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
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
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
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
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
cris	fix random typos	2008-10-16 11:21:30 -07:00
crypto
development-process	Add the development process document	2008-10-16 11:51:30 -06:00
device-mapper
DocBook	WAN: syncppp.c is no longer used by any kernel code. Remove it.	2008-11-22 02:49:48 +01:00
driver-model
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
fault-injection
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
frv
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
ia64	.gitignore updates	2008-10-30 11:38:45 -07:00
ide
infiniband
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
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
make
mips
mn10300
mtd
namespaces
netlabel
networking	dccp ccid-2: Phase out the use of boolean Ack Vector sysctl	2008-12-08 01:19:06 -08:00
parisc
PCI	Create/use more directory structure in the Documentation/ tree.	2008-11-14 17:28:53 +00:00
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
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
s390
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
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
thermal
timers
tracers	tracing, doc: update mmiotrace documentation	2008-11-23 20:33:24 +01:00
uml
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
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
applying-patches.txt
atomic_ops.txt
basic_profiling.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
BUG-HUNTING
c2port.txt	Add c2 port support	2008-11-12 17:17:18 -08:00
cachetlb.txt
Changes
CodingStyle
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
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
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt	USB: add USB test and measurement class driver	2008-10-17 14:40:51 -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-attributes.txt
DMA-ISA-LPC.txt
DMA-mapping.txt
dontdiff	dontdiff: more updates to be closer to gitignore	2008-10-16 11:21:31 -07:00
edac.txt
eisa.txt
email-clients.txt	Documentation/email-clients.txt: add some info about gmail	2008-11-06 15:41:19 -08:00
exception.txt
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
HOWTO	Remove Andrew Morton's http://www.zip.com.au/~akpm/	2008-10-16 11:21:32 -07:00
hw_random.txt
ics932s401	ics932s401: new clock generator chip driver	2008-11-12 17:17:18 -08:00
initrd.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt	io mapping: improve documentation	2008-11-03 18:21:44 +01:00
IO-mapping.txt
iostats.txt
IPMI.txt
IRQ-affinity.txt
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt
kernel-docs.txt
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.txt
kobject.txt	kobject: Fix kobject_rename and !CONFIG_SYSFS	2008-10-16 09:24:52 -07:00
kprobes.txt
kref.txt
ldm.txt
leds-class.txt
local_ops.txt	documentation: local_ops fix on_each_cpu	2008-12-01 13:51:26 +01:00
lockdep-design.txt
lockstat.txt	lockstat: contend with points	2008-10-20 15:43:10 +02:00
logo.gif
logo.txt
magic-number.txt
Makefile
ManagementStyle	docs: fix ManagementStyle book name	2008-10-30 11:38:46 -07:00
markers.txt	markers: comment marker_synchronize_unregister() on data dependency	2008-11-28 16:47:41 +01:00
mca.txt
md.txt
memory-barriers.txt
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
mutex-design.txt
nmi_watchdog.txt	x86, nmi-watchdog: update procfs nmi_watchdog file documentation v2	2008-10-30 19:07:04 +01:00
nommu-mmap.txt
numastat.txt
oops-tracing.txt
parport-lowlevel.txt
parport.txt
pi-futex.txt
pnp.txt
preempt-locking.txt
printk-formats.txt	DOC: add printk-formats.txt	2008-11-12 17:17:17 -08:00
prio_tree.txt
rbtree.txt
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
robust-futexes.txt
rt-mutex-design.txt
rt-mutex.txt
rtc.txt
SAK.txt	Remove Andrew Morton's old email accounts	2008-10-16 11:21:32 -07:00
SecurityBugs
SELinux.txt
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
SM501.txt
Smack.txt
sparse.txt
spinlocks.txt
stable_api_nonsense.txt
stable_kernel_rules.txt	Update stable tree documentation	2008-10-29 15:03:49 -07:00
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
svga.txt
sysfs-rules.txt
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
unicode.txt
unshare.txt
VGA-softcursor.txt
video-output.txt
volatile-considered-harmful.txt
voyager.txt
zorro.txt