Use ATA_ID_CFA_* constants for CFA specific identify data words 162 and 163.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
WDC WD1600JS-62MHB5 successfully hits the window between ATA/ATAPI-7
and Serial ATA II standards and reports 3c/c3 signature which now is
assigned to SEMB. Make ata_dev_classify() report ATA_DEV_SEMB on the
sig and let ata_dev_read_id() work around it by trying IDENTIFY once.
This fixes bko#11579.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Haun <drhaun88@gmail.com>
Reported-by: Lars Wirzenius <liw@liw.fi>
Reported-by: Juan Manuel <jmcarranza@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Also remove the now-useless debug printouts which are supposed to
tell us when the scan starts and ends.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Make libata more robust when parsing the multi_count
field from a drive's identify data. This prevents us from
attempting to use dubious multi_count values ad infinitum.
Reset dev->multi_count to zero and reprobe it each time
through this routine, as it can change on device reset.
Also ensure that the reported "maximum" value is valid
and is a power of two, and that the reported "count" value
is valid and also a power of two. And that the "count"
value is not greater than the "maximum" value.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Hanno Böck reported a problem where an old Conner CP30254 240MB hard drive
was reported as 1.1TB in capacity by libata:
http://lkml.org/lkml/2009/2/13/134
This was caused by libata trusting the drive's reported current capacity in
sectors in identify words 57 and 58 if the drive does not support LBA and the
current CHS translation values appear valid. Unfortunately it seems older
ATA specs were vague about what this field should contain and a number of drives
used values with wrong byte order or that were totally bogus. There's no
unique information that it conveys and so we can just calculate the number
of sectors from the reported current CHS values.
While we're at it, clean up this function to use named constants for the
identify word values.
Signed-off-by: Robert Hancock <hancockrwd@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
libata passes the returned value of dma_map_sg() to
dma_unmap_sg(),which is the misuse of dma_unmap_sg().
DMA-mapping.txt says:
To unmap a scatterlist, just call:
pci_unmap_sg(pdev, sglist, nents, direction);
Again, make sure DMA activity has already finished.
PLEASE NOTE: The 'nents' argument to the pci_unmap_sg call must be
the _same_ one you passed into the pci_map_sg call,
it should _NOT_ be the 'count' value _returned_ from the
pci_map_sg call.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
3Gbps is often much more prone to transmission failures. It's usually
okay to let EH handle speed down after transmission failures but some
WD My Book drives completely shutdown after certain transmission
failures and after it only power cycling can revive them. Combined
with the fact that external drives often end up with cable assembly
which is longer than usual and more likely to have intervening gender,
this makes these drives very likely to shutdown under certain
configurations virtually rendering them unusable.
This patch implements HOARKGE_1_5_GBPS and applies it to WD My Book
such that 1.5Gbps is forced once the device is identified.
Please take a look at the following bz for related reports.
http://bugzilla.kernel.org/show_bug.cgi?id=9913
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Add @spd_limit to sata_down_spd_limit() so that the caller can specify
the SPD limit it wants. This parameter doesn't get in the way even
when it's too low. The closest possible limit is applied.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
dev->ering used to be cleared together with the rest of ata_device in
ata_dev_init() which is called whenever a probing event occurs.
dev->ering is about to be used to track probing failures so it needs
to remain persistent over multiple porbing events. This patch
achieves this by doing the following.
* Instead of CLEAR_OFFSET, define CLEAR_BEGIN and CLEAR_END and only
clear between BEGIN and END. ering is moved after END. The split
of persistent area is to allow hotter items remain at the head.
* ering is explicitly cleared on ata_dev_disable() and when device
attach succeeds. So, ering is persistent throug a device's life
time (unless explicitly cleared of course) and also through periods
inbetween disablement of an attached device and successful detection
of the next one.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
sata_down_spd_limit() should check whether the link is online before
using the SPD value to determine how to limit the link speed. Factor
out onlineness test and test it from sata_down_spd_limit().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
ata_dev_disable() is about to be more tightly integrated into EH
logic. Move it to libata-eh.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Fix libata kernel-doc warnings:
Warning(linux-next-20090120//drivers/ata/libata-core.c:4720): Excess function parameter 'dev' description in 'ata_qc_new'
Warning(linux-next-20090120//drivers/ata/libata-scsi.c:428): No description found for parameter 'ap'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The forthcoming OCTEON SOC Compact Flash driver needs an additional
timing value that was not available in the ata_timing table. I add a
new column for dmack_hold time. The values were obtained from the
Compact Flash specification Rev 4.1.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
for SAS drivers.
Caught by Ke Wei (and team?) at Marvell.
Also, move the ata_scsi_ioctl export to libata-scsi.c, as that seems to be the
general trend.
Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
In a discussio with Jeff Garzik, he mentioned that the serialization
for the libata port probes only needs to be within the domain of a host.
This means that for the first port of each host (with ID 0), we don't
need to wait, so we can relax our serialization a little.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds a per host flag that allows drivers to opt in into
having its busses scanned in parallel.
