queuecommand() looked at the remote and local node IDs before it read
the bus generation. The corresponding race with sbp2_reconnect updating
these data was probably impossible to happen though because the current
code blocks the SCSI layer during reconnection. However, better safe
than sorry, especially if someone later improves the code to not block
the SCSI layer.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
1. We don't need to round the SBP-2 segment size limit down to a
multiple of 4 kB (0xffff -> 0xf000). It is only necessary to
ensure quadlet alignment (0xffff -> 0xfffc).
2. Use dma_set_max_seg_size() to tell the DMA mapping infrastructure
and the block IO layer about the restriction. This way we can
remove the size checks and segment splitting in the queuecommand
path.
This assumes that no other code in the firewire stack uses
dma_map_sg() with conflicting requirements. It furthermore assumes
that the controller device's platform actually allows us to set the
segment size to our liking. Assert the latter with a BUG_ON().
3. Also use blk_queue_max_segment_size() to tell the block IO layer
about it. It cannot know it because our scsi_add_host() does not
point to the FireWire controller's device.
Thanks to Grant Grundler and FUJITA Tomonori for advice.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Share code between fw_send_request + wait_for_completion callers.
Signed-off-by: Jay Fenlason <fenlason@redhat.com>
Addendum:
Removes an unnecessary struct and an ununsed retry loop.
Calls it fw_run_transaction() instead of fw_send_request_sync().
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Kristian Høgsberg <krh@redhat.com>
Add per-device dma_mapping_ops support for CONFIG_X86_64 as POWER
architecture does:
This enables us to cleanly fix the Calgary IOMMU issue that some devices
are not behind the IOMMU (http://lkml.org/lkml/2008/5/8/423).
I think that per-device dma_mapping_ops support would be also helpful for
KVM people to support PCI passthrough but Andi thinks that this makes it
difficult to support the PCI passthrough (see the above thread). So I
CC'ed this to KVM camp. Comments are appreciated.
A pointer to dma_mapping_ops to struct dev_archdata is added. If the
pointer is non NULL, DMA operations in asm/dma-mapping.h use it. If it's
NULL, the system-wide dma_ops pointer is used as before.
If it's useful for KVM people, I plan to implement a mechanism to register
a hook called when a new pci (or dma capable) device is created (it works
with hot plugging). It enables IOMMUs to set up an appropriate
dma_mapping_ops per device.
The major obstacle is that dma_mapping_error doesn't take a pointer to the
device unlike other DMA operations. So x86 can't have dma_mapping_ops per
device. Note all the POWER IOMMUs use the same dma_mapping_error function
so this is not a problem for POWER but x86 IOMMUs use different
dma_mapping_error functions.
The first patch adds the device argument to dma_mapping_error. The patch
is trivial but large since it touches lots of drivers and dma-mapping.h in
all the architecture.
This patch:
dma_mapping_error() doesn't take a pointer to the device unlike other DMA
operations. So we can't have dma_mapping_ops per device.
Note that POWER already has dma_mapping_ops per device but all the POWER
IOMMUs use the same dma_mapping_error function. x86 IOMMUs use device
argument.
[akpm@linux-foundation.org: fix sge]
[akpm@linux-foundation.org: fix svc_rdma]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix bnx2x]
[akpm@linux-foundation.org: fix s2io]
[akpm@linux-foundation.org: fix pasemi_mac]
[akpm@linux-foundation.org: fix sdhci]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix sparc]
[akpm@linux-foundation.org: fix ibmvscsi]
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This instructs sd_mod to send START STOP UNIT on suspend and resume,
and on driver unbinding or unloading (including when the system is shut
down).
We don't do this though if multiple initiators may log in to the target.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Tino Keitel <tino.keitel@gmx.de>
Reported by Tino Keitel: PL-3507 with firmware from Prolific does not
spin down the disk on START STOP UNIT with power condition = 0 and start
= 0. It does however work with power condition = 2 or 3.
Also found while investigating this: DViCO Momobay CX-1 and FX-3A (TI
TSB42AA9/A based) become unresponsive after START STOP UNIT with power
condition = 0 and start = 0. They stay responsive if power condition is
set when stopping the motor.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Tino Keitel <tino.keitel@gmx.de>
There is a small off-by-one bug in firewire-sbp2. This causes problems
when a device exports multiple LUN Directories. I found it when trying
to talk to a SONY DVD Jukebox.
