linux/drivers/s390/block/Kconfig
Josef 'Jeff' Sipek 08a8a0c59e [S390] dasd: fix double elevator_exit call when deadline iosched fails to load
I compiled the kernel without deadline, and the dasd code exits the old
scheduler (CFQ), fails to load the new one (deadline), and then things just
hang - with one of these (sorry about the weird chars - I copy & pasted it
from a 3270 console):

dasd(eckd): 0.0.0151: 3390/0A(CU:3990/01) Cyl:3338 Head:15 Sec:224
------------ cut here ------------
Badness at kernel/mutex.c:134
Modules linked in: dasd_eckd_mod dasd_mod
CPU: 0 Not tainted 2.6.25-rc3 #9
Process exe (pid: 538, task: 000000000d172000, ksp: 000000000d21ef88)
Krnl PSW : 0404000180000000 000000000022fb5c (mutex_lock_nested+0x2a4/0x2cc)
           R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0 EA:3
Krnl GPRS: 0000000000024218 000000000076fc78 0000000000000000 000000000000000f
           000000000022f92e 0000000000449898 000000000f921c00 000003e000162590
           00000000001539c4 000000000d172000 070000007fffffff 000000000d21f400
           000000000f8f2560 00000000002413f8 000000000022fb44 000000000d21f400
Krnl Code: 000000000022fb50: bf2f1000           icm     %r2,15,0(%r1)
           000000000022fb54: a774fef6           brc     7,22f940
           000000000022fb58: a7f40001           brc     15,22fb5a
          >000000000022fb5c: a7f4fef2           brc     15,22f940
           000000000022fb60: c0e5fffa112a       brasl   %r14,171db4
           000000000022fb66: 1222               ltr     %r2,%r2
           000000000022fb68: a784fedb           brc     8,22f91e
           000000000022fb6c: c010002a0086       larl    %r1,76fc78
Call Trace:
(<000000000022f92e> mutex_lock_nested+0x76/0x2cc)
 <00000000001539c4> elevator_exit+0x38/0x80
 <0000000000156ffe> blk_cleanup_queue+0x62/0x7c
 <000003e0001d5414> dasd_change_state+0xe0/0x8ec
 <000003e0001d5cae> dasd_set_target_state+0x8e/0x9c
 <000003e0001d5f74> dasd_generic_set_online+0x160/0x284
 <000003e00011e83a> dasd_eckd_set_online+0x2e/0x40
 <0000000000199bf4> ccw_device_set_online+0x170/0x2c0
 <0000000000199d9e> online_store_recog_and_online+0x5a/0x14c
 <000000000019a08a> online_store+0xbe/0x2ec
 <000000000018456c> dev_attr_store+0x38/0x58
 <000000000010efbc> sysfs_write_file+0x130/0x190
 <00000000000af582> vfs_write+0xb2/0x160
 <00000000000afc7c> sys_write+0x54/0x9c
 <0000000000025e16> sys32_write+0x2e/0x50
 <0000000000024218> sysc_noemu+0x10/0x16
 <0000000077e82bd2> 0x77e82bd2

Set elevator pointer to NULL in order to avoid double elevator_exit
calls when elevator_init call for deadline iosched fails.
Also make sure the dasd device driver depends on IOSCHED_DEADLINE so
the default IO scheduler of the dasd driver is present.

Signed-off-by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-04-17 07:46:55 +02:00

65 lines
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comment "S/390 block device drivers"
depends on S390 && BLOCK
config BLK_DEV_XPRAM
tristate "XPRAM disk support"
depends on S390 && BLOCK
help
Select this option if you want to use your expanded storage on S/390
or zSeries as a disk. This is useful as a _fast_ swap device if you
want to access more than 2G of memory when running in 31 bit mode.
This option is also available as a module which will be called
xpram. If unsure, say "N".
config DCSSBLK
tristate "DCSSBLK support"
depends on S390 && BLOCK
help
Support for dcss block device
config DASD
tristate "Support for DASD devices"
depends on CCW && BLOCK
select IOSCHED_DEADLINE
help
Enable this option if you want to access DASDs directly utilizing
S/390s channel subsystem commands. This is necessary for running
natively on a single image or an LPAR.
config DASD_PROFILE
bool "Profiling support for dasd devices"
depends on DASD
help
Enable this option if you want to see profiling information
in /proc/dasd/statistics.
config DASD_ECKD
tristate "Support for ECKD Disks"
depends on DASD
help
ECKD devices are the most commonly used devices. You should enable
this option unless you are very sure to have no ECKD device.
config DASD_FBA
tristate "Support for FBA Disks"
depends on DASD
help
Select this option to be able to access FBA devices. It is safe to
say "Y".
config DASD_DIAG
tristate "Support for DIAG access to Disks"
depends on DASD
help
Select this option if you want to use Diagnose250 command to access
Disks under VM. If you are not running under VM or unsure what it is,
say "N".
config DASD_EER
bool "Extended error reporting (EER)"
depends on DASD
help
This driver provides a character device interface to the
DASD extended error reporting. This is only needed if you want to
use applications written for the EER facility.