Drivers that do not set this flag get their ports scanned in
the "original" sequence.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert WARN_ON() on command issue/completion paths to WARN_ON_ONCE()
so that libata doesn't spam the machine even when one of those
conditions triggers repeatedly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
According to the Compact Flash specification r4.1, PIO modes 5 and 6
do not use iordy.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The present AHCI driver seems to support SATA GEN 3 speed, but the related
messages should be modified.
Signed-off-by: Shane Huang <shane.huang@amd.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
As suggested by Linus: Don't do the libata init in 2 separate
steps with a global sync inbetween, but do it as one async step,
with a local sync before registering the device.
This cuts the boottime on my machine with 2 sata controllers down
significantly, and it seems to work. Would be nice if the libata
folks take a good look at this patch though..
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
This patch makes the libata port scanning asynchronous (per device).
There is a synchronization point before doing the actual disk scan
so that device ordering is not affected.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
The patchlet below blacklists NCQ on OCZ CORE v2 SSD drive(s). Even
though the drive advertises NCQ support with queue depth 1, it responds
with all-zeroes FIS to NCQ commands which triggers ata error handling
several times before the kernel decides to disable NCQ on the drive.
Signed-off-by: Lubomir Bulej <lubomir.bulej@dsrg.mff.cuni.cz>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
ata_port_detach() first made sure EH saw ATA_PFLAG_UNLOADING and then
assumed EH context belongs to it and performed detach operation
itself. However, UNLOADING doesn't disable all of EH and this could
lead to problems including triggering WARN_ON()'s in EH path.
This patch makes port detach behave more like other EH actions such
that ata_port_detach() requests EH to detach and waits for completion.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
When restoring SControl during detach, PMP links should be handled
first as changing SControl of the host link can affect SCR access of
PMP links.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
There currently are the following looping constructs.
* __ata_port_for_each_link() for all available links
* ata_port_for_each_link() for edge links
* ata_link_for_each_dev() for all devices
* ata_link_for_each_dev_reverse() for all devices in reverse order
Now there's a need for looping construct which is similar to
__ata_port_for_each_link() but iterates over PMP links before the host
link. Instead of adding another one with long name, do the following
cleanup.
* Implement and export ata_link_next() and ata_dev_next() which take
@mode parameter and can be used to build custom loop.
* Implement ata_for_each_link() and ata_for_each_dev() which take
looping mode explicitly.
The following iteration modes are implemented.
* ATA_LITER_EDGE : loop over edge links
* ATA_LITER_HOST_FIRST : loop over all links, host link first
* ATA_LITER_PMP_FIRST : loop over all links, PMP links first
* ATA_DITER_ENABLED : loop over enabled devices
* ATA_DITER_ENABLED_REVERSE : loop over enabled devices in reverse order
* ATA_DITER_ALL : loop over all devices
* ATA_DITER_ALL_REVERSE : loop over all devices in reverse order
This change removes exlicit device enabledness checks from many loops
and makes it clear which ones are iterated over in which direction.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Due to miscommunication, P/N was mistaken as firmware revision
strings. Update it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Some recent Seagate harddrives have firmware bug which causes FLUSH
CACHE to timeout under certain circumstances if NCQ is being used.
This can be worked around by disabling NCQ and fixed by updating the
firmware. Implement ATA_HORKAGE_FIRMWARE_UPDATE and blacklist these
devices.
The wiki page has been updated to contain information on this issue.
http://ata.wiki.kernel.org/index.php/Known_issues
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Phillip O'Donnell <phillip.odonnell@gmail.com> pointed out that the same
sign extension bug that was fixed in commit ba14a9c2 ("libata: Avoid
overflow in ata_tf_to_lba48() when tf->hba_lbal > 127") also appears to
exist in ata_tf_read_block(). Fix this by adding a cast to u64.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This patch reverts the following three commits which convert libata to
use block layer tagging.
43a49cbdf3e013e13bf62fca5ccf97
Although using block layer tagging is the right direction, due to the
tight coupling among tag number, data structure allocation and
hardware command slot allocation, libata doesn't work correctly with
the current conversion.
The biggest problem is guaranteeing that tag 0 is always used for
non-NCQ commands. Due to the way blk-tag is implemented and how SCSI
starts and finishes requests, such guarantee can't be made. I'm not
sure whether this would actually break any low level driver but it
doesn't look like a good idea to break such assumption given the
frailty of ATA controllers.
So, for the time being, keep using the old dumb in-libata qc
allocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axobe <jens.axboe@oracle.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
libata restores SControl on detach; however, trying to restore
non-zero DET can cause undeterministic behavior including PMP device
going offline till power cycling. Mask off DET when restoring
SControl.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
libata always uses PIO for ATAPI commands when the number of bytes to
transfer isn't multiple of 16 but quantum DAT72 chokes on odd bytes
PIO transfers. Implement a horkage to skip the mod16 check and apply
it to the quantum device.
This is reported by John Clark in the following thread.
http://thread.gmane.org/gmane.linux.ide/34748
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: John Clark <clarkjc@runbox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
libata currently imposes a UDMA5 max transfer rate and 200 sector max
transfer size for SATA devices that sit behind a pata-sata bridge. Lots
of devices have known good bridges that don't need this limit applied.
