This is an variation on the patch sent by Christoph Hellwig which kills
file_count abuse by the Coda kernel module by moving the coda_flush
functionality into coda_release. However part of reason we were using the
coda_flush callback was to allow Coda to pass errors that occur during
writeback from the userspace cache manager back to close().
As Al Viro explained on linux-fsdevel, it is impossible to guarantee that
such errors can in fact be returned back to the caller. There are many
cases where the last reference to a file is not released by the close
system call and it is also impossible to pick some close as a 'last-close'
and delay it until all other references have been destroyed.
The CODA_STORE/CODA_RELEASE upcall combination is clearly a broken design,
and it is better to remove it completely.
Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Too many semicolons in this macro.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6:
[SPARC64]: fix section mismatch warning in mdesc.c
[SPARC64]: fix section mismatch warning in pci_sunv4
[SPARC64]: Stop using drivers/char/rtc.c
[SPARC64]: Convert parport to of_platform_driver.
[SPARC]: Implement fb_is_primary_device().
[SPARC64]: Fix virq decomposition.
[SPARC64]: Use KERN_ERR in IRQ manipulation error printks.
[SPARC64]: Do not flood log with failed DS messages.
[SPARC64]: Add proper multicast support to VNET driver.
[SPARC64]: Handle multiple domain-services-port nodes properly.
[SPARC64]: Improve VIO device naming further.
[SPARC]: Make sure dev_archdata is filled in for all devices.
[SPARC]: Define minimal struct dev_archdata, similarly to sparc64.
[SPARC]: Fix serial console device detection.
The current scheme works on static interpretation of text names, which
is wrong.
The output-device setting, for example, must be resolved via an alias
or similar to a full path name to the console device.
Paths also contain an optional set of 'options', which starts with a
colon at the end of the path. The option area is used to specify
which of two serial ports ('a' or 'b') the path refers to when a
device node drives multiple ports. 'a' is assumed if the option
specification is missing.
This was caught by the UltraSPARC-T1 simulator. The 'output-device'
property was set to 'ttya' and we didn't pick upon the fact that this
is an OBP alias set to '/virtual-devices/console'. Instead we saw it
as the first serial console device, instead of the hypervisor console.
The infrastructure is now there to take advantage of this to resolve
the console correctly even in multi-head situations in fbcon too.
Thanks to Greg Onufer for the bug report.
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'master' of ssh://master.kernel.org/pub/scm/linux/kernel/git/mchehab/v4l-dvb:
V4L/DVB (5880): wm8775/wm8739: Fix memory leak when unloading module
V4L/DVB (5877): radio-gemtek-pci: remove unused structure member
V4L/DVB (5871): Conexant 2388x: check for kthread_run
V4L/DVB (5869): Add check for valid control ID to v4l2_ctrl_next.
V4L/DVB (5867): videodev2.h: add missing <sys/time.h> for userspace
V4L/DVB (5866): ivtv: fix DMA timeout when capturing VBI + another stream
V4L/DVB (5865): Remove usage of HZ on ivtv driver, replacing by msecs_to_jiffies
V4L/DVB (5861): Use msecs_to_jiffies instead of HZ on bttv, cx88 and saa7134
V4L/DVB (5860): Use msecs_to_jiffies instead of HZ on some webcam drivers
V4L/DVB (5859): use msecs_to_jiffies on InfraRed RC5 timeout
V4L/DVB (5858): Use msecs_to_jiffies instead of HZ on media/video I2C drivers
V4L/DVB (5857): Use msecs_to_jiffies instead of HZ on radio drivers
V4L/DVB (5855): ivtv: fix Kconfig typo and refer to the driver homepage.
V4L/DVB (5854): ivtv: cleanup of driver messages
V4L/DVB (5853): ivtv: add support to suppress high volume i2c debug messages.
