freed by target_free_cmd_mem() before
scsiback_release_cmd() is called. Fix this use-after-free by
inlining struct scsiback_tmr into struct vscsibk_pend.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: David Disseldorp <ddiss@suse.de>
Cc: xen-devel@lists.xenproject.org
Cc: <stable@vger.kernel.org> # 3.18+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

target: make close_session optional

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

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>

xen-scsiback: Convert to TARGET_SCF_ACK_KREF I/O krefs

This patch converts xen-scsiback to modern TARGET_SCF_ACK_KREF
usage for scsiback_cmd_done() callback path.

It also also converts TMR -> scsiback_device_action() to use
modern target_submit_tmr() code.

Acked-by: Juergen Gross <jgross@suse.com>
Tested-by: Juergen Gross <jgross@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

xen-scsiback: Convert to percpu_ida tag allocation

This patch converts xen-scsiback to use percpu_ida tag
pre-allocation for struct vscsibk_pend descriptor, in
order to avoid fast-path struct vscsibk_pend memory
allocations.

Note by default this is currently hardcoded to 128.

(Add wrapper for handling pending_req tag failure - Juergen)
(Drop left-over se_cmd memset in scsiback_cmd_exec - Juergen)

Acked-by: Juergen Gross <jgross@suse.com>
Tested-by: Juergen Gross <jgross@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

target: Convert demo-mode only drivers to target_alloc_session

This patch converts existing loopback, usb-gadget, and
xen-scsiback demo-mode only fabric drivers to use the
new target_alloc_session API caller.

This includes adding a new alloc_session callback for
fabric driver internal nexus pointer assignments.

(Fixes for early for-next nexus breakage - Dan Carpenter)

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Acked-by: Juergen Gross <jgross@suse.com>
Tested-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Tested-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

xen/scsiback: avoid warnings when adding multiple LUNs to a domain

When adding more than one LUN to a frontend a warning for a failed
assignment is issued in dom0 for each already existing LUN. Avoid this
warning by checking for a LUN already existing when existence is
allowed (scsiback_do_add_lun() called with try == 1).

As the LUN existence check is needed now for a third time, factor it
out into a function. This in turn leads to a more or less complete
rewrite of scsiback_del_translation_entry() which will now return a
proper error code in case of failure.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen/scsiback: correct frontend counting

When adding a new frontend to xen-scsiback don't decrement the number
of active frontends in case of no error. Doing so results in a failure
when trying to remove the xen-pvscsi nexus even if no domain is using
it.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen-scsiback: safely copy requests

The copy of the ring request was lacking a following barrier(),
potentially allowing the compiler to optimize the copy away.

Use RING_COPY_REQUEST() to ensure the request is copied to local
memory.

This is part of XSA155.

CC: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

target: use per-attribute show and store methods

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

xen-scsiback: Fix compile warning for 64-bit LUN

drivers/xen/xen-scsiback.c: In function ‘scsiback_add_translation_entry’:
drivers/xen/xen-scsiback.c:911:3: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘long long unsigned int’ [-Wformat]

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

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>

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>

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>

target: Convert se_portal_group->tpg_lun_list[] to RCU hlist

This patch converts the fixed size se_portal_group->tpg_lun_list[]
to use modern RCU with hlist_head in order to support an arbitary
number of se_lun ports per target endpoint.

It includes dropping core_tpg_alloc_lun() from core_dev_add_lun(),
and calling it directly from target_fabric_make_lun() to allocate
a new se_lun. And add a new target_fabric_port_release() configfs
item callback to invoke kfree_rcu() to release memory during
se_lun->lun_group shutdown.

Also now that se_node_acl->lun_entry_hlist is using RCU, convert
existing tpg_lun_lock to struct mutex so core_tpg_add_node_to_devs()
can perform RCU updater logic without releasing ->tpg_lun_mutex.

Also, drop core_tpg_clear_object_luns() and it's single consumer
in iscsi-target, which is duplicating TPG LUN shutdown logic and
is current code results in a NOP.

Finally, sbp-target and xen-scsiback fabric driver conversions are
included, which are required due to the non-standard way they use
->tpg_lun_hlist.

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

target: remove ->put_session method

The only instance of ->put_session is in qla2xxx, and was added by commit
aaf68b ("tcm_qla2xxx: Convert to TFO->put_session() usage") with the following
description:

This patch converts tcm_qla2xxx code to use an internal kref_put() for
se_session->sess_kref in order to ensure that qla_hw_data->hardware_lock
can be held while calling qlt_unreg_sess() for the final put.

But these day we're already holding the hardware lock over qlt_unreg_sess in
the ->close_session callback, so we're fine without this method.

(Re-add missing tcm_qla2xxx_release_session + drop put_session usage - nab)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

target: target_core_configfs.h is not needed in fabric drivers

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

target: Move task tag into struct se_cmd + support 64-bit tags

Simplify target core and target drivers by storing the task tag
a.k.a. command identifier inside struct se_cmd.

For several transports (e.g. SRP) tags are 64 bits wide.
Hence add support for 64-bit tags.

(Fix core_tmr_abort_task conversion spec warnings - nab)
(Fix up usb-gadget to use 16-bit tags - HCH + bart)

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>
Cc: <qla2xxx-upstream@qlogic.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

target: move transport ID handling to the core

Now that struct se_portal_group contains a protocol identifier field we can
take all the code to format an parse protocol identifiers in CDBs into common
code instead of leaving this to low-level drivers.

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

target: remove the get_fabric_proto_ident method

Now that we store the protocol identifier in the tpg structure we don't
need this method.

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

target: change core_tpg_register prototype

Remove the unneeded fabric_ptr argument, and change the type argument
to pass in a SPC protocol identifier.