The MTRON SSD disks are such devices. Transfer rates are increased by
20-30% with the restriction removed.
So add a "blacklist" entry for the MTRON devices, with a flag indicating
that the bridge is known good.
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
In ata_tf_to_lba48(), when evaluating
(tf->hob_lbal & 0xff) << 24
the expression is promoted to signed int (since int can hold all values
of u8). However, if hob_lbal is 128 or more, then it is treated as a
negative signed value and sign-extended when promoted to u64 to | into
sectors, which leads to the MSB 32 bits of section getting set
incorrectly.
For example, Phillip O'Donnell <phillip.odonnell@gmail.com> reported
that a 1.5GB drive caused:
ata3.00: HPA detected: current 2930277168, native 18446744072344861488
where 2930277168 == 0xAEA87B30 and 18446744072344861488 == 0xffffffffaea87b30
which shows the problem when hob_lbal is 0xae.
Fix this by adding a cast to u64, just as is used by for hob_lbah and
hob_lbam in the function.
Reported-by: Phillip O'Donnell <phillip.odonnell@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Remove excess kernel-doc function parameter notation from drivers/ata/:
Warning(drivers/ata/libata-core.c:1622): Excess function parameter or struct member 'fn' description in 'ata_pio_queue_task'
Warning(drivers/ata/libata-core.c:4655): Excess function parameter or struct member 'err_mask' description in 'ata_qc_complete'
Warning(drivers/ata/ata_piix.c:751): Excess function parameter or struct member 'udma' description in 'do_pata_set_dmamode'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Fix libata missing kernel-doc:
Warning(lin2628-rc2//drivers/ata/libata-core.c:4562): No description
found for parameter 'tag'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
There were several places where only enabled devices should be
iterated over but device enabledness wasn't checked.
* IDENTIFY data 40 wire check in cable_is_40wire()
* xfer_mode/ncq_enabled saving in ata_scsi_error()
* DUBIOUS_XFER handling in ata_set_mode()
While at it, reformat comments in cable_is_40wire().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
libata currently has a pretty dumb ATA_MAX_QUEUE loop for finding
a free tag to use. Instead of fixing that up, convert libata to
using block layer tagging - gets rid of code in libata, and is also
much faster.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ap->port_task was not initialized if !CONFIG_ATA_SFF later triggering
lockdep warning. Make sure it's initialized.
Reported by Larry Finger.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
On user request (through sysfs), the IDLE IMMEDIATE command with UNLOAD
FEATURE as specified in ATA-7 is issued to the device and processing of
the request queue is stopped thereafter until the specified timeout
expires or user space asks to resume normal operation. This is supposed
to prevent the heads of a hard drive from accidentally crashing onto the
platter when a heavy shock is anticipated (like a falling laptop
expected to hit the floor). In fact, the whole port stops processing
commands until the timeout has expired in order to avoid any resets due
to failed commands on another device.
Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Explanation taken from the comment of ata_slave_link_init().
In libata, a port contains links and a link contains devices. There
is single host link but if a PMP is attached to it, there can be
multiple fan-out links. On SATA, there's usually a single device
connected to a link but PATA and SATA controllers emulating TF based
interface can have two - master and slave.
However, there are a few controllers which don't fit into this
abstraction too well - SATA controllers which emulate TF interface
with both master and slave devices but also have separate SCR
register sets for each device. These controllers need separate links
for physical link handling (e.g. onlineness, link speed) but should
be treated like a traditional M/S controller for everything else
(e.g. command issue, softreset).
slave_link is libata's way of handling this class of controllers
without impacting core layer too much. For anything other than
physical link handling, the default host link is used for both master
and slave. For physical link handling, separate @ap->slave_link is
used. All dirty details are implemented inside libata core layer.
From LLD's POV, the only difference is that prereset, hardreset and
postreset are called once more for the slave link, so the reset
sequence looks like the following.
prereset(M) -> prereset(S) -> hardreset(M) -> hardreset(S) ->
softreset(M) -> postreset(M) -> postreset(S)
Note that softreset is called only for the master. Softreset resets
both M/S by definition, so SRST on master should handle both (the
standard method will work just fine).
As slave_link excludes PMP support and only code paths which deal with
the attributes of physical link are affected, all the changes are
localized to libata.h, libata-core.c and libata-eh.c.
* ata_is_host_link() updated so that slave_link is considered as host
link too.
* iterator extended to iterate over the slave_link when using the
underbarred version.
* force param handling updated such that devno 16 is mapped to the
slave link/device.
* ata_link_on/offline() updated to return the combined result from
master and slave link. ata_phys_link_on/offline() are the direct
versions.
* EH autopsy and report are performed separately for master slave
links. Reset is udpated to implement the above described reset
sequence.
Except for reset update, most changes are minor, many of them just
modifying dev->link to ata_dev_phys_link(dev) or using phys online
test instead.
