linux-sg2042/Documentation
Tejun Heo 5f820f648c poll: allow f_op->poll to sleep
f_op->poll is the only vfs operation which is not allowed to sleep.  It's
because poll and select implementation used task state to synchronize
against wake ups, which doesn't have to be the case anymore as wait/wake
interface can now use custom wake up functions.  The non-sleep restriction
can be a bit tricky because ->poll is not called from an atomic context
and the result of accidentally sleeping in ->poll only shows up as
temporary busy looping when the timing is right or rather wrong.

This patch converts poll/select to use custom wake up function and use
separate triggered variable to synchronize against wake up events.  The
only added overhead is an extra function call during wake up and
negligible.

This patch removes the one non-sleep exception from vfs locking rules and
is beneficial to userland filesystem implementations like FUSE, 9p or
peculiar fs like spufs as it's very difficult for those to implement
non-sleeping poll method.

While at it, make the following cosmetic changes to make poll.h and
select.c checkpatch friendly.

* s/type * symbol/type *symbol/		   : three places in poll.h
* remove blank line before EXPORT_SYMBOL() : two places in select.c

Oleg: spotted missing barrier in poll_schedule_timeout()
Davide: spotted missing write barrier in pollwake()

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Brad Boyer <flar@allandria.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Roland McGrath <roland@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:12 -08:00
..
ABI mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
DocBook WAN: syncppp.c is no longer used by any kernel code. Remove it. 2008-11-22 02:49:48 +01:00
PCI Create/use more directory structure in the Documentation/ tree. 2008-11-14 17:28:53 +00:00
RCU Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-30 16:10:19 -08:00
accounting .gitignore updates 2008-10-30 11:38:45 -07:00
acpi ACPI: update debug parameter documentation 2008-11-07 21:45:29 -05:00
aoe aoe: user can ask driver to forget previously detected devices 2008-02-08 09:22:31 -08:00
arm Merge branch 'for-rmk' of git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6 into devel 2008-12-29 18:08:11 +00:00
auxdisplay .gitignore updates 2008-10-30 11:38:45 -07:00
blackfin Blackfin arch: add supporting for kgdb 2008-10-13 14:07:19 +08:00
block Documentation: remove reference to ll_rw_blk.c and moved drivers/block/elevator.c 2008-12-29 08:28:43 +01:00
blockdev Create/use more directory structure in the Documentation/ tree. 2008-11-14 17:28:53 +00:00
cdrom doc/cdrom: Trvial documentation error, file not present 2008-10-10 08:22:44 +02:00
cgroups freezer_cg: disable writing freezer.state of root cgroup 2008-11-12 17:17:16 -08:00
connector .gitignore updates 2008-10-30 11:38:45 -07:00
console Typo: fro -> from 2007-07-19 10:04:47 -07:00
controllers sched: add hierarchical accounting to cpu accounting controller 2008-11-11 12:13:28 +01:00
cpu-freq doc: Update sh cpufreq documentation. 2008-12-22 18:44:47 +09:00
cpuidle cpuidle: Add Documentation 2008-02-14 00:16:13 -05:00
cris fix random typos 2008-10-16 11:21:30 -07:00
crypto [CRYPTO] doc: Update api-intro.txt 2008-01-11 08:16:14 +11:00
development-process Add the development process document 2008-10-16 11:51:30 -06:00
device-mapper dm crypt: add documentation 2008-04-25 13:27:03 +01:00
driver-model Driver core: Update some prototypes in platform.txt 2008-02-02 15:14:49 -08:00
