Since commit 0278ccd9d5 "firewire: sbp2:
fix panic after rmmod with slow targets", the lifetime of an sbp2_target
instance does no longer extent past the return of sbp2_remove().
Therefore it is no longer necessary to call fw_unit_get/put() and
fw_device_get/put() in sbp2_probe/remove().
Furthermore, said commit also ensures that lu->work is not going to be
executed or requeued at a time when the sbp2_target is no longer in use.
Hence there is no need for sbp2_target reference counting for lu->work.
Other concurrent contexts:
- Processes which access the sysfs of the SCSI host device or of one
of its subdevices are safe because these interfaces are all removed
by scsi_remove_device/host() in sbp2_release_target().
- SBP-2 command block ORB transactions are finished when
scsi_remove_device() in sbp2_release_target() returns.
- SBP-2 management ORB transactions are finished when
cancel_delayed_work_sync(&lu->work) before sbp2_release_target()
returns.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
If firewire-sbp2 starts a login to a target that doesn't complete ORBs
in a timely manner (and has to retry the login), and the module is
removed before the operation times out, you end up with a null-pointer
dereference and a kernel panic.
[SR: This happens because sbp2_target_get/put() do not maintain
module references. scsi_device_get/put() do, but at occasions like
Chris describes one, nobody holds a reference to an SBP-2 sdev.]
This patch cancels pending work for each unit in sbp2_remove(), which
hopefully means there are no extra references around that prevent us
from unloading. This fixes my crash.
Signed-off-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
The struct sbp2_logical_unit.work items can all be executed in parallel
but are not reentrant. Furthermore, reconnect or re-login work must be
executed in a WQ_MEM_RECLAIM workqueue.
Hence replace the old single-threaded firewire-sbp2 workqueue by a
concurrency-managed but non-reentrant workqueue with rescuer.
firewire-core already maintains one, hence use this one.
In earlier versions of this change, I observed occasional failures of
parallel INQUIRY to an Initio INIC-2430 FireWire 800 to dual IDE bridge.
More testing indicates that parallel INQUIRY is not actually a problem,
but too quick successions of logout and login + INQUIRY, e.g. a quick
sequence of cable plugout and plugin, can result in failed INQUIRY.
This does not seem to be something that should or could be addressed by
serialization.
Another dual-LU device to which I currently have access to, an
OXUF924DSB FireWire 800 to dual SATA bridge with firmware from MacPower,
has been successfully tested with this too.
This change is beneficial to environments with two or more FireWire
storage devices, especially if they are located on the same bus.
Management tasks that should be performed as soon and as quickly as
possible, especially reconnect, are no longer held up by tasks on other
devices that may take a long time, especially login with INQUIRY and sd
or sr driver probe.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
We do not need slab allocations for ORB pointer write transactions
anymore in order to satisfy streaming DMA mapping constraints, thanks to
commit da28947e7e "firewire: ohci: avoid separate DMA mapping for
small AT payloads".
(Besides, the slab-allocated buffers that firewire-sbp2 used to provide
for 8-byte write requests were still not fully portable since they
shared a cacheline with unrelated CPU-accessed data.)
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
firewire-sbp2 already takes care for internal serialization where
required (ORB list accesses), and it does not use cmd->serial_number
internally. Hence it is safe to not grab the shost lock around
queuecommand.
While we are at housekeeping, drop a redundant struct member:
sbp2_command_orb.done is set once in a hot path and dereferenced once in
a hot path. We can as well dereference sbp2_command_orb.cmd->scsi_done
instead.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Now that firewire-core sets the local node's SPLIT_TIMEOUT to 2 seconds
per default, commit a481e97d3c is no
longer required.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Move the mid-layer's ->queuecommand() invocation from being locked
with the host lock to being unlocked to facilitate speeding up the
critical path for drivers who don't need this lock taken anyway.
The patch below presents a simple SCSI host lock push-down as an
equivalent transformation. No locking or other behavior should change
with this patch. All existing bugs and locking orders are preserved.
Additionally, add one parameter to queuecommand,
struct Scsi_Host *
and remove one parameter from queuecommand,
void (*done)(struct scsi_cmnd *)
Scsi_Host* is a convenient pointer that most host drivers need anyway,
and 'done' is redundant to struct scsi_cmnd->scsi_done.