Signed-off-by: Richard Sharpe <realrichardsharpe@gmail.com>
Acked-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (op. order, changelog)
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6:
[SCSI] aic94xx: fix section mismatch
[SCSI] u14-34f: Fix 32bit only problem
[SCSI] dpt_i2o: sysfs code
[SCSI] dpt_i2o: 64 bit support
[SCSI] dpt_i2o: move from virt_to_bus/bus_to_virt to dma_alloc_coherent
[SCSI] dpt_i2o: use standard __init / __exit code
[SCSI] megaraid_sas: fix suspend/resume sections
[SCSI] aacraid: Add Power Management support
[SCSI] aacraid: Fix jbod operations scan issues
[SCSI] aacraid: Fix warning about macro side-effects
[SCSI] add support for variable length extended commands
[SCSI] Let scsi_cmnd->cmnd use request->cmd buffer
[SCSI] bsg: add large command support
[SCSI] aacraid: Fix down_interruptible() to check the return value correctly
[SCSI] megaraid_sas; Update the Version and Changelog
[SCSI] ibmvscsi: Handle non SCSI error status
[SCSI] bug fix for free list handling
[SCSI] ipr: Rename ipr's state scsi host attribute to prevent collisions
[SCSI] megaraid_mbox: fix Dell CERC firmware problem
- struct scsi_cmnd had a 16 bytes command buffer of its own.
This is an unnecessary duplication and copy of request's
cmd. It is probably left overs from the time that scsi_cmnd
could function without a request attached. So clean that up.
- Once above is done, few places, apart from scsi-ml, needed
adjustments due to changing the data type of scsi_cmnd->cmnd.
- Lots of drivers still use MAX_COMMAND_SIZE. So I have left
that #define but equate it to BLK_MAX_CDB. The way I see it
and is reflected in the patch below is.
MAX_COMMAND_SIZE - means: The longest fixed-length (*) SCSI CDB
as per the SCSI standard and is not related
to the implementation.
BLK_MAX_CDB. - The allocated space at the request level
- I have audit all ISA drivers and made sure none use ->cmnd in a DMA
Operation. Same audit was done by Andi Kleen.
(*)fixed-length here means commands that their size can be determined
by their opcode and the CDB does not carry a length specifier, (unlike
the VARIABLE_LENGTH_CMD(0x7f) command). This is actually not exactly
true and the SCSI standard also defines extended commands and
vendor specific commands that can be bigger than 16 bytes. The kernel
will support these using the same infrastructure used for VARLEN CDB's.
So in effect MAX_COMMAND_SIZE means the maximum size command
scsi-ml supports without specifying a cmd_len by ULD's
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
When a device changes its configuration ROM, it announces this with a
bus reset. firewire-core has to check which node initiated a bus reset
and whether any unit directories went away or were added on this node.
Tested with an IOI FWB-IDE01AB which has its link-on bit set if bus
power is available but does not respond to ROM read requests if self
power is off. This implements
- recognition of the units if self power is switched on after fw-core
gave up the initial attempt to read the config ROM,
- shutdown of the units when self power is switched off.
Also tested with a second PC running Linux/ieee1394. When the eth1394
driver is inserted and removed on that node, fw-core now notices the
addition and removal of the IPv4 unit on the ieee1394 node.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Try to write dual-phase retry protocol limits to BUSY_TIMEOUT register.
- The dual-phase retry protocol is optional to implement, and if not
supported, writes to the dual-phase portion of the register will be
ignored. We try to write the original 1394-1995 default here.
- In the case of devices that are also SBP-3-compliant, all writes are
ignored, as the register is read-only, but contains single-phase retry of
15, which is what we're trying to set for all SBP-2 device anyway, so this
write attempt is safe and yields more consistent behavior for all devices.
See section 8.3.2.3.5 of the 1394-1995 spec, section 6.2 of the SBP-2 spec,
and section 6.4 of the SBP-3 spec for further details.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Write directly in big endian instead of byte-swapping after the fact.
This saves a few conversions, lets gcc use constant endianess
conversions where possible, and enables deeper endianess annotation.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Add wrappers for getting and putting a unit.
Remove some line breaks.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
The reference count of the unit dropped too low in an error path in
sbp2_probe. Fixed by moving the _get further up.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Fix I/O errors due to SYM13FW500's inability to handle larger request
sizes. Reported by Piergiorgio Sartor <piergiorgio.sartor@nexgo.de> in
https://bugzilla.redhat.com/show_bug.cgi?id=436879
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Per the SBP-2 specification, all SBP-2 target devices must have a BUSY_TIMEOUT
register. Per the 1394-1995 specification, the retry_limt portion of the
register should be set to 0x0 initially, and set on the target by a logged in
initiator (i.e., a Linux host w/firewire controller(s)).
