linux/drivers/char
Amit Shah 531295e63b virtio: console: Don't block entire guest if host doesn't read data
If the host is slow in reading data or doesn't read data at all,
blocking write calls not only blocked the program that called write()
but the entire guest itself.

To overcome this, let's not block till the host signals it has given
back the virtio ring element we passed it.  Instead, send the buffer to
the host and return to userspace.  This operation then becomes similar
to how non-blocking writes work, so let's use the existing code for this
path as well.

This code change also ensures blocking write calls do get blocked if
there's not enough room in the virtio ring as well as they don't return
-EAGAIN to userspace.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
CC: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-20 13:18:04 -07:00
..
agp drm/i915,agp/intel: Add second set of PCI-IDs for B43 2010-09-17 08:22:30 +01:00
hw_random Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2010-09-07 14:35:16 -07:00
ip2 ip2: return -EFAULT on copy_to_user errors 2010-08-23 18:17:21 -07:00
ipmi ipmi: fix hardcoded ipmi device exit path warning 2010-09-22 17:22:40 -07:00
mwave mwave: fix read buffer overflow 2009-09-24 07:21:03 -07:00
pcmcia Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2010-08-09 21:05:52 -07:00
rio 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
tpm tpm_tis: fix subsequent suspend failures 2010-07-26 10:25:45 +10:00
xilinx_hwicap of: Fix missing includes 2010-08-16 23:44:49 -06:00
.gitignore
amiserial.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
apm-emulation.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
applicom.c drivers/char/applicom.c: use memdup_user 2010-05-27 09:12:50 -07:00
applicom.h
bfin_jtag_comm.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
bfin-otp.c const: constify remaining file_operations 2009-10-01 16:11:11 -07:00
briq_panel.c tty: replace BKL with a new tty_lock 2010-08-10 13:47:43 -07:00
bsr.c of/address: Clean up function declarations 2010-08-01 01:42:42 -06:00
cd1865.h
consolemap.c
cp437.uni
cs5535_gpio.c drivers: Remove BKL from cs5535_gpio 2009-10-14 17:36:48 +02:00
cyclades.c tty: introduce wait_event_interruptible_tty 2010-08-10 13:47:43 -07:00
defkeymap.c_shipped
defkeymap.map
digi1.h
digiFep1.h
digiPCI.h
ds1302.c
ds1620.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
dsp56k.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
dtlk.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
efirtc.c efirtc: explicitly set llseek to no_llseek 2009-12-16 07:19:59 -08:00
epca.c epca: Kill the big kernel lock 2010-08-10 13:47:40 -07:00
epca.h
epcaconfig.h
generic_nvram.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
generic_serial.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
genrtc.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
hangcheck-timer.c Input: sysrq - drop tty argument form handle_sysrq() 2010-08-21 00:34:45 -07:00
hpet.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
hvc_beat.c Merge branch 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6 2010-02-25 15:38:37 -08:00
hvc_console.c Input: sysrq - drop tty argument form handle_sysrq() 2010-08-21 00:34:45 -07:00
hvc_console.h hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvc_irq.c
hvc_iseries.c Merge branch 'for-next' into for-linus 2010-03-08 16:55:37 +01:00
hvc_iucv.c Add param ops struct for hvc_iucv driver. 2010-08-11 23:04:16 +09:30
hvc_rtas.c hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvc_tile.c arch/tile: catch up on various minor cleanups. 2010-07-06 13:42:15 -04:00
hvc_udbg.c hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvc_vio.c hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvc_xen.c hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvcs.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
hvsi.c Input: sysrq - drop tty argument form handle_sysrq() 2010-08-21 00:34:45 -07:00
i8k.c procfs: Push down the bkl from ioctl 2010-05-17 03:06:12 +02:00
isicom.c isicom: kill off the BKL 2010-08-10 13:47:40 -07:00
istallion.c tty: introduce wait_event_interruptible_tty 2010-08-10 13:47:43 -07:00
Kconfig pc8736x_gpio: depends on X86_32 2010-08-12 08:43:29 -07:00
keyboard.c tty: Move the vt_tty field from the vc_data into the standard tty_port 2010-08-10 13:47:42 -07:00