dvb V4L/DVB (9812): [PATCH] short help for Technisat cards to select the right configuration 2008-12-30 09:38:35 -02:00
early-userspace Documentation: Remove last references to BitKeeper. 2008-04-21 22:19:05 +00:00
fault-injection fault-injection: fix example scripts in documentation 2007-07-16 09:05:45 -07:00
fb [ARM] pxafb: add support for overlay1 and overlay2 as framebuffer devices 2008-12-29 18:00:04 +08:00
filesystems poll: allow f_op->poll to sleep 2009-01-06 15:59:12 -08:00
firmware_class firmware_sample_driver.c: fix coding style 2008-04-21 22:23:30 +00:00
frv move frv docs one level up 2008-02-03 15:54:28 +02:00
hwmon adt7462: new hwmon driver 2008-11-12 17:17:17 -08:00
i2c i2c: The i2c mailing list is moving 2008-10-30 15:55:47 +01:00
i2o documentation: convert the Documentation directory to UTF-8 2007-05-09 08:58:19 +02:00
ia64 .gitignore updates 2008-10-30 11:38:45 -07:00
ide gayle: add "doubler" parameter 2008-04-27 15:38:30 +02:00
infiniband IB/umad: Add P_Key index support 2007-10-09 19:59:15 -07:00
input Input: fix the example of an input device driver 2008-11-11 11:41:49 -05:00
ioctl UBI: document UBI ioctls 2008-12-09 15:59:07 +02:00
isdn Rationalise Randy's address a bit 2008-10-30 11:38:47 -07:00
ja_JP HOWTO: Sync patch for jp_JP/HOWTO 2008-10-29 15:03:50 -07:00
kbuild kbuild: document environment variables 2009-01-02 20:43:25 +01:00
kdump powerpc: Support for relocatable kdump kernel 2008-10-22 15:01:22 +11:00
ko_KR HOWTO: update misspelling and word incorrected 2007-12-17 10:33:19 -08:00
laptops Merge branch 'linus' into test 2008-10-23 00:11:07 -04:00
lguest lguest: move the initial guest page table creation code to the host 2008-12-30 09:26:11 +10:30
m68k [SCSI] 53c7xx: fix removal fallout 2008-01-11 18:22:30 -06:00
make Documentation/make/headers_install.txt 2007-10-17 08:43:05 -07:00
mips au1xxx-ide: fix MWDMA support 2008-04-26 22:25:22 +02:00
mn10300 mn10300: add the MN10300/AM33 architecture to the kernel 2008-02-08 09:22:30 -08:00
mtd [MTD] [NAND] nand_ecc.c: rewrite for improved performance 2008-08-16 10:55:33 +01:00
namespaces The namespaces compatibility list doc 2007-11-29 09:24:53 -08:00
netlabel Fix occurrences of "the the " 2007-05-09 08:57:56 +02:00
networking dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-12-08 01:19:06 -08:00
parisc
pcmcia .gitignore updates 2008-10-30 11:38:45 -07:00
power pm: document use of RTC in pm_trace 2008-10-16 11:21:29 -07:00
powerpc gianfar: Convert gianfar to an of_platform_driver 2008-12-16 15:29:15 -08:00
prctl generic, x86: add tests for prctl PR_GET_TSC and PR_SET_TSC 2008-04-19 19:19:55 +02:00
s390 [S390] cio: Exorcise cio_msg= from documentation. 2008-10-10 21:33:49 +02:00
scheduler Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-28 12:27:58 -08:00
scsi [SCSI] cxgb3i: Add cxgb3i iSCSI driver. 2008-12-30 10:45:33 -06:00
serial Create/use more directory structure in the Documentation/ tree. 2008-11-14 17:28:53 +00:00
sh sh: Kill off remaining CONFIG_SH_KGDB bits. 2008-12-22 18:44:05 +09:00
sound Merge branch 'topic/oxygen' into to-push 2008-12-25 11:40:30 +01:00
sparc sparc: Remove Documentation/sparc/sbus_drivers.txt 2008-08-29 02:15:25 -07:00
spi spi documentation: use __initdata on struct 2008-12-01 19:55:24 -08:00
sysctl mm: add dirty_background_bytes and dirty_bytes sysctls 2009-01-06 15:59:03 -08:00
telephony remove mention of CONFIG_KMOD from documentation 2008-07-22 19:24:29 +10:00
thermal thermal: update the documentation 2008-04-29 02:49:47 -04:00