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

target: move node ACL allocation to core code

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

target: refactor init/drop_nodeacl methods

By always allocating and adding, respectively removing and freeing
the se_node_acl structure in core code we can remove tons of repeated
code in the init_nodeacl and drop_nodeacl routines. Additionally
this now respects the get_default_queue_depth method in this code
path as well.

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

target: make the tpg_get_default_depth method optional

All fabric drivers except for iSCSI always return 1, so implement
that as default behavior.

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

xenbus_client: Extend interface to support multi-page ring

Originally Xen PV drivers only use single-page ring to pass along
information. This might limit the throughput between frontend and
backend.

The patch extends Xenbus driver to support multi-page ring, which in
general should improve throughput if ring is the bottleneck. Changes to
various frontend / backend to adapt to the new interface are also
included.

Affected Xen drivers:
* blkfront/back
* netfront/back
* pcifront/back
* scsifront/back
* vtpmfront

The interface is documented, as before, in xenbus_client.c.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

target: simplify the target template registration API

Instead of calling target_fabric_configfs_init() +
target_fabric_configfs_register() / target_fabric_configfs_deregister()
target_fabric_configfs_free() from every target driver, rewrite the API
so that we have simple register/unregister functions that operate on
a const operations vector.

This patch also fixes a memory leak in several target drivers. Several
target drivers namely called target_fabric_configfs_deregister()
without calling target_fabric_configfs_free().

A large part of this patch is based on earlier changes from
Bart Van Assche <bart.vanassche@sandisk.com>.

(v2: Add a new TF_CIT_SETUP_DRV macro so that the core configfs code
can declare attributes as either core only or for drivers)

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

loop/usb/vhost-scsi/xen-scsiback: Fix use of __transport_register_session

This patch changes loopback, usb-gadget, vhost-scsi and xen-scsiback
fabric code to invoke transport_register_session() instead of the
unprotected flavour, to ensure se_tpg->session_lock is taken when
adding new session list nodes to se_tpg->tpg_sess_list.

Note that since these four fabric drivers already hold their own
internal TPG mutexes when accessing se_tpg->tpg_sess_list, and
consist of a single se_session created through configfs attribute
access, no list corruption can currently occur.

So for correctness sake, go ahead and use the se_tpg->session_lock
protected version for these four fabric drivers.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

xen: scsiback: add LUN of restored domain

When a xen domain is being restored the LUN state of a pvscsi device
is "Connected" and not "Initialising" as in case of attaching a new
pvscsi LUN.

This must be taken into account when adding a new pvscsi device for
a domain as otherwise the pvscsi LUN won't be connected to the
SCSI target associated with it.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen-scsiback: define a pr_fmt macro with xen-pvscsi

Add the {xen-pvscsi: } prefix in pr_fmt and remove DPRINTK, then
replace all DPRINTK with pr_debug.

Also fixed up some comments just as eliminate redundant whitespace
and format the code.

These will make the code easier to read.

Signed-off-by: Tao Chen <boby.chen@huawei.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen-scsiback: mark pvscsi frontend request consumed only after last read

A request in the ring buffer mustn't be read after it has been marked
as consumed. Otherwise it might already have been reused by the
frontend without violating the ring protocol.

To avoid inconsistencies in the backend only work on a private copy
of the request. This will ensure a malicious guest not being able to
bypass consistency checks of the backend by modifying an active
request.

Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen/grant-table: add helpers for allocating pages

Add gnttab_alloc_pages() and gnttab_free_pages() to allocate/free pages
suitable to for granted maps.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

scsi: Conditionally compile in constants.c

Instead of having constants.c littered with ifdef statements we should
be moving dummy functions into the header and condintionally compile in
constants.c if selected. And update the Kconfig description to reflect
the actual size difference.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Tested-by: Robert Elliott <elliott@hp.com>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

scsi: remove MSG_*_TAG defines

For SPI drivers use the message definitions from scsi.h, and for target
drivers introduce a new TCM_*_TAG namespace.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com

scsi: use sdev as argument for sense code printing

We should be using the standard dev_printk() variants for
sense code printing.

[hch: remove __scsi_print_sense call in xen-scsiback, Acked by Juergen]
[hch: folded bracing fix from Dan Carpenter]
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

xen: remove DEFINE_XENBUS_DRIVER() macro

The DEFINE_XENBUS_DRIVER() macro looks a bit weird and causes sparse
errors.

Replace the uses with standard structure definitions instead. This is
similar to pci and usb device registration.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen-scsiback: clean up a type issue in scsiback_make_tpg()

This code was confusing because we had an unsigned long and then we
compared it to UINT_MAX and then we stored it in a u16. How many bytes
is this supposed to have: 2, 4 or 16???

I've made it a u16 throughout.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen-scsiback: Add Xen PV SCSI backend driver

Introduces the Xen pvSCSI backend. With pvSCSI it is possible for a
Xen domU to issue SCSI commands to a SCSI LUN assigned to that
domU. The SCSI commands are passed to the pvSCSI backend in a driver
domain (usually Dom0) which is owner of the physical device. This
allows e.g. to use SCSI tape drives in a Xen domU.

The code is taken from the pvSCSI implementation in Xen done by
Fujitsu based on Linux kernel 2.6.18.

Changes from the original version are:
- port to upstream kernel
- put all code in just one source file
- adapt to Linux style guide
- use target core infrastructure instead doing pure pass-through
- enable module unloading
- support SG-list in grant page(s)
- support task abort
- remove redundant struct backend
- allocate resources dynamically
- correct minor error in scsiback_fast_flush_area
- free allocated resources in case of error during I/O preparation
- remove CDB emulation, now handled by target core infrastructure

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>