scsi: core: Replace scsi_target_block() with scsi_block_targets()

All callers (fc_remote_port_delete(), __iscsi_block_session(),
__srp_start_tl_fail_timers(), srp_reconnect_rport(), snic_tgt_del()) pass
parent devices of scsi_target devices to scsi_target_block().

Rename the function to scsi_block_targets(), and simplify it by assuming
that it is always passed a parent device. Also, have callers pass the
Scsi_Host pointer to scsi_block_targets(), as every caller has this pointer
readily available.

Suggested-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Link: https://lore.kernel.org/r/20230614103616.31857-7-mwilck@suse.com
Cc: Karan Tilak Kumar <kartilak@cisco.com>
Cc: Sesidhar Baddela <sebaddel@cisco.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: core: Change the return type of .eh_timed_out()

Commit 6600593cbd93 ("block: rename BLK_EH_NOT_HANDLED to BLK_EH_DONE")
made it impossible for .eh_timed_out() implementations to call
scsi_done() without causing a crash.

Restore support for SCSI timeout handlers to call scsi_done() as follows:

* Change all .eh_timed_out() handlers as follows:

- Change the return type into enum scsi_timeout_action.
- Change BLK_EH_RESET_TIMER into SCSI_EH_RESET_TIMER.
- Change BLK_EH_DONE into SCSI_EH_NOT_HANDLED.

* In scsi_timeout(), convert the SCSI_EH_* values into BLK_EH_* values.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221018202958.1902564-3-bvanassche@acm.org
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: scsi_transport_srp: Don't block target in SRP_PORT_LOST state

rport_dev_loss_timedout() sets the rport state to SRP_PORT_LOST and the
SCSI target state to SDEV_TRANSPORT_OFFLINE. If this races with
srp_reconnect_work(), a warning is printed:

Mar 27 18:48:07 ictm1604s01h4 kernel: dev_loss_tmo expired for SRP port-18:1 / host18.
Mar 27 18:48:07 ictm1604s01h4 kernel: ------------[ cut here ]------------
Mar 27 18:48:07 ictm1604s01h4 kernel: scsi_internal_device_block(18:0:0:100) failed: ret = -22
Mar 27 18:48:07 ictm1604s01h4 kernel: Call Trace:
Mar 27 18:48:07 ictm1604s01h4 kernel: ? scsi_target_unblock+0x50/0x50 [scsi_mod]
Mar 27 18:48:07 ictm1604s01h4 kernel: starget_for_each_device+0x80/0xb0 [scsi_mod]
Mar 27 18:48:07 ictm1604s01h4 kernel: target_block+0x24/0x30 [scsi_mod]
Mar 27 18:48:07 ictm1604s01h4 kernel: device_for_each_child+0x57/0x90
Mar 27 18:48:07 ictm1604s01h4 kernel: srp_reconnect_rport+0xe4/0x230 [scsi_transport_srp]
Mar 27 18:48:07 ictm1604s01h4 kernel: srp_reconnect_work+0x40/0xc0 [scsi_transport_srp]

Avoid this by not trying to block targets for rports in SRP_PORT_LOST
state.

Link: https://lore.kernel.org/r/20210401091105.8046-1-mwilck@suse.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: scsi_transport_srp: Don't block target in failfast state

If the port is in SRP_RPORT_FAIL_FAST state when srp_reconnect_rport() is
entered, a transition to SDEV_BLOCK would be illegal, and a kernel WARNING
would be triggered. Skip scsi_target_block() in this case.

Link: https://lore.kernel.org/r/20210111142541.21534-1-mwilck@suse.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: scsi_transport_srp: Sanitize scsi_target_block/unblock sequences

The SCSI midlayer does not allow state transitions from SDEV_BLOCK to
SDEV_BLOCK so calling scsi_target_block() from __rport_fast_io_fail() is
wrong as the port is already blocked. Similarly, we don't need to call
scsi_target_unblock() afterwards as the function has already done this.

Link: https://lore.kernel.org/r/20200728134833.42547-1-hare@suse.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 502

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation version 2 of the license this program
is distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 51 franklin st fifth floor boston ma 02110
1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081207.195075312@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scsi: scsi_transport_srp: switch to SPDX tags

Use the the GPLv2+ SPDX tag instead of verbose boilerplate text.

