linux-stable/drivers/misc
Linus Torvalds 55db4c64ed Revert "tty: make receive_buf() return the amout of bytes received"
This reverts commit b1c43f82c5.

It was broken in so many ways, and results in random odd pty issues.

It re-introduced the buggy schedule_work() in flush_to_ldisc() that can
cause endless work-loops (see commit a5660b41af: "tty: fix endless
work loop when the buffer fills up").

It also used an "unsigned int" return value fo the ->receive_buf()
function, but then made multiple functions return a negative error code,
and didn't actually check for the error in the caller.

And it didn't actually work at all.  BenH bisected down odd tty behavior
to it:
  "It looks like the patch is causing some major malfunctions of the X
   server for me, possibly related to PTYs.  For example, cat'ing a
   large file in a gnome terminal hangs the kernel for -minutes- in a
   loop of what looks like flush_to_ldisc/workqueue code, (some ftrace
   data in the quoted bits further down).

   ...

   Some more data: It -looks- like what happens is that the
   flush_to_ldisc work queue entry constantly re-queues itself (because
   the PTY is full ?) and the workqueue thread will basically loop
   forver calling it without ever scheduling, thus starving the consumer
   process that could have emptied the PTY."

which is pretty much exactly the problem we fixed in a5660b41af.

Milton Miller pointed out the 'unsigned int' issue.

Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: Milton Miller <miltonm@bga.com>
Cc: Stefan Bigler <stefan.bigler@keymile.com>
Cc: Toby Gray <toby.gray@realvnc.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-04 06:33:24 +09:00
..
c2port Fix common misspellings 2011-03-31 11:26:23 -03:00
carma misc: Add CARMA DATA-FPGA Programmer support 2011-05-19 16:55:10 +10:00
cb710 misc: change to new flag variable 2011-03-17 14:05:34 +01:00
eeprom misc/at24: add more sanity checks for parameters 2010-12-24 02:14:17 -07:00
ibmasm Merge branch 'master' into for-next 2011-04-26 10:22:59 +02:00
iwmc3200top Fix common misspellings 2011-03-31 11:26:23 -03:00
lis3lv02d Move lis3lv02d drivers to drivers/misc 2011-03-21 17:59:36 +01:00
sgi-gru sanitize <linux/prefetch.h> usage 2011-05-20 12:50:29 -07:00
sgi-xp sgi-xpc: XPC fails to discover partitions with all nasids above 128 2010-11-25 06:50:40 +09:00
ti-st Revert "tty: make receive_buf() return the amout of bytes received" 2011-06-04 06:33:24 +09:00
ab8500-pwm.c misc: Add ab8500 pwm driver 2010-10-29 00:29:21 +02:00
ad525x_dpot-i2c.c drivers/misc/ad525x_dpot.c: new features 2010-10-26 16:52:14 -07:00
ad525x_dpot-spi.c drivers/misc/ad525x_dpot.c: new features 2010-10-26 16:52:14 -07:00
ad525x_dpot.c drivers/misc/ad525x_dpot.c: new features 2010-10-26 16:52:14 -07:00
ad525x_dpot.h ad525x_dpot: use correct rdac channel for ad5251/ad5252 2010-10-26 16:52:14 -07:00
apds990x.c drivers/misc: driver for APDS990X ALS and proximity sensors 2010-10-26 16:52:14 -07:00
apds9802als.c drivers/misc/apds9802als.c: put the device into runtime suspend after resume()/probe() is handled 2011-03-22 17:44:10 -07:00
arm-charlcd.c tree-wide: fix comment/printk typos 2010-11-01 15:38:34 -04:00
atmel-ssc.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
atmel_pwm.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
atmel_tclib.c drivers/misc/atmel_tclib.c: fix a memory leak 2011-03-22 17:44:11 -07:00
bh1770glc.c drivers/misc/bh1770glc.c: error handling in bh1770_power_state_store() 2010-11-12 07:55:31 -08:00
bh1780gli.c treewide: cleanup continuations and remove logging message whitespace 2011-04-26 10:24:37 +02:00
bmp085.c Fix common misspellings 2011-03-31 11:26:23 -03:00
cs5535-mfgpt.c cs5535: Fix section mismatch 2011-04-10 17:01:03 +02:00
ds1682.c sysfs: add struct file* to bin_attr callbacks 2010-05-21 09:37:31 -07:00
enclosure.c [SCSI] enclosure: fix error path - actually return ERR_PTR() on error 2010-07-27 12:03:48 -05:00
ep93xx_pwm.c drivers/misc/ep93xx_pwm.c: world-writable sysfs files 2011-03-22 17:44:11 -07:00
hmc6352.c drivers/misc/hmc6352.c: fix wrong return value checking for i2c_master_recv() 2011-03-22 17:44:10 -07:00
hpilo.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2010-10-22 19:36:42 -07:00
hpilo.h hpilo: fix pointer warning in ilo_ccb_setup 2010-08-09 20:45:05 -07:00
ics932s401.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ioc4.c ioc4: use static work_struct for ioc4_load_modules() 2010-12-24 16:14:20 +01:00
isl29003.c
isl29020.c drivers/misc/isl29020.c: remove incorrect kfree in isl29020_remove() 2010-11-25 06:50:47 +09:00
Kconfig Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2011-05-23 12:23:20 -07:00
kgdbts.c kgdbts: only use new asm-generic/ptrace.h api when needed 2011-06-01 16:35:01 +09:00
lkdtm.c lkdtm: prefix enum constants 2010-10-26 16:52:14 -07:00
Makefile Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2011-05-23 12:23:20 -07:00
pch_phub.c pch_phub: Support new device ML7223 2011-05-12 09:47:42 -07:00
phantom.c drivers/misc/phantom.c: add missing warning messages in phantom_probe() 2010-10-26 16:52:14 -07:00
pti.c Intel PTI implementaiton of MIPI 1149.7. 2011-05-13 16:31:00 -07:00
spear13xx_pcie_gadget.c treewide: cleanup continuations and remove logging message whitespace 2011-04-26 10:24:37 +02:00
ti_dac7512.c drivers/misc: add driver for Texas Instruments DAC7512 2009-12-15 08:53:25 -08:00
tifm_7xx1.c
tifm_core.c workqueue, freezer: unify spelling of 'freeze' + 'able' to 'freezable' 2011-02-16 17:48:59 +01:00
tsl2550.c tsl2550: Move from i2c/chips to misc 2010-03-13 20:56:54 +01:00
vmw_balloon.c workqueue, freezer: unify spelling of 'freeze' + 'able' to 'freezable' 2011-02-16 17:48:59 +01:00