After this update, LLDs can take full advantage of per-dev SCR
registers by simply turning on slave link.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Implement __ata_port_next_link() and reimplement
__ata_port_for_each_link() and ata_port_for_each_link() using it.
This removes relatively large inlined code and makes iteration easier
to extend.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Logically, SCR access ops should take @link; however, there was no
compelling reason to convert all SCR access ops when adding @link
abstraction as there's one-to-one mapping between a port and a non-PMP
link. However, that assumption won't hold anymore with the scheduled
addition of slave link.
Make SCR access ops per-link.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Dave Müller sent a diff for the pata_oldpiix that highlighted a problem
where a lot of the ATA drivers assume dma_mode == 0 means "no DMA" while
the core code uses 0xFF.
This turns out to have other consequences such as code doing >= XFER_UDMA_0
also catching 0xFF as UDMAlots. Fortunately it doesn't generally affect
set_dma_mode, although some drivers call back into their own set mode code
from other points.
Having been through the drivers I've added helpers for using_udma/using_mwdma
dma_enabled so that people don't open code ranges that may change (eg if UDMA8
appears somewhere)
Thanks to David for the initial bits
[and added fix for pata_oldpiix from and signed-off-by Dave Mueller
<dave.mueller@gmx.ch> -jg]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Save SControl during probing and restore it on detach. This prevents
adjustments made by libata drivers to seep into the next driver which
gets attached (be it a libata one or not).
It's not clear whether SControl also needs to be restored on suspend.
The next system to have control (ACPI or kexec'd kernel) would
probably like to see the original SControl value but there's no
guarantee that a link is gonna keep working after SControl is adjusted
without a reset and adding a reset and modified recovery cycle soley
for this is an overkill. For now, do it only for detach.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Implement force params nohrst, nosrst and norst. This is to work
around reset related problems and ease debugging.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
- Add support for the RDC 1010 variant
- Rework the core library to have a read_id method. This allows the hacky
bits of it821x to go and prepares us for pata_hd
- Switch from WARN to BUG in ata_id_string as it will reboot if you get
it wrong so WARN won't be seen
- Allow the issue of command 0xFC on the 821x. This is needed to query
rebuild status.
- Tidy up printk formatting
- Do more ident rewriting on RAID volumes to handle firmware provided
ident data which is rather wonky
- Report the firmware revision and device layout in RAID mode
- Don't try and disable raid on the 8211 or RDC - they don't have the
relevant bits
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Fix a potential memory leak when ata_init() encounters an error.
Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Global and per-LLD ATAPI disable checks were done in the command issue
path probably because it was left out during EH conversion. On
affected machines, this can cause lots of warning messages. Move them
to where they belong - the probing path.
Reported by Chunbo Luo.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Chunbo Luo <chunbo.luo@windriver.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
ATA_TMOUT_INTERNAL which was 30secs were used for all internal
commands which is way too long when something goes wrong. This patch
implements command type based stepped timeouts. Different command
types can use different timeouts and each command type can use
different timeout values after timeouts.
ie. the initial timeout is set to a value which should cover most of
the cases but not too long so that run away cases don't delay things
too much. After the first try times out, the second try can use
longer timeout and if that one times out too, it can go for full 30sec
timeout.
IDENTIFYs use 5s - 10s - 30s timeout and all other commands use 5s -
10s timeouts.
This patch significantly cuts down the needed time to handle failure
cases while still allowing libata to work with nut job devices through
retries.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
libata has been using mix of jiffies and msecs for time druations.
This is getting confusing. As writing sub HZ values in jiffies is
PITA and msecs_to_jiffies() can't be used as initializer, unify unit
for all time durations to msecs. So, durations are in msecs and
deadlines are in jiffies. ata_deadline() is added to compute deadline
from a start time and duration in msecs.
While at it, drop now superflous _msec suffix from arguments and
rename @timeout to @deadline if it represents a fixed point in time
rather than duration.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
There's no reason to check whether to use DMA or not for no data
commands. Don't do it. While at it, make local variable using_pio in
atapi_xlat() set iff ATAPI_PROT_PIO is going to be used and rename
ata_check_atapi_dma() to atapi_check_dma() for consistency.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
I was hoping ATA_HORKAGE_NODMA | ATA_HORKAGE_SKIP_PM could keep it
happy but no even this doesn't work under certain configurations and
it's not like we can do anything useful with the cofig device anyway.
Replace ATA_HORKAGE_SKIP_PM with ATA_HORKAGE_DISABLE and use it for
the config device. This makes the device completely ignored by
libata.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
There's no reason to schedule LPM action after probing is complete
causing another EH iteration. Just schedule it together with probing
itself.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Originally, whole reset processing was done while the port is frozen
and SError was cleared during @postreset(). This had two race
conditions. 1: hotplug could occur after reset but before SError is
cleared and libata won't know about it. 2: hotplug could occur after
all the reset is complete but before the port is thawed. As all
events are cleared on thaw, the hotplug event would be lost.
Commit ac371987a8 kills the first race
by clearing SError during link resume but before link onlineness test.
However, this doesn't fix race #2 and in some cases clearing SError
after SRST is a good idea.
This patch solves this problem by cross checking link onlineness with
classification result after SError is cleared and port is thawed.
Reset is retried if link is online but all devices attached to the
link are unknown. As all devices will be revalidated, this one-way
check is enough to ensure that all devices are detected and
revalidated reliably.
