linux/drivers
Michael S. Tsirkin 0d4993563b vhost: fix barrier pairing
According to memory-barriers.txt, an smp memory barrier in guest
should always be paired with an smp memory barrier in host,
and I quote "a lack of appropriate pairing is almost certainly an
error". In case of vhost, failure to flush out used index
update before looking at the interrupt disable flag
could result in missed interrupts, resulting in
networking hang under stress.

This might happen when flags read bypasses used index write.
So we see interrupts disabled and do not interrupt, at the
same time guest writes flags value to enable interrupt,
reads an old used index value, thinks that
used ring is empty and waits for interrupt.

Note: the barrier we pair with here is in
drivers/virtio/virtio_ring.c, function
vring_enable_cb.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Juan Quintela <quintela@redhat.com>
2010-05-12 18:04:04 +03:00
..
accessibility
acpi Merge branch 'bugzilla-15749' into release 2010-04-16 16:08:07 -04:00
amba
ata libata: unlock HPA if device shrunk 2010-04-06 10:55:33 -04:00
atm 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
auxdisplay 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
base Revert "memory-hotplug: add 0x prefix to HEX block_size_bytes" 2010-04-09 10:05:33 -07:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 2010-04-09 11:50:29 -07:00
bluetooth 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
cdrom block: Consolidate phys_segment and hw_segment limits 2010-02-26 13:58:08 +01:00
char Merge branch 'urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2010-04-20 09:21:19 -07:00
clocksource 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
connector 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
cpufreq 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
cpuidle 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
crypto 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
dca 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
dio
dma 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
edac 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
eisa eisa: fix coding style for eisa bus code 2010-03-06 11:26:32 -08:00
firewire Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 2010-04-15 11:56:20 -07:00
firmware Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip 2010-04-07 11:02:23 -07:00
gpio drivers/gpio/timbgpio.c: add missing unlock 2010-04-07 08:38:02 -07:00
gpu Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-04-20 09:20:11 -07:00
hid Merge branch 'master' into export-slabh 2010-04-05 11:37:28 +09:00
hwmon hwmon: (applesmc) Add iMac9,1 and MacBookPro2,2 support 2010-04-14 16:14:10 +02:00
i2c 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
ide Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-2.6 2010-04-08 07:45:36 -07:00
idle 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
ieee1394 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
ieee802154
infiniband Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband 2010-04-09 11:53:06 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2010-04-15 11:49:55 -07:00
isdn Fix ISDN/Gigaset build failure 2010-04-19 11:53:17 -07:00
leds 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
lguest lguest: stop using KVM hypercall mechanism 2010-04-14 21:43:56 +09:30
macintosh device_attributes: add sysfs_attr_init() for dynamic attributes 2010-04-07 08:38:03 -07:00
mca
md 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
media device_attributes: add sysfs_attr_init() for dynamic attributes 2010-04-07 08:38:03 -07:00
memstick 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
message 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
mfd 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
misc Merge branch 'master' into export-slabh 2010-04-05 11:37:28 +09:00
mmc omap hsmmc: fix a bug in card remove scenario 2010-04-07 08:38:03 -07:00
mtd 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
net Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2010-05-10 22:53:41 -07:00
nubus 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
of Merge branch 'master' into export-slabh 2010-04-05 11:37:28 +09:00
oprofile 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
parisc 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
parport 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
pci Merge branch 'master' into export-slabh 2010-04-05 11:37:28 +09:00
pcmcia drivers/pcmcia: Add missing local_irq_restore 2010-04-17 17:54:38 +02:00
platform device_attributes: add sysfs_attr_init() for dynamic attributes 2010-04-07 08:38:03 -07:00
pnp Merge branches 'battery', 'bugzilla-14667', 'bugzilla-15096', 'bugzilla-15480', 'bugzilla-15521', 'bugzilla-15605', 'gpe-reference-counters', 'misc', 'pxm-fix' and 'video-random-key' into release 2010-04-06 17:06:22 -04:00
power 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
pps 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
ps3 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
rapidio
regulator 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
rtc rtc-mxc: multiple fixes in rtc-mxc probe method 2010-04-07 08:38:05 -07:00
s390 [S390] sclp_async: potential buffer overflow 2010-04-09 13:43:02 +02:00
sbus 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
scsi Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 2010-04-09 11:50:29 -07:00
serial serial_cs: MD55x support (PCMCIA GPRS/EDGE modem) (kernel 2.6.33) 2010-04-17 17:53:32 +02:00
sfi
sh 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
sn 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
spi 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
ssb MIPS: Fix SSB PCIcore IO resource management 2010-04-12 17:26:14 +01:00
staging staging/otus: include slab.h from usbdrv.h 2010-04-05 11:23:16 +09:00
tc 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
telephony
thermal drivers/thermal/thermal_sys.c: fix 'key f70f4b50 not in .data' in thermal_sys 2010-04-07 08:38:03 -07:00
uio 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
usb Merge branch 'master' into export-slabh 2010-04-05 11:37:28 +09:00
uwb 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
vhost vhost: fix barrier pairing 2010-05-12 18:04:04 +03:00
video mb862xxfb: update Valentin's email address 2010-04-07 08:38:04 -07:00
virtio 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
vlynq 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
w1 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
watchdog [WATCHDOG] max63xx driver depends on ioremap() 2010-04-16 12:26:32 +00:00
xen 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
zorro
Kconfig MFGPT: move clocksource menu 2010-03-06 11:26:28 -08:00
Makefile Merge branch 'origin' into devel-stable 2010-03-08 20:21:04 +00:00