V4L/DVB (5852): ivtv: don't recompile needlessly
V4L/DVB (5851): ivtv: fix missing I2C_ALGOBIT config option
V4L/DVB (5850): ivtv: improve API command debugging
V4L/DVB (5848): Av7110: fix typo
* 'for-2.6.23' of master.kernel.org:/pub/scm/linux/kernel/git/arnd/cell-2.6: (37 commits)
[CELL] spufs: rework list management and associated locking
[CELL] oprofile: add support to OProfile for profiling CELL BE SPUs
[CELL] oprofile: enable SPU switch notification to detect currently active SPU tasks
[CELL] spu_base: locking cleanup
[CELL] cell: indexing of SPUs based on firmware vicinity properties
[CELL] spufs: integration of SPE affinity with the scheduller
[CELL] cell: add placement computation for scheduling of affinity contexts
[CELL] spufs: extension of spu_create to support affinity definition
[CELL] cell: add hardcoded spu vicinity information for QS20
[CELL] cell: add vicinity information on spus
[CELL] cell: add per BE structure with info about its SPUs
[CELL] spufs: use find_first_bit() instead of sched_find_first_bit()
[CELL] spufs: remove unused file argument from spufs_run_spu()
[CELL] spufs: change decrementer restore timing
[CELL] spufs: dont halt decrementer at restore step 47
[CELL] spufs: limit saving MFC_CNTL bits
[CELL] spufs: fix read and write for decr_status file
[CELL] spufs: fix decr_status meanings
[CELL] spufs: remove needless context save/restore code
[CELL] spufs: fix array size of channel index
...
When videodev2.h is included by an application, it needs to include
<sys/time.h> for the timeval struct.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This sorts out the various lists and related locks in the spu code.
In detail:
- the per-node free_spus and active_list are gone. Instead struct spu
gained an alloc_state member telling whether the spu is free or not
- the per-node spus array is now locked by a per-node mutex, which
takes over from the global spu_lock and the per-node active_mutex
- the spu_alloc* and spu_free function are gone as the state change is
now done inline in the spufs code. This allows some more sharing of
code for the affinity vs normal case and more efficient locking
- some little refactoring in the affinity code for this locking scheme
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
From: Maynard Johnson <mpjohn@us.ibm.com>
This patch updates the existing arch/powerpc/oprofile/op_model_cell.c
to add in the SPU profiling capabilities. In addition, a 'cell' subdirectory
was added to arch/powerpc/oprofile to hold Cell-specific SPU profiling code.
Exports spu_set_profile_private_kref and spu_get_profile_private_kref which
are used by OProfile to store private profile information in spufs data
structures.
Also incorporated several fixes from other patches (rrn). Check pointer
returned from kzalloc. Eliminated unnecessary cast. Better error
handling and cleanup in the related area. 64-bit unsigned long parameter
was being demoted to 32-bit unsigned int and eventually promoted back to
unsigned long.
Signed-off-by: Carl Love <carll@us.ibm.com>
Signed-off-by: Maynard Johnson <mpjohn@us.ibm.com>
Signed-off-by: Bob Nelson <rrnelson@us.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
This patch adds support for additional flags at spu_create, which relate
to the establishment of affinity between contexts and contexts to memory.
A fourth, optional, parameter is supported. This parameter represent
a affinity neighbor of the context being created, and is used when defining
SPU-SPU affinity.
Affinity is represented as a doubly linked list of spu_contexts.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
This patch adds affinity data to each spu instance.
A doubly linked list is created, meant to connect the spus
in the physical order they are placed in the BE. SPUs
near to memory should be marked as having memory affinity.
Adjustments of the fields acording to FW properties is done
in separate patches, one for CPBW, one for Malta (patch for
Malta under testing).
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Addition of a spufs-global "cbe_info" array. Each entry contains information
about one Cell/B.E. node, namelly:
* list of spus (both free and busy spus are in this list);
* list of free spus (replacing the static spu_list from spu_base.c)
* number of spus;
* number of reserved (non scheduleable) spus.
SPE affinity implementation actually requires only access to one spu per
BE node (since it implements its own pointer to walk through the other spus
of the ring) and the number of scheduleable spus (n_spus - non_sched_spus)
However having this more general structure can be useful for other
functionalities, concentrating per-cbe statistics / data.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
The decr_status in the LSCSA is confusedly used as two meanings:
* SPU decrementer was running
* SPU decrementer was wrapped as a result of adjust
and the code to set decr_status is missing.