This, luckily, also fixes the cases where host controller returns
bogus status while harddrive is spinning up after hotplug making
classification run before the device sends the first FIS and thus
causes misdetection.
Low level drivers can bypass the logic by setting class explicitly to
ATA_DEV_NONE if ever necessary (currently none requires this).
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The @online out parameter is supposed to set to true iff link is
online and reset succeeded as advertised in the function description
and callers are coded expecting that. However, sata_link_reset()
didn't behave this way on device readiness test failure. Fix it.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Export ata_eh_analyze_ncq_error() for subsequent use by sata_mv,
as suggested by Tejun.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Noticed by sparse
drivers/ata/libata-core.c:3380:12: warning: function 'ata_wait_after_reset' with external linkage has definition
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
None of these files use any of the functionality promised by
asm/semaphore.h. It's possible that they rely on it dragging in some
unrelated header file, but I can't build all these files, so we'll have
fix any build failures as they come up.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
We have a certain number of 'ATA' emulations often on CF or other flash
devices that are at best "loosely based" on the CF 1.1 standard. These
devices report themselves as disk but don't support the ATA minimal
command set only the CF 1.1 set.
Relax the PIO checking for devices reporting ATA rev 0, or no iordy
support, or CFA. Rework the code a bit as it was already messy and this
made it quite ugly.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The cable detect isolation patch inadvertently removed 40 wire short
cable handling. Put it back
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Currently, SATA softresets should do link onlineness check before
actually performing SRST protocol but it doesn't really belong to
softreset.
This patch moves onlineness check in softreset to ata_eh_reset() and
ata_eh_followup_srst_needed() to clean up code and help future sata_mv
changes which need clear separation between SCR and TF accesses.
sata_fsl is peculiar in that its softreset really isn't softreset but
combination of hardreset and softreset. This patch adds dummy private
->prereset to keep the current behavior but the driver really should
implement separate hard and soft resets and return -EAGAIN from
hardreset if it should be follwed by softreset.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Implement helpers to test whether PMP is supported, attached and
determine pmp number to use when issuing SRST to a link. While at it,
move ata_is_host_link() so that it's together with the two new PMP
helpers.
This change simplifies LLDs and helps making PMP support optional.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Most of PMP support code is already in libata-pmp.c. All that are in
libata-core.c are sata_pmp_port_ops and EXPORTs. Move them to
libata-pmp.c. Also, collect PMP related prototypes and declarations
in header files and move them right above of SFF stuff.
This change is to make PMP support optional.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Now that SFF support is completely separated out from the core layer,
it can be made optional. Add CONFIG_ATA_SFF and let SFF drivers
depend on it. If CONFIG_ATA_SFF isn't set, all codes in libata-sff.c
and data structures for SFF support are disabled. This saves good
number of bytes for small systems.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Now that SFF assumptions are separated out from non-SFF reset
sequence, port_ops->sff_dev_select() is no longer necessary for
non-SFF controllers. Kill ata_noop_dev_select() and ->sff_dev_select
initialization from base and other non-SFF port_ops.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Now that all SFF stuff is separated out of core layer, core layer
doesn't call ops->tf_read directly. It gets called only via
ops->qc_fill_rtf() for non-SFF drivers. This patch directly
implements private ops->qc_fill_rtf() for non-SFF controllers and kill
ops->tf_read().
This is much cleaner for non-SFF controllers as some of them have to
cache SFF register values in private data structure and report the
cached values via ops->tf_read(). Also, ops->tf_read() gets nasty for
controllers which don't have clear notion of TF registers when
operation is not in progress.
As this change makes default ops->qc_fill_rtf unnecessary, move
ata_sff_qc_fill_rtf() form ata_base_port_ops to ata_sff_port_ops where
it belongs.
Signed-off-by: Tejun Heo <htejun@gmail.com>
ata_qc_complete_multiple() took @finish_qc and called it on every qc
before completing it. This was to give opportunity to update TF cache
before ata_qc_complete() tries to fill result_tf. Now that result TF
is a separate operation, this is no longer necessary.
Update sata_sil24, which was the only user of this mechanism, such
that it implements its own ops->qc_fill_rtf() and drop @finish_qc from
ata_qc_complete_multiple().
Signed-off-by: Tejun Heo <htejun@gmail.com>
On command completion, ata_qc_complete() directly called ops->tf_read
to fill qc->result_tf. This patch adds ops->qc_fill_rtf to replace
hardcoded ops->tf_read usage.
ata_sff_qc_fill_rtf() which uses ops->tf_read to fill result_tf is
implemented and set in ata_base_port_ops and other ops tables which
don't inherit from ata_base_port_ops, so this patch doesn't introduce
any behavior change.
ops->qc_fill_rtf() is similar to ops->sff_tf_read() but can only be
called when a command finishes. As some non-SFF controllers don't
have TF registers defined unless they're associated with in-flight
commands, this limited operation makes life easier for those drivers
and help lifting SFF assumptions from libata core layer.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Previously, there were two ways to trigger follow-up SRST from
hardreset method - returning -EAGAIN and leaving all device classes
unmodified. Drivers never used the latter mechanism and the only use
case for the former was when hardreset couldn't classify.