lp.c lp: move compat_ioctl handling into lp.c 2009-12-10 22:55:36 +01:00
Makefile tty: implement BTM as mutex instead of BKL 2010-08-10 13:47:44 -07:00
mbcs.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
mbcs.h
mem.c char: Mark /dev/zero and /dev/kmem as not capable of writeback 2010-09-22 09:48:47 +02:00
misc.c char: add WARN_ON() in misc_deregister() 2010-08-09 20:45:06 -07:00
mmtimer.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
moxa.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
moxa.h
mspec.c tree-wide: fix assorted typos all over the place 2009-12-04 15:39:55 +01:00
mxser.c mxser: remove unnesesary NULL check 2010-08-10 13:47:45 -07:00
mxser.h
n_gsm.c drivers/char/n_gsm.c: add missing spin_unlock_irqrestore 2010-08-11 08:59:20 -07:00
n_hdlc.c tty: replace BKL with a new tty_lock 2010-08-10 13:47:43 -07:00
n_r3964.c tty: introduce wait_event_interruptible_tty 2010-08-10 13:47:43 -07:00
n_tty.c tty: Add EXTPROC support for LINEMODE 2010-08-10 13:47:39 -07:00
nozomi.c kfifo: fix kfifo miss use of nozami.c 2010-08-11 08:59:23 -07:00
nsc_gpio.c
nvram.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
nwbutton.c
nwbutton.h
nwflash.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
pc8736x_gpio.c drivers: Remove BKL from pc8736x_gpio 2009-10-14 17:36:52 +02:00
ppdev.c drivers/char/ppdev.c: use kasprintf 2010-05-27 09:12:50 -07:00
ps3flash.c drop unused dentry argument to ->fsync 2010-05-27 22:05:02 -04:00
pty.c tty: fix fu_list abuse 2010-08-18 08:35:47 -04:00
ramoops.c char drivers: RAM oops/panic logger 2010-05-27 09:12:50 -07:00
random.c random: Reorder struct entropy_store to remove padding on 64bits 2010-07-31 19:58:00 +08:00
raw.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
riscom8_reg.h
riscom8.c riscom8: kill use of lock_kernel 2010-08-10 13:47:40 -07:00
riscom8.h
rocket_int.h
rocket.c rocket: add a mutex_unlock() 2010-08-23 18:17:21 -07:00
rocket.h
rtc.c of/device: Replace struct of_device with struct platform_device 2010-08-06 09:25:50 -06:00
scc.h
scx200_gpio.c drivers: Remove BKL from scx200_gpio 2009-10-14 17:36:53 +02:00
selection.c tty: remove tty_lock_nested 2010-08-10 13:47:44 -07:00
ser_a2232.c headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
ser_a2232.h
ser_a2232fw.ax
ser_a2232fw.h
serial167.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
snsc_event.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
snsc.c
snsc.h
sonypi.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
specialix_io8.h
specialix.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
stallion.c stallion: prune lock_kernel calls 2010-08-10 13:47:40 -07:00
sx.c tty: replace BKL with a new tty_lock 2010-08-10 13:47:43 -07:00
sx.h
sxboards.h
sxwindow.h
synclink_gt.c synclink: add mutex_unlock() on error path 2010-08-23 18:17:21 -07:00
synclink.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
synclinkmp.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
sysrq.c Input: sysrq - drop tty argument form handle_sysrq() 2010-08-21 00:34:45 -07:00
tb0219.c mips: Remove BKL from tb0219 2009-10-14 17:36:53 +02:00
tlclk.c headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
toshiba.c tosh: Use non bkl ioctl 2010-01-04 12:31:21 -08:00
tty_audit.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
tty_buffer.c tty: fix obsolete comment on tty_insert_flip_string_fixed_flag 2010-05-21 09:34:30 -07:00
tty_io.c tty: fix tty_line must not be equal to number of allocated tty pointers in tty driver 2010-09-03 17:29:04 -07:00
tty_ioctl.c tty: Add EXTPROC support for LINEMODE 2010-08-10 13:47:39 -07:00
tty_ldisc.c tty: remove tty_lock_nested 2010-08-10 13:47:44 -07:00
tty_mutex.c tty: implement BTM as mutex instead of BKL 2010-08-10 13:47:44 -07:00
tty_port.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
uv_mmtimer.c x86, UV: Fix RTC latency bug by reading replicated cachelines 2010-01-27 11:33:53 +01:00
vc_screen.c tty: replace BKL with a new tty_lock 2010-08-10 13:47:43 -07:00
viotape.c of: Always use 'struct device.of_node' to get device node pointer. 2010-05-18 16:10:44 -06:00
virtio_console.c virtio: console: Don't block entire guest if host doesn't read data 2010-10-20 13:18:04 -07:00
vme_scc.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
vt_ioctl.c Input: use PIT_TICK_RATE in vt beep ioctl 2010-08-28 21:39:09 -07:00
vt.c vt: Fix console corruption on driver hand-over. 2010-09-03 17:29:03 -07:00