This patch fixes these problems by using the decr_status argument as a
set of flags. This requires a rebuild of the shipped spu_restore code.
Signed-off-by: Masato Noguchi <Masato.Noguchi@jp.sony.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
This patch exports per-context statistics in spufs as long as spu
statistics in sysfs.
It was formed by merging:
"spufs: add spu stats in sysfs" From: Christoph Hellwig
"spufs: add stat file to spufs" From: Christoph Hellwig
"spufs: fix libassist accounting" From: Jeremy Kerr
"spusched: fix spu utilization statistics" From: Luke Browning
And some adjustments by myself, after suggestions on cbe-oss-dev.
Having separate patches was making the review process harder
than it should, as we end up integrating spus and ctx statistics
accounting much more than it was on the first implementation.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
The current SPU context saving procedure in SPUFS unexpectedly
restarts MFC when halting decrementer, because MFC_CNTL[Dh] is set
without MFC_CNTL[Sm]. This bug causes, for example, saving broken DMA
queues. Here is a patch to fix the problem.
Signed-off-by: Kazunori Asayama <asayama@sm.sony.co.jp>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
This patch adds support for investigating spus information after a
kernel crash event, through kdump vmcore file.
Implementation is based on xmon code, but the new functionality was
kept independent from xmon.
Signed-off-by: Lucio Jose Herculano Correia <luciojhc@br.ibm.com>
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
The pmi driver got simplified by removing support for multiple devices.
As there is no more than one pmi device per maschine, there is no need to
specify the device for listening and sending messages.
This way the caller (cbe_cpufreq) doesn't need to scan the device tree.
When registering the handler on a board without a pmi
interface, pmi.c will just return -ENODEV.
The patch that fixed the breakage of cell_defconfig has been
broken out of the earlier version of this patch. So this is
the version that applies cleanly on top of it.
Signed-off-by: Christian Krafft <krafft@de.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
The comparison with ZERO_SIZE_PTR in ZERO_OR_NULL_PTR() needs to be <=
(not just <) so that ZERO_OR_NULL_PTR(ZERO_SIZE_PTR) is 1.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
[ Duh! - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
[IA64] Prevent people from directly including <asm/rwsem.h>.
[IA64] remove time interpolator
[IA64] Convert to generic timekeeping/clocksource
[IA64] refresh some config files for 64K pagesize
[IA64] Delete iosapic_free_rte()
[IA64] fallocate system call
[IA64] Enable percpu vector domain for IA64_DIG
[IA64] Enable percpu vector domain for IA64_GENERIC
[IA64] Support irq migration across domain
[IA64] Add support for vector domain
[IA64] Add mapping table between irq and vector
[IA64] Check if irq is sharable
[IA64] Fix invalid irq vector assumption for iosapic
[IA64] Use dynamic irq for iosapic interrupts
[IA64] Use per iosapic lock for indirect iosapic register access
[IA64] Cleanup lock order in iosapic_register_intr
[IA64] Remove duplicated members in iosapic_rte_info
[IA64] Remove block structure for locking in iosapic.c
Remove time_interpolator code (This is generic code, but
only user was ia64. It has been superseded by the
CONFIG_GENERIC_TIME code).
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Peter Keilty <peter.keilty@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This is a merge of Peter Keilty's initial patch (which was
revived by Bob Picco) for this with Hidetoshi Seto's fixes
and scaling improvements.
Acked-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sfr/ofcons:
Create drivers/of/platform.c
Create linux/of_platorm.h
[SPARC/64] Rename some functions like PowerPC
Begin consolidation of of_device.h
Begin to consolidate of_device.c
Consolidate of_find_node_by routines
Consolidate of_get_next_child
Consolidate of_get_parent
Consolidate of_find_property
Consolidate of_device_is_compatible
Start split out of common open firmware code
Split out common parts of prom.h
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: appletouch - improve powersaving for Geyser3 devices
Input: lifebook - fix an oops on Panasonic CF-18
Input: document intended meaning of KEY_SWITCHVIDEOMODE
Input: switch to using seq_list_xxx helpers
Input: i8042 - give more trust to PNP data on i386
Input: add driver for Fujitsu serial touchscreens
Input: ads7846 - re-check pendown status before reporting events
Input: ads7846 - introduce sample settling delay
Input: xpad - add support for leds on xbox 360 pad
* master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh-2.6: (26 commits)
sh: intc - add support for SH7750 and its variants
sh: Move entry point code to .text.head.