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

block: rename BLK_EH_NOT_HANDLED to BLK_EH_DONE

The BLK_EH_NOT_HANDLED implies nothing happen, but very often that
is not what is happening - instead the driver already completed the
command. Fix the symbolic name to reflect that a little better.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

scsi: scsi_transport_srp: Fix shost to rport translation

Since an SRP remote port is attached as a child to shost->shost_gendev
and as the only child, the translation from the shost pointer into an
rport pointer must happen by looking up the shost child that is an
rport. This patch fixes the following KASAN complaint:

BUG: KASAN: slab-out-of-bounds in srp_timed_out+0x57/0x110 [scsi_transport_srp]
Read of size 4 at addr ffff880035d3fcc0 by task kworker/1:0H/19

CPU: 1 PID: 19 Comm: kworker/1:0H Not tainted 4.16.0-rc3-dbg+ #1
Workqueue: kblockd blk_mq_timeout_work
Call Trace:
dump_stack+0x85/0xc7
print_address_description+0x65/0x270
kasan_report+0x231/0x350
srp_timed_out+0x57/0x110 [scsi_transport_srp]
scsi_times_out+0xc7/0x3f0 [scsi_mod]
blk_mq_terminate_expired+0xc2/0x140
bt_iter+0xbc/0xd0
blk_mq_queue_tag_busy_iter+0x1c7/0x350
blk_mq_timeout_work+0x325/0x3f0
process_one_work+0x441/0xa50
worker_thread+0x76/0x6c0
kthread+0x1b2/0x1d0
ret_from_fork+0x24/0x30

Fixes: e68ca75200fe ("scsi_transport_srp: Reduce failover time")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Revert "scsi: make 'state' device attribute pollable"

This reverts commit 8a97712e5314aefe16b3ffb4583a34deaa49de04.

This commit added a call to sysfs_notify() from within
scsi_device_set_state(), which in turn turns out to make libata very
unhappy, because ata_eh_detach_dev() does

spin_lock_irqsave(ap->lock, flags);
..
if (ata_scsi_offline_dev(dev)) {
dev->flags |= ATA_DFLAG_DETACHED;
ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
}

and ata_scsi_offline_dev() then does that scsi_device_set_state() to set
it offline.

So now we called sysfs_notify() from within a spinlocked region, which
really doesn't work. The 0day robot reported this as:

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238

because sysfs_notify() ends up calling kernfs_find_and_get_ns() which
then does mutex_lock(&kernfs_mutex)..

The pollability of the device state isn't critical, so revert this all
for now, and maybe we'll do it differently in the future.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scsi: scsi_transport_srp: Suppress a W=1 compiler warning

Avoid that the following compiler warning is reported when building
with W=1:

drivers/scsi/scsi_transport_srp.c:92:19: warning: comparison is always false due to limited range of data type [-Wtype-limits]

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: make 'state' device attribute pollable

While the 'state' attribute can (and will) change occasionally,
calling 'poll()' or 'select()' on it fails as sysfs is never
notified that the state has changed.
With this patch calling 'poll()' or 'select()' will work
properly.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: Protect SCSI device state changes with a mutex

Serializing SCSI device state changes avoids that two state changes can
occur concurrently, e.g. the state changes in scsi_target_block() and
__scsi_remove_device(). This serialization is essential to make patch
"Make __scsi_remove_device go straight from BLOCKED to DEL" work
reliably.

Enable this mechanism for all scsi_target_*block() callers but not for
the scsi_internal_device_unblock() calls from the mpt3sas driver because
that driver can call scsi_internal_device_unblock() from atomic context.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: remove tsk_mgmt_response and it_nexus_response transport methods

They are never called and just dispatch to methods of the same names in
the FC and SRP transport classes that are never implemented.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: remove eh_timed_out methods in the transport template

Instead define the timeout behavior purely based on the host_template
eh_timed_out method and wire up the existing transport implementations
in the host templates. This also clears up the confusion that the
transport template method overrides the host template one, so some
drivers have to re-override the transport template one.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: srp_transport: Move queuecommand() wait code to SCSI core

Additionally, rename srp_wait_for_queuecommand() into
scsi_wait_for_queuecommand() and add a comment about the queuecommand()
call from scsi_send_eh_cmnd().

