9eef87da2a
This patch fixes the problem that system may stall if target's ->map_rq returns DM_MAPIO_REQUEUE in map_request(). E.g. stall happens on 1 CPU box when a dm-mpath device with queue_if_no_path bounces between all-paths-down and paths-up on I/O load. When target's ->map_rq returns DM_MAPIO_REQUEUE, map_request() requeues the request and returns to dm_request_fn(). Then, dm_request_fn() doesn't exit the I/O dispatching loop and continues processing the requeued request again. This map and requeue loop can be done with interrupt disabled, so 1 CPU system can be stalled if this situation happens. For example, commands below can stall my 1 CPU box within 1 minute or so: # dmsetup table mp mp: 0 2097152 multipath 1 queue_if_no_path 0 1 1 service-time 0 1 2 8:144 1 1 # while true; do dd if=/dev/mapper/mp of=/dev/null bs=1M count=100; done & # while true; do \ > dmsetup message mp 0 "fail_path 8:144" \ > dmsetup suspend --noflush mp \ > dmsetup resume mp \ > dmsetup message mp 0 "reinstate_path 8:144" \ > done To fix the problem above, this patch changes dm_request_fn() to exit the I/O dispatching loop once if a request is requeued in map_request(). Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: stable@kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com> |
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accessibility | ||
acpi | ||
amba | ||
ata | ||
atm | ||
auxdisplay | ||
base | ||
block | ||
bluetooth | ||
cdrom | ||
char | ||
clocksource | ||
connector | ||
cpufreq | ||
cpuidle | ||
crypto | ||
dca | ||
dio | ||
dma | ||
edac | ||
eisa | ||
firewire | ||
firmware | ||
gpio | ||
gpu | ||
hid | ||
hwmon | ||
i2c | ||
ide | ||
idle | ||
ieee1394 | ||
ieee802154 | ||
infiniband | ||
input | ||
isdn | ||
leds | ||
lguest | ||
macintosh | ||
mca | ||
md | ||
media | ||
memstick | ||
message | ||
mfd | ||
misc | ||
mmc | ||
mtd | ||
net | ||
nubus | ||
of | ||
oprofile | ||
parisc | ||
parport | ||
pci | ||
pcmcia | ||
platform | ||
pnp | ||
power | ||
pps | ||
ps3 | ||
rapidio | ||
regulator | ||
rtc | ||
s390 | ||
sbus | ||
scsi | ||
serial | ||
sfi | ||
sh | ||
sn | ||
spi | ||
ssb | ||
staging | ||
tc | ||
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thermal | ||
uio | ||
usb | ||
uwb | ||
video | ||
virtio | ||
vlynq | ||
w1 | ||
watchdog | ||
xen | ||
zorro | ||
Kconfig | ||
Makefile |