Minimal code disturbance was attempted with this change. Most drivers
needed only two one-line modifications for their host lock push-down.
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix I/O stalls with some 4-bay RAID enclosures which are based on
OXUF936QSE:
- Onnto dataTale RSM4QO, old firmware (not anymore with current
firmware),
- inXtron Hydra Super-S LCM, old as well as current firmware
when used in RAID-5 mode, perhaps also in other RAID modes.
The stalls happen during heavy or moderate disk traffic in periods that
are a multiple of 5 minutes, roughly twice per hour. They are caused
by the target responding too late to an ORB_Pointer register write:
The target responds after Split_Timeout, hence firewire-core cancels
the transaction, and firewire-sbp2 fails the SCSI request. The SCSI
core retries the request, that fails again (and again), hence SCSI core
calls firewire-sbp2's abort handler (and even the Management_Agent
register write in the abort handler has the transaction timeout
problem).
During all that, the process which issued the I/O is stalled in I/O
wait state.
Meanwhile, the target actually acts on the first failed SCSI request:
It responds to the ORB_Pointer write later (seen in the kernel log as
"firewire_core: Unsolicited response") and also finishes the SCSI
request with proper status (seen in the kernel log as "firewire_sbp2:
status write for unknown orb").
So let's just ignore RCODE_CANCELLED in the transaction callback and
wait for the target to complete the ORB nevertheless. This requires
a small modification is sbp2_cancel_orbs(); it now needs to call
orb->callback() regardless whether fw_cancel_transaction() found the
transaction unfinished or finished.
A different solution is to increase Split_Timeout on the local node.
(Tested: 2000ms timeout; maybe 1000ms or something like that works too.
200ms is insufficient. Standard is 100ms.) However, I rather not do
this because any software on any node could change the Split_Timeout to
something unsuitable. Or such a large Split_Timeout may be undesirable
for other purposes.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
When an ORB was canceled (Command ORB i.e. SCSI request timed out, or
Management ORB timed out), or there was a send error in the initial
transaction, we missed to drop one of the ORB's references and thus
leaked memory.
Background:
In total, we hold 3 references to each Operation Request Block:
- 1 during sbp2_scsi_queuecommand() or sbp2_send_management_orb()
respectively,
- 1 for the duration of the write transaction to the ORB_Pointer or
Management_Agent register of the target,
- 1 for as long as the ORB stays within the lu->orb_list, until
the ORB is unlinked from the list and the orb->callback was
executed.
The latter one of these 3 references is finished
- normally by sbp2_status_write() when the target wrote status
for a pending ORB,
- or by sbp2_cancel_orbs() in case of an ORB time-out,
- or by complete_transaction() in case of a send error.
Of them, the latter two lacked the kref_put.
Add the missing kref_put()s. Add comments to the gets and puts of
references for transaction callbacks and ORB callbacks so that it is
easier to see what is supposed to happen.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Conflicts:
drivers/firewire/core-card.c
drivers/firewire/core-cdev.c
and forgotten #include <linux/time.h> in drivers/firewire/ohci.c
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
void (*fw_address_callback_t)(..., int speed, ...) is the speed that a
remote node chose to transmit a request to us. In case of split
transactions, firewire-core will transmit the response at that speed.
Upper layer drivers on the other hand (firewire-net, -sbp2, firedtv, and
userspace drivers) cannot do anything useful with that speed datum,
except log it for debug purposes. But data that is merely potentially
(not even actually) used for debug purposes does not belong into the API.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
In case of fw_card_bm_work()'s lock request, the present sizeof
expression is going to be wrong if somebody changes the fw_card's DMA
scratch buffer's size in the future.
In case of quadlet write requests, sizeof(u32) is just silly; it's 4.
In case of SBP-2 ORB pointer write requests, 8 is arguably quicker to
understand as the correct and only possible value than
sizeof(some_datum).