timers hpet: /dev/hpet - fixes and cleanup 2008-07-31 18:45:41 +02:00
tracers tracing, doc: update mmiotrace documentation 2008-11-23 20:33:24 +01:00
uml Fix typos in /Documentation : 'U-Z' 2006-11-30 04:58:40 +01:00
usb Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-upstream 2009-01-02 13:17:13 +00:00
video4linux V4L/DVB (10157): Add USB ID for the Sil4701 radio from DealExtreme 2009-01-02 17:13:56 -02:00
vm mm: remove try_to_munlock from vmscan 2009-01-06 15:59:03 -08:00
w1 hdq: documentation for OMAP HDQ 2008-11-12 17:17:18 -08:00
watchdog .gitignore updates 2008-10-30 11:38:45 -07:00
x86 Merge branches 'x86/apic', 'x86/cleanups', 'x86/cpufeature', 'x86/crashdump', 'x86/debug', 'x86/defconfig', 'x86/detect-hyper', 'x86/doc', 'x86/dumpstack', 'x86/early-printk', 'x86/fpu', 'x86/idle', 'x86/io', 'x86/memory-corruption-check', 'x86/microcode', 'x86/mm', 'x86/mtrr', 'x86/nmi-watchdog', 'x86/pat2', 'x86/pci-ioapic-boot-irq-quirks', 'x86/ptrace', 'x86/quirks', 'x86/reboot', 'x86/setup-memory', 'x86/signal', 'x86/sparse-fixes', 'x86/time', 'x86/uv' and 'x86/xen' into x86/core 2008-12-23 16:27:23 +01:00
zh_CN Chinese: add translation of Codingstyle 2008-01-24 20:40:04 -08:00
00-INDEX Merge branch 'doc-subdirs' of git://git.kernel.org/pub/scm/linux/kernel/git/rdunlap/linux-docs 2008-11-15 11:51:03 -08:00
BUG-HUNTING Documentation: add hint about call traces & module symbols to BUG-HUNTING 2008-02-06 10:41:09 -08:00
Changes [x86 setup] Document grub < 0.93 as broken 2007-08-02 13:50:43 -04:00
CodingStyle documentation: update CodingStyle tips for Emacs users 2008-07-25 10:53:29 -07:00
DMA-API.txt DMA-API.txt: fix description of pci_map_sg/dma_map_sg scatterlists handling 2008-12-01 19:55:24 -08:00
DMA-ISA-LPC.txt Fix typos in /Documentation : 'T'' 2006-11-30 04:55:36 +01:00
DMA-attributes.txt powerpc/cell: Add DMA_ATTR_WEAK_ORDERING dma attribute and use in Cell IOMMU code 2008-07-22 10:39:36 +10:00
DMA-mapping.txt Documentation/DMA-mapping.txt: update for pci_dma_mapping_error() changes 2008-09-23 08:09:14 -07:00
HOWTO Remove Andrew Morton's http://www.zip.com.au/~akpm/ 2008-10-16 11:21:32 -07:00
IO-mapping.txt
IPMI.txt IPMI: new NMI handling 2007-10-18 14:37:32 -07:00
IRQ-affinity.txt genirq: Expose default irq affinity mask (take 3) 2008-06-05 15:18:30 +02:00
IRQ.txt [PATCH] genirq: irq: document what an IRQ is 2006-06-29 10:26:25 -07:00
Intel-IOMMU.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
Makefile docsrc: build Documentation/ sources 2008-08-12 16:07:30 -07:00
ManagementStyle docs: fix ManagementStyle book name 2008-10-30 11:38:46 -07:00
SAK.txt Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
SELinux.txt selinux: add support for installing a dummy policy (v2) 2008-08-27 08:54:08 +10:00
SM501.txt Tweak Documentation/SM501.txt 2007-10-17 08:43:06 -07:00
SecurityBugs
Smack.txt Smack: Simplified Mandatory Access Control Kernel 2008-02-05 09:44:20 -08:00
SubmitChecklist documentation: explain memory barriers 2008-10-16 11:21:32 -07:00
SubmittingDrivers Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
SubmittingPatches Merge branch 'docs' of git://git.lwn.net/linux-2.6 2008-10-16 12:18:16 -07:00
VGA-softcursor.txt
applying-patches.txt [PATCH] Docs update: typos, corrections and additions to applying-patches.txt 2006-01-10 08:01:54 -08:00
atomic_ops.txt documentation: atomic_add_unless() doesn't imply mb() on failure 2008-02-23 17:52:36 -08:00
basic_profiling.txt
binfmt_misc.txt documentation: convert the Documentation directory to UTF-8 2007-05-09 08:58:19 +02:00