sh: heartbeat: Shut up resource size warning.
sh: update r2d defconfig and fix SH7751R pci compliation
sh: Many symbol exports for nommu allmodconfig.
sh: zero terminate 8250 platform data for r2d board
sh: cpufreq: Fix up the build for SH-2.
sh: Make on-chip DMA channel selection explicit.
sh: Fix up CPU dependencies for on-chip DMAC.
sh: cpufreq: clock framework support.
sh: Support rate rounding for SH7722 FRQCR clocks.
sh: Implement clk_round_rate() in the clock framework.
sh: Fix up PCI section mismatch warnings.
sh: Wire up fallocate() syscall.
sh: intc - add support for 7780
sh: intc - improve group support
sh: Fix up SH-3 and SH-4 driver dependencies.
sh: push-switch: Correct license string.
sh: cpufreq: Fix driver dependencies and flag as broken.
sh: IPR/INTC2 IRQ setup consolidation.
...
* 'linus' of master.kernel.org:/pub/scm/linux/kernel/git/perex/alsa: (102 commits)
[ALSA] version 1.0.14
[ALSA] remove duplicate Logitech Quickcam USB ID in usbquirks.h
[ALSA] hda-codec - Fix input with STAC92xx
[ALSA] hda-intel: support for iMac 24'' released on 09/2006
[ALSA] hda-codec - Add quirk for Asus P5LD2
[ALSA] snd-ca0106: Add support for X-Fi Extreme Audio.
[ALSA] snd-emu10k1:Enable E-Mu 1616m notebook firmware loading.
[ALSA] snd-emu10k1: Initial support for E-Mu 1616 and 1616m.
[ALSA] cs46xx - Fix PM resume
[ALSA] hda: Enable SPDIF in/out on some stac9205 boards
[ALSA] timer: check for incorrect device state in non-debug compiles, too
[ALSA] snd-aoa-codec-onyx: fix typo
[ALSA] hda-codec - Add quirks for HP dx2200/dx2250
[ALSA] hda-codec - Rename HP model-specific quirks
[ALSA] hda-codec - Add quirk for HP Samba
[ALSA] hda-codec - Add LG LW20 line-in capture source
[ALSA] usb-audio - Fix AC3 with M-Audio Audiophile USB
[ALSA] hda: stac9202 mixer fix
[ALSA] Make s3c24xx_i2s_set_clkdiv() change the correct bits
[ALSA] hda-codec - Add LG LW20 si3054 modem id
...
* master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh64-2.6:
sh64: Flag sh64_get_page() as __init_refok.
sh64: Move entry point code to .text.head.
sh64: Fix up PCI section mismatch warnings.
sh64: Update cayman defconfig.
sh64: Wire up fallocate() syscall.
* 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/libata-dev: (29 commits)
libata: implement EH fast drain
libata: schedule probing after SError access failure during autopsy
libata: clear HOTPLUG flag after a reset
libata: reorganize ata_ehi_hotplugged()
libata: improve SCSI scan failure handling
libata: quickly trigger SATA SPD down after debouncing failed
libata: improve SATA PHY speed down logic
The SATA controller device ID is different according to
ahci: implement SCR_NOTIFICATION r/w
ahci: make NO_NCQ handling more consistent
libata: make ->scr_read/write callbacks return error code
libata: implement AC_ERR_NCQ
libata: improve EH report formatting
sata_sil24: separate out sil24_do_softreset()
sata_sil24: separate out sil24_exec_polled_cmd()
sata_sil24: replace sil24_update_tf() with sil24_read_tf()
ahci: separate out ahci_do_softreset()
ahci: separate out ahci_exec_polled_cmd()
ahci: separate out ahci_kick_engine()
ahci: use deadline instead of fixed timeout for 1st FIS for SRST
...
