Linus Torvalds 81de916f19 tty_buffer: get rid of 'seen_tail' logic in flush_to_ldisc ... The flush_to_ldisc() work entry has special logic to notice when it has seen the original tail of the data queue, and it avoids continuing the flush if it sees that _original_ tail rather than the current tail. This logic can trigger in case somebody is constantly adding new data to the tty while the flushing is active - and the intent is to avoid excessive CPU usage while flushing the tty, especially as we used to do this from a softirq context which made it non-preemptible. However, since we no longer re-arm the work-queue from within itself (because that causes other trouble: see commit a5660b41af "tty: fix endless work loop when the buffer fills up"), this just leads to possible hung tty's (most easily seen in SMP and with a test-program that floods a pty with data - nobody seems to have reported this for any real-life situation yet). And since the workqueue isn't done from timers and softirq's any more, it's doubtful whether the CPU useage issue is really relevant any more. So just remove the logic entirely, and see if anybody ever notices. Alternatively, we might want to re-introduce the "re-arm the work" for just this case, but then we'd have to re-introduce the delayed work model or some explicit timer, which really doesn't seem worth it for this. Reported-and-tested-by: Guillaume Chazarain <guichaz@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2011-06-08 07:46:30 -07:00
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accessibility	…
acpi	Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6	2011-05-29 11:19:16 -07:00
amba	ARM: 6829/1: amba: make hardcoded periphid override hardware	2011-05-26 10:33:34 +01:00
ata	Merge branch 'for-2.6.40/core' of git://git.kernel.dk/linux-2.6-block	2011-05-25 09:14:07 -07:00
atm	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6	2011-05-20 13:43:21 -07:00
auxdisplay	…
base	mm: per-node vmstat: show proper vmstats	2011-05-25 08:39:07 -07:00
bcma	drivers/bcma/host_pci.c needs slab.h	2011-05-26 17:12:32 -07:00
block	Merge branch 'for-linus' of git://git.kernel.dk/linux-block	2011-06-04 08:11:26 +09:00
bluetooth	Revert "tty: make receive_buf() return the amout of bytes received"	2011-06-04 06:33:24 +09:00
cdrom	block: fix mismerge of the DISK_EVENT_MEDIA_CHANGE removal	2011-06-02 05:29:19 +09:00
char	virtio console: don't manually set or finalize VIRTIO_CONSOLE_F_MULTIPORT.	2011-05-30 11:14:13 +09:30
clk	…
clocksource	Revert "clocksource: sh_cmt: Runtime PM support"	2011-05-31 15:26:42 +09:00
connector	…
cpufreq	cpufreq: make DB8500 cpufreq driver compile	2011-05-24 22:20:14 +02:00
cpuidle	Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6	2011-05-29 11:18:09 -07:00
crypto	[S390] ap: skip device registration on type probe failure	2011-05-23 10:24:29 +02:00
dca	…
dio	…
dma	dmaengine: shdma: fix a regression: initialise DMA channels for memcpy	2011-06-02 14:40:43 +09:00
edac	edac,rcu: use synchronize_rcu() instead of call_rcu()+rcu_barrier()	2011-05-26 17:12:37 -07:00
eisa	…
firewire	…
firmware	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2011-05-23 09:12:26 -07:00
gpio	arm gpio drivers: make them 'depends on ARM'	2011-05-29 14:06:42 -07:00
gpu	Merge branch 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6	2011-06-07 19:09:26 -07:00
hid	Merge branch 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6	2011-05-23 12:33:02 -07:00
hwmon	hwmon: (max6642): Better chip detection schema	2011-06-04 10:34:28 -07:00
hwspinlock	…
i2c	mfd: Use mfd cell platform_data for timberdale cells platform bits	2011-05-26 19:45:05 +02:00
ide	block: fix mismerge of the DISK_EVENT_MEDIA_CHANGE removal	2011-06-02 05:29:19 +09:00