braille-console.txt Basic braille screen reader support 2008-04-30 08:29:52 -07:00
bt8xxgpio.txt gpio: add bt8xxgpio driver 2008-07-25 10:53:30 -07:00
c2port.txt Add c2 port support 2008-11-12 17:17:18 -08:00
cachetlb.txt remove unused flush_tlb_pgtables 2007-10-19 11:53:34 -07:00
cpu-hotplug.txt x86: use possible_cpus=NUM to extend the possible cpus allowed 2008-12-18 12:08:05 +01:00
cpu-load.txt [PATCH] Documentation: CPU load calculation description 2007-03-01 14:53:39 -08:00
cpusets.txt container freezer: document the cgroup freezer subsystem. 2008-10-20 08:52:34 -07:00
cputopology.txt sysfs: add documentation to cputopology.txt for system cpumasks 2008-12-19 17:47:12 +10:30
credentials.txt CRED: Documentation 2008-11-14 10:39:26 +11:00
dcdbas.txt [PATCH] dcdbas: add Dell Systems Management Base Driver with sysfs support 2005-09-07 16:57:27 -07:00
debugging-modules.txt Documentation: Clarify when module debugging actually works. 2008-02-03 15:27:38 +02:00
debugging-via-ohci1394.txt firewire: fw-ohci: add option for remote debugging 2008-04-18 17:55:33 +02:00
dell_rbu.txt Fix typos in Documentation/: 'N'-'P' 2006-10-03 22:52:05 +02:00
devices.txt USB: add USB test and measurement class driver 2008-10-17 14:40:51 -07:00
dontdiff dontdiff: more updates to be closer to gitignore 2008-10-16 11:21:31 -07:00
edac.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
eisa.txt Fix typos in /Documentation : 'U-Z' 2006-11-30 04:58:40 +01:00
email-clients.txt Documentation/email-clients.txt: add some info about gmail 2008-11-06 15:41:19 -08:00
exception.txt Documentation: remove duplicated words 2006-10-03 22:57:56 +02:00
feature-removal-schedule.txt remove ide-scsi 2009-01-02 16:12:51 +01:00
ftrace.txt ftrace: improve documentation 2008-11-28 13:15:14 +01:00
gpio.txt gpiolib: request/free hooks 2008-10-16 11:21:40 -07:00
highuid.txt [SPARC]: Remove SunOS and Solaris binary support. 2008-04-21 15:10:15 -07:00
hw_random.txt hw_random doc updates 2008-03-24 19:22:19 -07:00
ics932s401 ics932s401: new clock generator chip driver 2008-11-12 17:17:18 -08:00
initrd.txt use the newc archive format as requested by initramfs 2008-02-03 14:54:41 +02:00
io-mapping.txt io mapping: improve documentation 2008-11-03 18:21:44 +01:00
io_ordering.txt
iostats.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
irqflags-tracing.txt [PATCH] lockdep: irqtrace subsystem, docs 2006-07-03 15:27:03 -07:00
isapnp.txt
java.txt Documentation/java.txt: typo and grammar fixes 2007-10-20 02:37:21 +02:00
kernel-doc-nano-HOWTO.txt sched: add kernel doc for the completion, fix kernel-doc-nano-HOWTO.txt 2008-08-26 10:26:54 +02:00
kernel-docs.txt doc: update to URL and status of kernel-docs.txt entry 2008-06-06 11:29:10 -07:00
kernel-parameters.txt Merge branch 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6 2008-12-28 12:33:21 -08:00
keys-request-key.txt keys: allow the callout data to be passed as a blob rather than a string 2008-04-29 08:06:16 -07:00
keys.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
kobject.txt kobject: Fix kobject_rename and !CONFIG_SYSFS 2008-10-16 09:24:52 -07:00
kprobes.txt powerpc/booke: Add kprobes support for booke style processors 2008-06-26 03:35:46 -05:00
kref.txt docs: convert kref semaphore to mutex 2008-02-06 10:41:09 -08:00
ldm.txt LDM: Fix for Windows Vista dynamic disks 2007-05-21 09:58:40 -07:00
leds-class.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