Andrew Morton:
[async_memcpy] is very wrong if both ASYNC_TX_KMAP_DST and
ASYNC_TX_KMAP_SRC can ever be set. We'll end up using the same kmap
slot for both src add dest and we get either corrupted data or a BUG.
Evgeniy Polyakov:
Btw, shouldn't it always be kmap_atomic() even if flag is not set.
That pages are usual one returned by alloc_page().
So fix the usage of kmap_atomic and kill the ASYNC_TX_KMAP_DST and
ASYNC_TX_KMAP_SRC flags.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6:
[SPARC64]: Fix two year old bug in early bootup asm.
[SPARC64]: Update defconfig.
[SPARC64]: Fix log message type in vio_create_one().
[SPARC64]: Tweak assertions in sun4v_build_virq().
[SPARC64]: Tweak kernel log messages in power_probe().
[SPARC64]: Fix handling of multiple vdc-port nodes.
[SPARC64]: Fix device type matching in VIO's devspec_show().
[SPARC64]: Fix MODULE_DEVICE_TABLE() specification in VDC and VNET.
[SPARC]: Add sys_fallocate() entries.
[SPARC64]: Use orderly_poweroff().
Since we have use like ~SLUB_DMA, we ought to have the type
set right in both cases.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In most cases, when EH is scheduled, all in-flight commands are
aborted causing EH to kick in immediately. However, in some cases
(especially with PMP), it's unclear which commands are affected by the
error condition and although aborting all in-flight commands work, it
isn't optimal and may cause unnecessary disruption. On the other
hand, waiting for in-flight commands to drain themselves can take up
to 30seconds.
This patch implements EH fast drain to handle such situations. It
gives in-flight commands some time to finish up but doesn't wait for
too long. After EH is scheduled, fast drain timer is started and if
no other completion occurs in ATA_EH_FASTDRAIN_INTERVAL all in-flight
commands are aborted. If any completion occurred in the interval, the
port is given another interval to finish up itself.
Currently ATA_EH_FASTDRAIN_INTERVAL is 3 secs which should be enough
for finishing up most commands.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
__ata_ehi_hotplugged() now has no users. Regorganize
ata_ehi_hotplugged() such that a new function ata_ehi_schedule_probe()
deals with scheduling probing. ata_ehi_hotplugged() calls it and
additionally marks hotplug specific flags. ata_ehi_schedule_probe()
will be used laster.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
sata_down_spd_limit() first reads the current SPD from SStatus and
limit the speed to the lower one of one below the current limit or one
below the current SPD in SStatus. SPD may not be accessible or valid
when SPD down is requested making sata_down_spd_limit() fail when it's
most needed.
This patch makes the current SPD cached after each successful reset
and forces GEN I speed (1.5Gbps) if neither of SStatus or the cached
value is valid, so sata_down_spd_limit() is now guaranteed to lower
the speed limit if lower speed is available.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Convert ->scr_read/write callbacks to return error code to better
indicate failure. This will help handling of SCR_NOTIFICATION.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
When an NCQ command fails, all commands in flight are aborted and the
offending one is reported using log page 10h. Depending on controller
characteristics and LLD implementation, all commands may appear as
having a device error due to shared TF status making it hard to
determine what's actually going on.
This patch adds AC_ERR_NCQ, marks the command reported by log page 10h
with it and print extra "<F>" after the error report for the command
to help distinguishing the offending command.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Requiring LLDs to format multiple error description messages properly
doesn't work too well. Help LLDs a bit by making ata_ehi_push_desc()
insert ", " on each invocation. __ata_ehi_push_desc() is the raw
version without the automatic separator.
While at it, make ehi_desc interface proper functions instead of
macros.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Thomas Gleixner
Jan Harkes
Nick Piggin
Linus Torvalds
David S. Miller
Hans Verkuil
Christoph Hellwig
Bob Nelson
Arnd Bergmann
Masato Noguchi
Andre Detsch
Kazunori Asayama
Christian Krafft
Roland Dreier
Robert P. J. Day
Tony Luck
Bob Picco
Franck Bui-Huu
Yoichi Yuasa
Ralf Baechle
Dan Williams
Al Viro
Tejun Heo