Drop the latter mechanism and let -EAGAIN mean "perform follow-up SRST
if classification is required". This change removes unnecessary
follow-up SRSTs and simplifies reset implementations.
Signed-off-by: Tejun Heo <htejun@gmail.com>
If PMP fan-out reset fails and SCR isn't accessible, PMP should be
reset. This used to be tested by sata_pmp_std_hardreset() and
communicated to EH by -ERESTART. However, this logic is generic and
doesn't really have much to do with specific hardreset implementation.
This patch moves SCR access failure detection logic to ata_eh_reset()
where it belongs. As this makes sata_pmp_std_hardreset() identical to
sata_std_hardreset(), the function is killed and replaced with the
standard method.
Signed-off-by: Tejun Heo <htejun@gmail.com>
SError used to be cleared in ->postreset. This has small hotplug race
condition. If a device is plugged in after reset is complete but
postreset hasn't run yet, its hotplug event gets lost when SError is
cleared. This patch makes sata_link_resume() clear SError. This
kills the race condition and makes a lot of sense as some PMP and host
PHYs don't work properly without SError cleared.
This change makes sata_pmp_std_{pre|post}_reset()'s unnecessary as
they become identical to ata_std counterparts. It also simplifies
sata_pmp_hardreset() and ahci_vt8251_hardreset().
Signed-off-by: Tejun Heo <htejun@gmail.com>
Implement sata_std_hardreset(), which simply wraps around
sata_link_hardreset(). sata_std_hardreset() becomes new standard
hardreset method for sata_port_ops and sata_sff_hardreset() moves from
ata_base_port_ops to ata_sff_port_ops, which is where it really
belongs.
ata_is_builtin_hardreset() is added so that both
ata_std_error_handler() and ata_sff_error_handler() skip both builtin
hardresets if SCR isn't accessible.
piix_sidpr_hardreset() in ata_piix.c is identical to
sata_std_hardreset() in functionality and got replaced with the
standard function.
Signed-off-by: Tejun Heo <htejun@gmail.com>
sata_sff_hardreset() contains link readiness wait logic which isn't
SFF specific. Move that part into sata_link_hardreset(), which now
takes two more parameters - @online and @check_ready. Both are
optional. The former is out parameter for link onlineness after
reset. The latter is used to wait for link readiness after hardreset.
Users of sata_link_hardreset() is updated to use new funtionality and
ahci_hardreset() is updated to use sata_link_hardreset() instead of
sata_sff_hardreset(). This doesn't really cause any behavior change.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Factor out waiting logic (which is common to all ATA controllers) from
ata_sff_wait_ready() into ata_wait_ready(). ata_wait_ready() takes
@check_ready function pointer and uses it to poll for readiness. This
allows non-SFF controllers to use ata_wait_ready() to wait for link
readiness.
This patch also implements ata_wait_after_reset() - generic version of
ata_sff_wait_after_reset() - using ata_wait_ready().
ata_sff_wait_ready() is reimplemented using ata_wait_ready() and
ata_sff_check_ready(). Functionality remains the same.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Separate out generic ATA portion from ata_sff_postreset() into
ata_std_postreset() and implement ata_sff_postreset() using the std
version.
ata_base_port_ops now has ata_std_postreset() for its postreset and
ata_sff_port_ops overrides it to ata_sff_postreset().
This change affects pdc_adma, ahci, sata_fsl and sata_sil24. pdc_adma
now specifies postreset to ata_sff_postreset() explicitly. sata_fsl
and sata_sil24 now use ata_std_postreset() which makes no difference
to them. ahci now calls ata_std_postreset() from its own postreset
method, which causes no behavior difference.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Separate out generic ATA portion from ata_sff_prereset() into
ata_std_prereset() and implement ata_sff_prereset() using the std
version. Waiting for device readiness is the only SFF specific part.
ata_base_port_ops now has ata_std_prereset() for its prereset and
ata_sff_port_ops overrides it to ata_sff_prereset(). This change can
affect pdc_adma, ahci, sata_fsl and sata_sil24. pdc_adma implements
its own prereset using ata_sff_prereset() and the rest has hardreset
and thus are unaffected by this change.
This change reflects real world situation. There is no generic way to
wait for device readiness for non-SFF controllers and some of them
don't have any mechanism for that. Non-sff drivers which don't have
hardreset should wrap ata_std_prereset() and wait for device readiness
itself but there's no such driver now and isn't likely to be popular
in the future either.
Signed-off-by: Tejun Heo <htejun@gmail.com>
->sff_irq_clear() is called only from SFF interrupt handler, so there
is no reason to initialize it for non-SFF controllers. Also,
ata_sff_irq_clear() can handle both BMDMA and non-BMDMA SFF
controllers.
This patch kills ata_noop_irq_clear() and removes it from base
port_ops and sets ->sff_irq_clear to ata_sff_irq_clear() in sff
port_ops instead of bmdma port_ops.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Add sff_ prefix to SFF specific port ops.