local_ops.txt documentation: local_ops fix on_each_cpu 2008-12-01 13:51:26 +01:00
lockdep-design.txt [PATCH] fix lockdep-design.txt 2006-10-11 11:14:24 -07:00
lockstat.txt lockstat: contend with points 2008-10-20 15:43:10 +02:00
logo.gif
logo.txt
magic-number.txt [SPARC]: Remove SunOS and Solaris binary support. 2008-04-21 15:10:15 -07:00
markers.txt markers: comment marker_synchronize_unregister() on data dependency 2008-11-28 16:47:41 +01:00
mca.txt The ps2esdi driver was marked as BROKEN more than two years ago due to being 2008-03-17 09:03:05 +01:00
md.txt md: Tidy up rdev_size_store a bit: 2008-07-21 14:22:18 +10:00
memory-barriers.txt read_barrier_depends arch fixlets 2008-05-14 10:05:18 -07:00
memory-hotplug.txt mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
memory.txt
mono.txt Fix "can not" in Documentation and Kconfig 2006-10-03 22:53:09 +02:00
mutex-design.txt Documentation: Add nested versions of mutex locks to docs 2007-10-20 00:15:26 +02:00
nmi_watchdog.txt x86, nmi-watchdog: update procfs nmi_watchdog file documentation v2 2008-10-30 19:07:04 +01:00
nommu-mmap.txt [PATCH] NOMMU: Make futexes work under NOMMU conditions 2006-09-27 08:26:15 -07:00
numastat.txt
oops-tracing.txt Taint kernel after WARN_ON(condition) 2008-04-29 08:05:59 -07:00
parport-lowlevel.txt plip: fix parport_register_device name parameter 2007-11-26 19:39:01 -08:00
parport.txt
pi-futex.txt fix a typo in Documentation/pi-futex.txt 2006-10-03 23:39:02 +02:00
pnp.txt Documentation: Replace obsolete "driverfs" with "sysfs". 2008-01-24 20:40:04 -08:00
preempt-locking.txt
printk-formats.txt DOC: add printk-formats.txt 2008-11-12 17:17:17 -08:00
prio_tree.txt Documentation: remove duplicated words 2006-10-03 22:57:56 +02:00
rbtree.txt [PATCH] Documentation/rbtree.txt 2007-02-11 10:51:35 -08:00
rfkill.txt rfkill: add master_switch_mode and EPO lock to rfkill and rfkill-input 2008-10-31 19:00:09 -04:00
robust-futex-ABI.txt Fix typos in /Documentation : 'U-Z' 2006-11-30 04:58:40 +01:00
robust-futexes.txt Fix typos in /Documentation : Misc 2006-11-30 05:21:10 +01:00
rt-mutex-design.txt [PATCH] typo fixes for rt-mutex-design.txt 2006-10-01 00:39:24 -07:00
rt-mutex.txt [PATCH] pi-futex: rt mutex docs 2006-06-27 17:32:47 -07:00
rtc.txt rtc: cleanup example code 2008-02-06 10:41:14 -08:00
serial-console.txt [PATCH] doc: more serial-console info 2006-03-25 08:23:00 -08:00
sgi-ioc4.txt
sgi-visws.txt
sparse.txt kbuild: sparse needs CF not CHECKFLAGS 2008-07-25 22:12:39 +02:00
spinlocks.txt Add additional examples in Documentation/spinlocks.txt 2008-04-11 13:21:14 -06:00
stable_api_nonsense.txt stable_api_nonsense.txt: Disambiguate the use of "this" by using "that" to refer to the syscall interface 2007-07-30 14:25:12 -07:00
stable_kernel_rules.txt Update stable tree documentation 2008-10-29 15:03:49 -07:00
svga.txt
sysfs-rules.txt sysfs-rules.txt: reword API stability statement 2008-07-21 21:54:59 -07:00
sysrq.txt Merge branch 'v28-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-10-20 13:19:56 -07:00
tracepoints.txt tracepoints: Documentation TPPROTO misspelt in Documentation/tracepoints.txt 2008-11-29 15:13:42 +01:00
unaligned-memory-access.txt introduce HAVE_EFFICIENT_UNALIGNED_ACCESS Kconfig symbol 2008-07-25 10:53:27 -07:00
unicode.txt
unshare.txt Documentation: remove duplicated words 2006-10-03 22:57:56 +02:00
video-output.txt output: Add output class document 2006-12-20 01:46:58 -05:00
volatile-considered-harmful.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
voyager.txt
zorro.txt