idle	…
ieee802154	…
infiniband	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband	2011-05-26 12:13:57 -07:00
input	Revert "tty: make receive_buf() return the amout of bytes received"	2011-06-04 06:33:24 +09:00
isdn	Revert "tty: make receive_buf() return the amout of bytes received"	2011-06-04 06:33:24 +09:00
leds	leds: Add ASIC3 LED support	2011-05-26 19:45:46 +02:00
lguest	…
macintosh	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2011-05-23 09:12:26 -07:00
mca	…
md	dm kcopyd: return client directly and not through a pointer	2011-05-29 13:03:13 +01:00
media	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6	2011-05-27 10:14:22 -07:00
memstick	…
message	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2011-05-23 09:12:26 -07:00
mfd	mfd: Fix build breakage caused by tps65910 gpio directory move	2011-05-28 08:38:55 +02:00
misc	Revert "tty: make receive_buf() return the amout of bytes received"	2011-06-04 06:33:24 +09:00
mmc	ARM: OMAP4: MMC: no regulator off during probe for eMMC	2011-06-01 02:25:04 -07:00
mtd	Merge git://git.infradead.org/mtd-2.6	2011-05-27 20:06:53 -07:00
net	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6	2011-06-04 23:16:00 +09:00
nfc	…
nubus	…
of	Merge branch 'devicetree/arm-next' of git://git.secretlab.ca/git/linux-2.6 into devel-stable	2011-05-25 00:08:17 +01:00
oprofile	oprofile: Use linux/mutex.h	2011-05-24 12:45:59 +02:00
parisc	…
parport	Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6	2011-05-26 13:19:00 -07:00
pci	Merge git://git.infradead.org/iommu-2.6	2011-06-02 05:48:50 +09:00
pcmcia	…
platform	Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mjg59/platform-drivers-x86	2011-05-29 11:44:33 -07:00
pnp	…
power	Merge git://git.infradead.org/battery-2.6	2011-05-27 10:12:35 -07:00
pps	…
ps3	…
ptp	ptp: Added a clock driver for the National Semiconductor PHYTER.	2011-05-23 13:10:23 -07:00
rapidio	rapidio: fix default routing initialization	2011-05-18 02:55:22 -07:00
regulator	regulator: Fix _regulator_get_voltage if get_voltage callback is NULL	2011-05-27 10:49:30 +01:00
rtc	drivers/rtc/rtc-mxc.c: remove defines already included in rtc.h	2011-05-26 17:12:33 -07:00
s390	[S390] qdio: Split SBAL entry flags	2011-06-06 14:14:56 +02:00
sbus	…
scsi	[SCSI] Fix oops caused by queue refcounting failure	2011-06-02 18:34:43 +09:00
sfi	…
sh	Merge branch 'sh/genirq-threading' into sh-latest	2011-05-23 11:36:14 +09:00
sn	…
spi	spi/spi_bfin_sport: new driver for a SPI bus via the Blackfin SPORT peripheral	2011-05-27 01:23:54 -06:00
ssb	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6	2011-05-20 13:43:21 -07:00
staging	Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6	2011-05-26 13:19:00 -07:00
target	[SCSI] target: Convert TASK_ATTR to scsi_tcq.h definitions	2011-05-24 13:03:56 -04:00
tc	…
telephony	…
thermal	…
tty	tty_buffer: get rid of 'seen_tail' logic in flush_to_ldisc	2011-06-08 07:46:30 -07:00
uio	…
usb	usb: remove bad dput after dentry_unhash	2011-06-03 18:43:00 -04:00
uwb	…
vhost	vhost: support event index	2011-05-30 11:14:15 +09:30
video	video: Fix use-after-free by vga16fb on rmmod	2011-06-06 18:14:45 +09:00
virtio	virtio: add api for delayed callbacks	2011-05-30 11:14:16 +09:30
vlynq	…
w1	w1: add Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC support	2011-05-26 17:12:38 -07:00
watchdog	mfd: Use mfd cell platform_data for rdc321x cells platform bits	2011-05-26 19:45:06 +02:00
xen	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem	2011-05-26 10:50:56 -07:00
zorro	…
Kconfig	ptp: Added a brand new class driver for ptp clocks.	2011-05-23 13:01:00 -07:00
Makefile	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx	2011-05-28 12:35:15 -07:00