Note: this patch changes scsi_internal_device_block from a function that
did not sleep into a function that may sleep. This is fine for all
callers of this function:

* scsi_internal_device_block() is called from the mpt3sas device while
that driver holds the ioc->dm_cmds.mutex. This means that the mpt3sas
driver calls this function from thread context.
* scsi_target_block() is called by __iscsi_block_session() from
kernel thread context and with IRQs enabled.
* The SRP transport code also calls scsi_target_block() from kernel
thread context while sleeping is allowed.
* The snic driver also calls scsi_target_block() from a context from
which sleeping is allowed. The scsi_target_block() call namely occurs
immediately after a scsi_flush_work() call.

[mkp: s/shost/sdev/]

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: James Bottomley <jejb@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Doug Ledford <dledford@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: replace custom approach to hexdump small buffers

In kernel we have defined specifier (%*ph[C]) to dump small buffers in a
hex format. Replace custom approach by a generic one.

Cc: Jon Mason <jonmason@broadcom.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

IB/srp: Avoid using uninitialized variable

We might return res which is not initialized. Also
reduce code duplication by exporting srp_parse_tmo so
srp_tmo_set can reuse it.

Detected by Coverity.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jenny Falkovich <jennyf@mellanox.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

scsi_transport_srp: Reduce failover time

Unlike FC, there is no risk that SCSI devices will be offlined
by the SCSI error handler if the SCSI error handler is started
while a reconnect attempt is ongoing. Hence report timeout errors
as soon as possible if a higher software layer (e.g. multipathd)
needs to be informed about a timeout. It is assumed that if both
fast_io_fail_tmo < 0 and rport->dev_loss_tmo < 0 that this means
that there is no need to report timeouts quickly.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: James Bottomley <JBottomley@Odin.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

scsi_transport_srp: Fix a race condition

Avoid that srp_terminate_io() can get invoked while srp_queuecommand()
is in progress. This patch avoids that an I/O timeout can trigger the
following kernel warning:

WARNING: at drivers/infiniband/ulp/srp/ib_srp.c:1447 srp_terminate_io+0xef/0x100 [ib_srp]()
Call Trace:
[<ffffffff814c65a2>] dump_stack+0x4e/0x68
[<ffffffff81051f71>] warn_slowpath_common+0x81/0xa0
[<ffffffff8105204a>] warn_slowpath_null+0x1a/0x20
[<ffffffffa075f51f>] srp_terminate_io+0xef/0x100 [ib_srp]
[<ffffffffa07495da>] __rport_fail_io_fast+0xba/0xc0 [scsi_transport_srp]
[<ffffffffa0749a90>] rport_fast_io_fail_timedout+0xe0/0xf0 [scsi_transport_srp]
[<ffffffff8106e09b>] process_one_work+0x1db/0x780
[<ffffffff8106e75b>] worker_thread+0x11b/0x450
[<ffffffff81073c64>] kthread+0xe4/0x100
[<ffffffff814cf26c>] ret_from_fork+0x7c/0xb0

See also patch "scsi_transport_srp: Add transport layer error
handling" (commit ID 29c17324803c).

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: James Bottomley <JBottomley@Odin.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.13
Signed-off-by: Doug Ledford <dledford@redhat.com>

scsi_transport_srp: Introduce srp_wait_for_queuecommand()

Introduce the helper function srp_wait_for_queuecommand().
Move the definition of scsi_request_fn_active(). Add a comment
above srp_wait_for_queuecommand() that support for scsi-mq needs
to be added.

This patch does not change any functionality. A second call to
srp_wait_for_queuecommand() will be introduced in the next patch.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: James Bottomley <JBottomley@Odin.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.13
Signed-off-by: Doug Ledford <dledford@redhat.com>

scsi_transport_srp: Fix fast_io_fail_tmo=dev_loss_tmo=off behavior

If scsi_remove_host() is called while an rport is in the blocked state
then scsi_remove_host() will only finish if the rport is unblocked
from inside a timer function. Make sure that an rport only enters the
blocked state if a timer will be started that will unblock it. This
avoids that unloading the ib_srp kernel module after having
disconnected the initiator from the target system results in a
deadlock if both the fast_io_fail_tmo and dev_loss_tmo parameters have
been set to "off".