Well, as it turns out, lots of devices these days have actually moved on to
starting to implement SBP-3 compliance, which says that retry_limit should
default to 0xf instead (yes, SBP-3 stomps directly on 1394-1995, oops).
Prior to this change, the firewire driver stack didn't touch retry_limit, and
any SBP-3 compliant device worked fine, while SBP-2 compliant ones were unable
to retransmit when the host returned an ack_busy_X, which resulted in stalled
out I/O, eventually causing the SCSI layer to give up and offline the device.
The simple fix is for us to set retry_limit to 0xf in the register for all
devices (which actually matches what the old ieee1394 stack did).
Prior to this change, a hard disk behind an SBP-2 Prolific PL-3507 bridge chip
would routinely encounter buffer I/O errors and wind up offlined by the SCSI
layer. With this change, I've encountered zero I/O failures moving tens of GB
of data around.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Patch "firewire: fw-sbp2: fix NULL pointer deref. in scsi_remove_device"
had the unintended effect that firewire-sbp2 could not be unloaded
anymore until all SBP-2 devices were unplugged.
We now fix the NULL pointer bug by reacquiring a reference to the sdev
instead of holding a reference to the sdev (and to the module) all the
time.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Jarod Wilson <jwilson@redhat.com>
Fix a kernel bug when unplugging an SBP-2 device after having its
scsi_device already removed via the "delete" sysfs attribute.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
While fw-sbp2 takes the necessary time to reconnect to a logical unit
after bus reset, the SCSI core keeps sending new commands. They are all
immediately completed with host busy status, and application clients or
filesystems will break quickly. The SCSI device might even be taken
offline: http://bugzilla.kernel.org/show_bug.cgi?id=9734
The only remedy seems to be to block the SCSI device until reconnect.
Alas the SCSI core has no useful API to block only one logical unit i.e.
the scsi_device, therefore we block the entire Scsi_Host. This
currently corresponds to an SBP-2 target. In case of targets with
multiple logical units, we need to satisfy the dependencies between
logical units by carefully tracking the blocking state of the target and
its units. We block all logical units of a target as soon as one of
them needs to be blocked, and keep them blocked until all of them are
ready to be unblocked.
Furthermore, as the history of the old sbp2 driver has shown, the
scsi_block_requests() API is a minefield with high potential of
deadlocks. We therefore take extra measures to keep logical units
unblocked during __scsi_add_device() and during shutdown.
This avoids I/O errors during reconnect in many but alas not in all
cases. There may still be errors after a re-login had to be performed.
Also, some bridges have been seen to cease fetching management ORBs if
I/O went on up until a bus reset. In these cases, all management ORBs
time out after mgt_orb_timeout. The old sbp2 driver is less vulnerable
or maybe not vulnerable to this, for as yet unknown reasons.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
fw-sbp2 is unable to reconnect while performing __scsi_add_device
because there is only a single workqueue thread context available for
both at the moment. This should be fixed eventually.
An actual failure of __scsi_add_device is easy to handle, but an
incomplete execution of __scsi_add_device with an sdev returned would
remain undetected and leave the SBP-2 target unusable.
Therefore we use a workaround: If there was a bus reset during
__scsi_add_device (i.e. during the SCSI probe), we remove the new sdev
immediately, log out, and attempt login and SCSI probe again.
Tested-by: Jarod Wilson <jwilson@redhat.com> (earlier version)
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
If fw-sbp2 was too late with requesting the reconnect, the target would
reject this. In this case, log out before attempting the reconnect.
Else several firmwares will deny the re-login because they somehow
didn't invalidate the old login.
Also, don't retry reconnects in this situation. The retries won't
succeed either.
These changes improve chances for successful re-login and shorten the
period during which the logical unit is inaccessible.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
When a reconnect failed but re-login succeeded, __scsi_add_device was
called again.
In those cases, __scsi_add_device succeeded and returned the pointer to
the existing scsi_device. fw-sbp2 then continued orderly, except that
it missed to call sbp2_cancel_orbs. SCSI core would call fw-sbp2's
eh_abort_handler eventually if there had been an outstanding command.
This patch avoids the needless lookups and temporary allocations in SCSI
core and I/O stall and timeout until eh_abort_handler hits.
Also, __scsi_add_device tolerating calls for devices which already exist
is undocumented behavior on which we shouldn't rely.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
for easier readable logs if more than one SBP-2 device is present.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Like the old sbp2 driver, wait for the write transaction to the
AGENT_RESET to complete before proceeding (after login, after reconnect,
or in SCSI error handling).