This rename is in preparation of separating SFF support out of libata
core layer. This patch strictly renames ops and doesn't introduce any
behavior difference.
Signed-off-by: Tejun Heo <htejun@gmail.com>
SFF functions have confusing names. Some have sff prefix, some have
bmdma, some std, some pci and some none. Unify the naming by...
* SFF functions which are common to both BMDMA and non-BMDMA are
prefixed with ata_sff_.
* SFF functions which are specific to BMDMA are prefixed with
ata_bmdma_.
* SFF functions which are specific to PCI but apply to both BMDMA and
non-BMDMA are prefixed with ata_pci_sff_.
* SFF functions which are specific to PCI and BMDMA are prefixed with
ata_pci_bmdma_.
* Drop generic prefixes from LLD specific routines. For example,
bfin_std_dev_select -> bfin_dev_select.
The following renames are noteworthy.
ata_qc_issue_prot() -> ata_sff_qc_issue()
ata_pci_default_filter() -> ata_bmdma_mode_filter()
ata_dev_try_classify() -> ata_sff_dev_classify()
This rename is in preparation of separating SFF support out of libata
core layer. This patch strictly renames functions and doesn't
introduce any behavior difference.
Signed-off-by: Tejun Heo <htejun@gmail.com>
ata_flush_code() hasn't been in use for quite some time now. Kill it.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
ata_tf_to_lba[48]() currently return LBA in tf + 1 for
ata_read_native_max_address(). Make them return LBA and make it
global so that it can be used to read LBA off TF for other purposes.
ata_read_native_max_address() now adds 1 itself.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
ata_dev_configure() isn't tied to any controller interface except for
the probe debug message printing at the end of the function. Kill the
message.
This is to help separating out SFF support from core layer.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
* Move SFF related functions from libata-core.c to libata-sff.c.
ata_[bmdma_]sff_port_ops, ata_devchk(), ata_dev_try_classify(),
ata_std_dev_select(), ata_tf_to_host(), ata_busy_sleep(),
ata_wait_after_reset(), ata_wait_ready(), ata_bus_post_reset(),
ata_bus_softreset(), ata_bus_reset(), ata_std_softreset(),
sata_std_hardreset(), ata_fill_sg(), ata_fill_sg_dumb(),
ata_qc_prep(), ata_dump_qc_prep(), ata_data_xfer(),
ata_data_xfer_noirq(), ata_pio_sector(), ata_pio_sectors(),
atapi_send_cdb(), __atapi_pio_bytes(), atapi_pio_bytes(),
ata_hsm_ok_in_wq(), ata_hsm_qc_complete(), ata_hsm_move(),
ata_pio_task(), ata_qc_issue_prot(), ata_host_intr(),
ata_interrupt(), ata_std_ports()
* Make ata_pio_queue_task() global as it's now called from
libata-sff.c.
* Move SFF related stuff in include/linux/libata.h and
drivers/ata/libata.h into one place. While at it, move timing
constants into the global enum definition and fortify comments a
bit.
This patch strictly moves stuff around and as such doesn't cause any
functional difference.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
There is no reason to issue device select in read_id, it will be done
by ops->qc_issue() when IDENTIFY[_PACKET] is issued via
ata_exec_internal().
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Currently reset methods are not specified directly in the
ata_port_operations table. If a LLD wants to use custom reset
methods, it should construct and use a error_handler which uses those
reset methods. It's done this way for two reasons.
First, the ops table already contained too many methods and adding
four more of them would noticeably increase the amount of necessary
boilerplate code all over low level drivers.
Second, as ->error_handler uses those reset methods, it can get
confusing. ie. By overriding ->error_handler, those reset ops can be
made useless making layering a bit hazy.
Now that ops table uses inheritance, the first problem doesn't exist
anymore. The second isn't completely solved but is relieved by
providing default values - most drivers can just override what it has
implemented and don't have to concern itself about higher level
callbacks. In fact, there currently is no driver which actually
modifies error handling behavior. Drivers which override
->error_handler just wraps the standard error handler only to prepare
the controller for EH. I don't think making ops layering strict has
any noticeable benefit.
This patch makes ->prereset, ->softreset, ->hardreset, ->postreset and
their PMP counterparts propoer ops. Default ops are provided in the
base ops tables and drivers are converted to override individual reset
methods instead of creating custom error_handler.
* ata_std_error_handler() doesn't use sata_std_hardreset() if SCRs
aren't accessible. sata_promise doesn't need to use separate
error_handlers for PATA and SATA anymore.
* softreset is broken for sata_inic162x and sata_sx4. As libata now
always prefers hardreset, this doesn't really matter but the ops are
forced to NULL using ATA_OP_NULL for documentation purpose.
* pata_hpt374 needs to use different prereset for the first and second
PCI functions. This used to be done by branching from
hpt374_error_handler(). The proper way to do this is to use
separate ops and port_info tables for each function. Converted.
Signed-off-by: Tejun Heo <htejun@gmail.com>
port_info->private_data is currently used for two purposes - to record
private data about the port_info or to specify host->private_data to
use when allocating ata_host.