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: David Dillow <dave@thedillows.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

tgt: removal

Now that the ibmvstgt driver as the only user of scsi_tgt is gone, the
scsi_tgt kernel module, the CONFIG_SCSI_TGT, CONFIG_SCSI_SRP_TGT_ATTRS and
CONFIG_SCSI_FC_TGT_ATTRS kbuild variable, the scsi_host_template
transfer_response method are no longer needed.

[hch: minor updates to the current tree, changelog update]

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>

scsi_transport_srp: Fix two kernel-doc warnings

This patch fixes the following two kernel-doc warnings:

Warning(drivers/scsi/scsi_transport_srp.c:819): No description found for parameter 'rport'
Warning(include/scsi/scsi_transport_srp.h:75): Excess struct/union/enum/typedef member 'deleted' description in 'srp_rport'

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reported-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Sebastian Riemer <sebastian.riemer@profitbricks.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

scsi_transport_srp: Fix kernel-doc warnings

The following command has been used to verify that the kernel-doc
tool no longer complains about undocumented fields:

scripts/kernel-doc -html drivers/scsi/scsi_transport_srp.c \
include/scsi/scsi_transport_srp.h >srp-transport-doc.html

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Sebastian Riemer <sebastian.riemer@profitbricks.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

scsi_transport_srp: Fix a race condition

The rport timers must be stopped before the SRP initiator destroys the
resources associated with the SCSI host. This is necessary because
otherwise the callback functions invoked from the SRP transport layer
could trigger a use-after-free. Stopping the rport timers before
invoking scsi_remove_host() can trigger long delays in the SCSI error
handler if a transport layer failure occurs while scsi_remove_host()
is in progress. Hence move the code for stopping the rport timers from
srp_rport_release() into a new function and invoke that function after
scsi_remove_host() has finished. This patch fixes the following
sporadic kernel crash:

kernel BUG at include/asm-generic/dma-mapping-common.h:64!
invalid opcode: 0000 [#1] SMP
RIP: 0010:[<ffffffffa03b20b1>] [<ffffffffa03b20b1>] srp_unmap_data+0x121/0x130 [ib_srp]
Call Trace:
[<ffffffffa03b20fc>] srp_free_req+0x3c/0x80 [ib_srp]
[<ffffffffa03b2188>] srp_finish_req+0x48/0x70 [ib_srp]
[<ffffffffa03b21fb>] srp_terminate_io+0x4b/0x60 [ib_srp]
[<ffffffffa03a6fb5>] __rport_fail_io_fast+0x75/0x80 [scsi_transport_srp]
[<ffffffffa03a7438>] rport_fast_io_fail_timedout+0x88/0xc0 [scsi_transport_srp]
[<ffffffff8108b370>] worker_thread+0x170/0x2a0
[<ffffffff81090876>] kthread+0x96/0xa0
[<ffffffff8100c0ca>] child_rip+0xa/0x20

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

scsi_transport_srp: Block rport upon TL error even with fast_io_fail_tmo = off

The current behavior of the SRP transport layer when a transport layer
error is encountered is to block SCSI command processing only if
fast_io_fail_tmo != off. The current behavior of the FC transport
layer when a transport layer error is encountered is to block SCSI
command processing no matter which value fast_io_fail_tmo has been set
to. Make the behavior of the SRP transport layer consistent with that
of the FC transport layer to avoid confusion.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

scsi_transport_srp: Add periodic reconnect support

Add support for periodically reconnecting to an SRP target until
the dev_loss timer expires. After the tenth reconnection attempt,
gradually slow down subsequent reconnect attempts.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>

scsi_transport_srp: Add transport layer error handling

Add the necessary functions in the SRP transport module to allow an
SRP initiator driver to implement transport layer error handling
similar to the functionality already provided by the FC transport
layer. This includes:

- Support for implementing fast_io_fail_tmo, the time that should
elapse after having detected a transport layer problem and
before failing I/O.
- Support for implementing dev_loss_tmo, the time that should
elapse after having detected a transport layer problem and
before removing a remote port.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/srp: Keep rport as long as the IB transport layer

Keep the rport data structure around after srp_remove_host() has
finished until cleanup of the IB transport layer has finished
completely. This is necessary because later patches use the rport
pointer inside the queuecommand callback. Without this patch
accessing the rport from inside a queuecommand callback is racy
because srp_remove_host() must be invoked before scsi_remove_host()
and because the queuecommand callback could get invoked after
srp_remove_host() has finished. In other words, without this patch
the queuecommand callback can get invoked after the rport data
structure has been freed.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/srp: Allow SRP disconnect through sysfs

Make it possible to disconnect the IB RC connection used by the SRP
protocol to communicate with a target.