There is one occasion where AGENT_RESET is written to from atomic
context when getting DEAD status for a command ORB. There we still
continue without waiting for the transaction to complete because this
is more difficult to fix...
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Several different SBP-2 bridges accept a login early while the IDE
device is still powering up. They are therefore unable to respond to
SCSI INQUIRY immediately, and the SCSI core has to retry the INQUIRY.
One of these retries is typically successful, and all is well.
But in case of Momobay FX-3A, the INQUIRY retries tend to fail entirely.
This can usually be avoided by waiting a little while after login before
letting the SCSI core send the INQUIRY. The old sbp2 driver handles
this more gracefully for as yet unknown reasons (perhaps because it
waits for fetch agent resets to complete, unlike fw-sbp2 which quickly
proceeds after requesting the agent reset). Therefore the workaround is
not as much necessary for sbp2.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
If a device is being unplugged while fw-sbp2 had a login or reconnect on
schedule, it would take about half a minute to shut the fw_unit down:
Jan 27 18:34:54 stein firewire_sbp2: logged in to fw2.0 LUN 0000 (0 retries)
<unplug>
Jan 27 18:34:59 stein firewire_sbp2: sbp2_scsi_abort
Jan 27 18:34:59 stein scsi 25:0:0:0: Device offlined - not ready after error recovery
Jan 27 18:35:01 stein firewire_sbp2: orb reply timed out, rcode=0x11
Jan 27 18:35:06 stein firewire_sbp2: orb reply timed out, rcode=0x11
Jan 27 18:35:12 stein firewire_sbp2: orb reply timed out, rcode=0x11
Jan 27 18:35:17 stein firewire_sbp2: orb reply timed out, rcode=0x11
Jan 27 18:35:22 stein firewire_sbp2: orb reply timed out, rcode=0x11
Jan 27 18:35:27 stein firewire_sbp2: orb reply timed out, rcode=0x11
Jan 27 18:35:32 stein firewire_sbp2: orb reply timed out, rcode=0x11
Jan 27 18:35:32 stein firewire_sbp2: failed to login to fw2.0 LUN 0000
Jan 27 18:35:32 stein firewire_sbp2: released fw2.0
After this patch, typically only a few seconds spent in __scsi_add_device
remain:
Jan 27 19:05:50 stein firewire_sbp2: logged in to fw2.0 LUN 0000 (0 retries)
<unplug>
Jan 27 19:05:56 stein firewire_sbp2: sbp2_scsi_abort
Jan 27 19:05:56 stein scsi 33:0:0:0: Device offlined - not ready after error recovery
Jan 27 19:05:56 stein firewire_sbp2: released fw2.0
The benefit of this is less noise in the syslog. It furthermore avoids
a few wasted CPU cycles and needlessly prolonged lifetime of a few
driver objects.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
This fixes a "can't recognize device" kind of bug.
If the SCSI INQUIRY failed and hence __scsi_add_device failed due to a
bus reset, we tried a logout and then waited for the already scheduled
login work to happen. So far so good, but the generation used for the
logout was outdated, hence the logout never reached the target. The
target might therefore deny the subsequent relogin attempt, which would
also leave the target inaccessible.
Therefore fetch a fresh device->generation for the logout. Use memory
barriers to prevent our plan being foiled by compiler or hardware
optimizations.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
To be more compliant with section 7.4.8 of the SBP-2 specification,
use the mgt_ORB_timeout specified in the SBP-2 device's config rom
for login ORB attempts (though with some sanity checks). A happy
side-effect is that certain device and controller combinations that
sometimes take more than 20 seconds to get synced up (like my laptop
with just about any SBP-2 device) now function more reliably.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (silenced sparse)
Increase (and rename) the login orb reply timeout value to 20s
to match that of the old firewire stack. 2s simply didn't give
many devices enough time to spin up and reply.
Fixes inability to recognize some devices.
Failure mode was "orb reply timed out"/"failed to login".
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (style, comments, changelog)
fw_device.node_id and fw_device.generation are accessed without mutexes.
We have to ensure that all readers will get to see node_id updates
before generation updates.
Fixes an inability to recognize devices after "giving up on config rom",
https://bugzilla.redhat.com/show_bug.cgi?id=429950
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Reviewed by Nick Piggin <nickpiggin@yahoo.com.au>.
Verified to fix 'giving up on config rom' issues on multiple system and
drive combinations that were previously affected.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
There was a small window where a login or reconnect job could use an
already updated card generation with an outdated node ID. We have to
use the fw_device.generation here, not the fw_card.generation, because
the generation must never be newer than the node ID when we emit a
transaction. This cannot be guaranteed with fw_card.generation.