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: (23 commits)
firewire: ohci: extend initialization log message
firewire: ohci: fix IR/IT context mask mixup
firewire: ohci: add module parameter to activate quirk fixes
firewire: ohci: use an ID table for quirks detection
firewire: ohci: reorder struct fw_ohci for better cache efficiency
firewire: ohci: remove unused dualbuffer IR code
firewire: core: combine a bit of repeated code
firewire: core: change type of a data buffer
firewire: cdev: increment ABI version number
firewire: cdev: add more flexible cycle timer ioctl
firewire: core: rename an internal function
firewire: core: fix an information leak
firewire: core: increase stack size of config ROM reader
firewire: core: don't fail device creation in case of too large config ROM blocks
firewire: core: fix "giving up on config rom" with Panasonic AG-DV2500
firewire: remove incomplete Bus_Time CSR support
firewire: get_cycle_timer optimization and cleanup
firewire: ohci: enable cycle timer fix on ALi and NEC controllers
firewire: ohci: work around cycle timer bugs on VIA controllers
firewire: make PCI device id constant
...
The block layer calling convention is blk_queue_<limit name>.
blk_queue_max_sectors predates this practice, leading to some confusion.
Rename the function to appropriately reflect that its intended use is to
set max_hw_sectors.
Also introduce a temporary wrapper for backwards compability. This can
be removed after the merge window is closed.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Several config ROM related functions only peek at the ROM cache; mark
their arguments as const pointers. Ditto fw_device.config_rom and
fw_unit.directory, as the memory behind them is meant to be write-once.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
A few stylistic changes to unify some code patterns in the subsystem:
- The similar queue_delayed_work helpers fw_schedule_bm_work,
schedule_iso_resource, and sbp2_queue_work now have the same call
convention.
- Two conditional calls of schedule_iso_resource are factored into
another small helper.
- An sbp2_target_get helper is added as counterpart to
sbp2_target_put.
Object size of firewire-core is decreased a little bit, object size of
firewire-sbp2 remains unchanged.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
The Unit_Characteristics entry of an SBP-2 unit directory is not
mandatory as far as I can tell. If it is missing, we would probably
fail to log in into the target because firewire-sbp2 would not wait for
status after it sent the login request.
The fix moves the cleanup of tgt->mgt_orb_timeout into a place where it
is executed exactly once before login, rather than 0..n times depending
on the target's config ROM. With targets with one or more
Unit_Characteristics entries, the result is the same as before.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Per SBP-2 clause 5.3, a target shall store 8...32 bytes of status
information. Trailing zeros after the first 8 bytes don't need to be
stored, they are implicit. Fix the status write handler to clear all
unwritten status data.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
If a target writes invalid status (typically status of a command that
already timed out), firewire-sbp2 attempts to put away an ORB that
doesn't exist. https://bugzilla.redhat.com/show_bug.cgi?id=519772
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
ieee1394: sbp2: add support for disks >2 TB (and 16 bytes long CDBs)
firewire: sbp2: add support for disks >2 TB (and 16 bytes long CDBs)
firewire: core: do not DMA-map stack addresses
Increase the command ORB data structure to transport up to 16 bytes long
CDBs (instead of 12 bytes), and tell the SCSI mid layer about it. This
is notably necessary for READ CAPACITY(16) and friends, i.e. support of
large disks.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
firewire: core: use more outbound tlabels
firewire: core: don't update Broadcast_Channel if RFC 2734 conditions aren't met
firewire: core: prepare for non-core children of card devices
firewire: core: include linux/uaccess.h instead of asm/uaccess.h
firewire: add parent-of-unit accessor
firewire: rename source files
firewire: reorganize header files
firewire: clean up includes
firewire: ohci: access bus_seconds atomically
firewire: also use vendor ID in root directory for driver matches
firewire: share device ID table type with ieee1394
firewire: core: add sysfs attribute for easier udev rules
firewire: core: check for missing struct update at build time, not run time
firewire: core: improve check for local node
Retrieval of an fw_unit's parent is a common pattern in high-level code.
Wrap it up as device = fw_parent_device(unit).
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
The source files of firewire-core, firewire-ohci, firewire-sbp2, i.e.
"drivers/firewire/fw-*.c"
are renamed to
"drivers/firewire/core-*.c",
"drivers/firewire/ohci.c",
"drivers/firewire/sbp2.c".
The old fw- prefix was redundant to the directory name. The new core-
prefix distinguishes the files according to which driver they belong to.
This change comes a little late, but still before further firewire
drivers are added as anticipated RSN.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