This overloading is confusing and counter-intuitive in that
port_info->private_data becomes host->private_data instead of
port->private_data. In addition, port_info and host don't correspond
to each other 1-to-1. Currently, the first non-NULL
port_info->private_data is used.
This patch makes port_info->private_data just be what it is -
private_data for the port_info where LLD can jot down extra info.
libata no longer sets host->private_data to the first non-NULL
port_info->private_data, @host_priv argument is added to
ata_pci_init_one() instead. LLDs which use ata_pci_init_one() can use
this argument to pass in pointer to host private data. LLDs which
don't should use init-register model anyway and can initialize
host->private_data directly.
Adding @host_priv instead of using init-register model for LLDs which
use ata_pci_init_one() is suggested by Alan Cox.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
ata_pci_init_one() is the only function which uses ops->irq_handler
and pi->sht. Other initialization functions take the same information
as arguments. This causes confusion and duplicate unused entries in
structures.
Make ata_pci_init_one() take sht as an argument and use ata_interrupt
implicitly. All current users use ata_interrupt and if different irq
handler is necessary open coding ata_pci_init_one() using
ata_prepare_sff_host() and ata_activate_sff_host can be done under ten
lines including error handling and driver which requires custom
interrupt handler is likely to require custom initialization anyway.
As ata_pci_init_one() was the last user of ops->irq_handler, this
patch also kills the field.
Signed-off-by: Tejun Heo <htejun@gmail.com>
libata lets low level drivers build ata_port_operations table and
register it with libata core layer. This allows low level drivers
high level of flexibility but also burdens them with lots of
boilerplate entries.
This becomes worse for drivers which support related similar
controllers which differ slightly. They share most of the operations
except for a few. However, the driver still needs to list all
operations for each variant. This results in large number of
duplicate entries, which is not only inefficient but also error-prone
as it becomes very difficult to tell what the actual differences are.
This duplicate boilerplates all over the low level drivers also make
updating the core layer exteremely difficult and error-prone. When
compounded with multi-branched development model, it ends up
accumulating inconsistencies over time. Some of those inconsistencies
cause immediate problems and fixed. Others just remain there dormant
making maintenance increasingly difficult.
To rectify the problem, this patch implements ata_port_operations
inheritance. To allow LLDs to easily re-use their own ops tables
overriding only specific methods, this patch implements poor man's
class inheritance. An ops table has ->inherits field which can be set
to any ops table as long as it doesn't create a loop. When the host
is started, the inheritance chain is followed and any operation which
isn't specified is taken from the nearest ancestor which has it
specified. This operation is called finalization and done only once
per an ops table and the LLD doesn't have to do anything special about
it other than making the ops table non-const such that libata can
update it.
libata provides four base ops tables lower drivers can inherit from -
base, sata, pmp, sff and bmdma. To avoid overriding these ops
accidentaly, these ops are declared const and LLDs should always
inherit these instead of using them directly.
After finalization, all the ops table are identical before and after
the patch except for setting .irq_handler to ata_interrupt in drivers
which didn't use to. The .irq_handler doesn't have any actual effect
and the field will soon be removed by later patch.
* sata_sx4 is still using old style EH and currently doesn't take
advantage of ops inheritance.
Signed-off-by: Tejun Heo <htejun@gmail.com>
->irq_clear() is used to clear IRQ bit of a SFF controller and isn't
useful for drivers which don't use libata SFF HSM implementation.
However, it's a required callback and many drivers implement their own
noop version as placeholder. This patch implements ata_noop_irq_clear
and use it to replace those custom placeholders.
Also, SFF drivers which don't support BMDMA don't need to use
ata_bmdma_irq_clear(). It becomes noop if BMDMA address isn't
initialized. Convert them to use ata_noop_irq_clear().
Signed-off-by: Tejun Heo <htejun@gmail.com>
ata_ehi_schedule_probe() was created to hide details of link-resuming
reset magic. Now that all the softreset workarounds are gone,
scheduling probe is very simple - set probe_mask and request RESET.
Kill ata_ehi_schedule_probe() and open code it. This also increases
consistency as ata_ehi_schedule_probe() couldn't cover individual
device probings so they were open-coded even when the helper existed.
While at it, define ATA_ALL_DEVICES as mask of all possible devices on
a link and always use it when requesting probe on link level for
simplicity and consistency. Setting extra bits in the probe_mask
doesn't hurt anybody.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Some controllers can't reliably record the initial D2H FIS after SATA
link is brought online for whatever reason. Advanced controllers
which don't have traditional TF register based interface often have
this problem as they don't really have the TF registers to update
while the controller and link are being initialized.
SKIP_D2H_BSY works around the problem by skipping the wait for device
readiness before issuing SRST, so for such controllers libata issues
SRST blindly and hopes for the best.
Now that libata defaults to hardreset, this workaround is no longer
necessary. For controllers which have support for hardreset, SRST is
never issued by itself. It is only issued as follow-up SRST for
device classification and PMP initialization, so there's no need to
wait for it from prereset.
Kill ATA_LFLAG_SKIP_D2H_BSY.
Signed-off-by: Tejun Heo <htejun@gmail.com>