Furthermore, the target's and initiator's node IDs can be obtained from
fw_device and fw_card. Dereferencing their underlying topology objects
is not necessary.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Verified in concert with subsequent memory barriers patch to fix 'giving
up on config rom' issues on multiple system and drive combinations that
were previously affected.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Ask the target to grant 4 seconds instead of the standard and minimum of
1 second window after bus reset for reconnection. This accelerates
reconnection if there are more than one targets on the bus: If a login
and inquiry to one target blocks the fw-sbp2 workqueue for more than 1s
after bus reset, we now still can reconnect to the other target.
Before that, fw-sbp2's reconnect attempts would be rejected with "error
status: 0:9" (function rejected), and fw-sbp2 would finally re-login.
All those futile reconnect attemps cost extra time until the target
which needs re-login is ready for I/O again.
The reconnect timeout field in the login ORB doesn't have to be honored
by the target though. I found that we could get up to
- allegedly 32768s from an old OXFW911 firmware
- 256s from LSI bridges
- 4s from OXUF922 and OXFW912 bridges,
- 2s from TI bridges,
- only the standard 1s from Initio and Prolific bridges and from
Apple OpenFirmware in target mode.
We just try to get 4 seconds which already covers the case of a few
HDDs on the same bus quite nicely.
A minor drawback occurs in the following (rare and impractical) border
case:
- two initiators are there, initiator 1 holds an exclusive login to
a target,
- initiator 1 goes off the bus,
- target refuses login attempts from initiator 2 until reconnect_hold
seconds after bus reset.
An alternative approach to the issue at hand would be to parallelize
fw-sbp2's reconnect and login work.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Jarod Wilson <jwilson@redhat.com>
Don't attempt to send a logout ORB if the target was already unplugged
or had its link switched off. If two targets are attached, this
enhances the chance to quickly reconnect to the remaining target when
one target is plugged out.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Jarod Wilson <jwilson@redhat.com>
SBP2_MAX_SECTORS is nowhere used in fw-sbp2.
It merely got copied over from sbp2 where it played a role in the past.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This patch relaxes the default SCSI DMA alignment from 512 bytes to 4
bytes. I remember from previous discussions that usb and firewire have
sector size alignment requirements, so I upped their alignments in the
respective slave allocs.
The reason for doing this is so that we don't get such a huge amount of
copy overhead in bio_copy_user() for udev. (basically all inquiries it
issues can now be directly mapped).
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Since patch "fw-sbp2: use an own workqueue (fix system responsiveness)"
increased parallelism between fw-sbp2 and fw-core, it was possible that
fw-sbp2 didn't release the SCSI device when the FireWire device was
disconnected.
This happened if sbp2_update() ran during sbp2_login(), because a bus
reset occurred during sbp2_login(). The sbp2_login() work would [try
to] reschedule itself because it failed due to the bus reset, and it
would _not_ drop its reference on the target. However, sbp2_update()
would schedule sbp2_login() too before sbp2_login() rescheduled itself
and hence sbp2_update() would take an additional reference. And then
we would have one reference too many.
The fix is to _always_ drop the reference when leaving the sbp2_login()
work. If the sbp2_login() work reschedules itself, it takes a
reference, but only if it wasn't already rescheduled by sbp2_update().
Ditto in the sbp2_reconnect() work.
The resulting code is actually simpler than before: We _always_ take
a reference when successfully scheduling work. And we _always_ drop
a reference when leaving a workqueue job. No exceptions.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Firewire-sbp2 did very uncooperative things in the kernel's shared
workqueue: Sleeping until reception of management status from the
target for up to 2 seconds, and performing SCSI inquiry and all of the
setup of SCSI command set drivers via scsi_add_device. If there were
transient or permanent error conditions, this caused long blockage of
the kernel's events process, noticeable e.g. by blocked keyboard input.
We now allocate a workqueue process exclusive to fw-sbp2. As a side
effect, this also increases parallelism of fw-sbp2's login and reconnect
work versus fw-core's device discovery and device update work which is
performed in the shared workqueue.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
On rare occasions, the ability to set one of the workaround flags at
runtime may save the day.
People who experience I/O errors with firewire-sbp2 while the old sbp2
driver worked for them should try workarounds=1 and report to the devel
mailinglist whether that improves things. Firewire-sbp2 defaults to the
SCSI stack's maximum transfer size per command, while sbp2 limits them
to 128 kBytes. Flag 1 accomplishes just that.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