Have the SRP transport layer create a sysfs "delete" attribute for
initiator drivers that support this functionality.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

srp_transport: Simplify attribute initialization code

Eliminate the private_rport_attrs[] array and the SETUP_*() macros
used to set up that array since the information in that array
duplicates the information in the static device attributes. Also,
verify whether SRP_RPORT_ATTRS is large enough since it is easy to
forget to update that macro when adding new attributes.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Robert Jennings <rcj@linux.vnet.ibm.com>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>

srp_transport: Fix attribute registration

Register transport attributes after the attribute array has been set
up instead of before. The current code can trigger a race condition
because the code reading the attribute array can run on another thread
than the code that initialized that array. Make sure that any code
reading the attribute array will see all values written into that
array.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Robert Jennings <rcj@linux.vnet.ibm.com>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>

[SCSI] struct device - replace bus_id with dev_name(), dev_set_name()

[jejb: limit ioctl to returning 20 characters to avoid overrun
on long device names and add a few more conversions]
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

SCSI: convert struct class_device to struct device

It's big, but there doesn't seem to be a way to split it up smaller...

Signed-off-by: Tony Jones <tonyj@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[SCSI] docbook and kernel-doc updates

- Change title to remove "Mid-Layer" since the doc is about all of the
SCSI layers.
- Use "SCSI" instead of "scsi" in docbook text.
- Use "*/" to end kernel-doc notation blocks.
- A few other minor typo fixes.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] Add Documentation and integrate into docbook build

Add Documentation/DocBook/scsi_midlayer.tmpl, add to Makefile, and update
lots of kerneldoc comments in drivers/scsi/*.

Updated with comments from Stefan Richter, Stephen M. Cameron,
James Bottomley and Randy Dunlap.

Signed-off-by: Rob Landley <rob@landley.net>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] SRP transport: only remove our own entries

The SCSI SRP transport class currently iterates over all children
devices of the host that is being removed in srp_remove_host(). However,
not all of those children were created by the SRP transport, and
removing them will cause corruption and an oops when their creator tries
to remove them.

Signed-off-by: David Dillow <dillowda@ornl.gov>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] srp_transport: convert to use supported_mode attribute

srp transport works for target drivers without supported_mode
attribute but it would be better to use it explicitly.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

[SCSI] scsi_transport_srp: remove tgt dependencies

it's better to remove tgt dependencies in srp transport class since
most people want only initiator support.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

[SCSI] tgt: move tsk_mgmt_response callback to transport class

This moves tsk_mgmt_response callback in struct scsi_host_template to
struct scsi_transport_template since struct scsi_transport_template is
more suitable for the task management stuff.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

[SCSI] srp_transport: add target driver support

This adds minimum target driver support:

- srp_rport_{add,del} calls scsi_tgt_it_nexus_{create,destroy} for
target drivers.

- add a callback to notify target drivers of the nexus operation
results to srp_function_template.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

[SCSI] transport_srp: add rport roles attribute

This adds a 'roles' attribute to rport like transport_fc. The role can
be initiator or target. That is, the initiator driver creates target
remote ports and the target driver creates initiator remote ports.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

[SCSI] add srp transport class

This adds srp transport class that works with ib_srp and ibmvscsi.

It creates only /sys/class/{srp_host,srp_remote_ports} and
srp_remote_ports has only "port_id" attribute.

viola:/sys/class/srp_remote_ports/port-0:1# ls
device port_id subsystem uevent
viola:/sys/class/srp_remote_ports/port-0:1# cat port_id
4c:49:4e:55:58:20:56:49:4f:00:00:00:00:00:00:00

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>