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Petr Uzel fd51469fb6 block: kill loop_mutex 
Following steps lead to deadlock in kernel:

dd if=/dev/zero of=img bs=512 count=1000
losetup -f img
mkfs.ext2 /dev/loop0
mount -t ext2 -o loop /dev/loop0 mnt
umount mnt/

Stacktrace:
[<c102ec04>] irq_exit+0x36/0x59
[<c101502c>] smp_apic_timer_interrupt+0x6b/0x75
[<c127f639>] apic_timer_interrupt+0x31/0x38
[<c101df88>] mutex_spin_on_owner+0x54/0x5b
[<fe2250e9>] lo_release+0x12/0x67 [loop]
[<c10c4eae>] __blkdev_put+0x7c/0x10c
[<c10a4da5>] fput+0xd5/0x1aa
[<fe2250cf>] loop_clr_fd+0x1a9/0x1b1 [loop]
[<fe225110>] lo_release+0x39/0x67 [loop]
[<c10c4eae>] __blkdev_put+0x7c/0x10c
[<c10a59d9>] deactivate_locked_super+0x17/0x36
[<c10b6f37>] sys_umount+0x27e/0x2a5
[<c10b6f69>] sys_oldumount+0xb/0xe
[<c1002897>] sysenter_do_call+0x12/0x26
[<ffffffff>] 0xffffffff

Regression since 2a48fc0ab2, which introduced the private
loop_mutex as part of the BKL removal process.

As per [1], the mutex can be safely removed.

[1] http://www.gossamer-threads.com/lists/linux/kernel/1341930

Addresses: https://bugzilla.novell.com/show_bug.cgi?id=669394
Addresses: https://bugzilla.kernel.org/show_bug.cgi?id=29172

Signed-off-by: Petr Uzel <petr.uzel@suse.cz>
Cc: stable@kernel.org
Reviewed-by: Nikanth Karthikesan <knikanth@suse.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-03 11:53:25 -05:00
..
aoe drivers/block/aoe/Makefile: replace the use of <module>-objs with <module>-y 2011-01-19 08:25:02 -07:00
drbd Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
paride Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl 2010-10-22 10:52:56 -07:00
amiflop.c block: fix amiga and atari floppy driver compile warning 2010-11-15 19:32:43 +01:00
ataflop.c block: fix amiga and atari floppy driver compile warning 2010-11-15 19:32:43 +01:00
brd.c Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block 2010-10-22 17:07:18 -07:00
cciss_cmd.h cciss: reinstate proper FIFO order of command queue list 2011-01-10 21:50:33 +01:00
cciss_scsi.c SCSI host lock push-down 2010-11-16 13:33:23 -08:00
cciss_scsi.h
cciss.c cciss: make cciss_revalidate not loop through CISS_MAX_LUNS volumes unnecessarily. 2011-01-19 08:25:02 -07:00
cciss.h Merge branch 'for-2.6.38/drivers' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:50:24 -08:00
cpqarray.c block: autoconvert trivial BKL users to private mutex 2010-10-05 15:01:10 +02:00
cpqarray.h
cryptoloop.c
DAC960.c Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl 2010-10-22 10:52:56 -07:00
DAC960.h
floppy.c Fix over-zealous flush_disk when changing device size. 2011-02-24 17:25:47 +11:00
hd.c block: remove wrappers for request type/flags 2010-08-07 18:17:56 +02:00
ida_cmd.h
ida_ioctl.h
Kconfig xen: separate out frontend xenbus 2011-01-05 16:29:17 -05:00
loop.c block: kill loop_mutex 2011-03-03 11:53:25 -05:00
Makefile drivers/block/Makefile: replace the use of <module>-objs with <module>-y 2011-01-19 08:25:02 -07:00
mg_disk.c block: switch s390 tape_block and mg_disk to elevator_change() 2010-08-23 14:02:44 +02:00
nbd.c nbd: remove module-level ioctl mutex 2011-02-11 16:12:20 -08:00
osdblk.c block: remove spurious uses of REQ_HARDBARRIER 2010-09-10 12:35:36 +02:00
pktcdvd.c block: make blkdev_get/put() handle exclusive access 2010-11-13 11:55:17 +01:00
ps3disk.c Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block 2010-10-22 17:07:18 -07:00
ps3vram.c
rbd_types.h rbd: introduce rados block device (rbd), based on libceph 2010-10-20 15:38:13 -07:00
rbd.c rbd: fix cleanup when trying to mount inexistent image 2011-01-12 15:15:18 -08:00
smart1,2.h
sunvdc.c
swim3.c block: autoconvert trivial BKL users to private mutex 2010-10-05 15:01:10 +02:00
swim_asm.S
swim.c block: autoconvert trivial BKL users to private mutex 2010-10-05 15:01:10 +02:00
sx8.c
ub.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 2010-10-22 20:30:48 -07:00
umem.c block: unify flags for struct bio and struct request 2010-08-07 18:20:39 +02:00
umem.h
viodasd.c block: autoconvert trivial BKL users to private mutex 2010-10-05 15:01:10 +02:00
virtio_blk.c Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block 2010-10-22 17:07:18 -07:00
xd.c block: autoconvert trivial BKL users to private mutex 2010-10-05 15:01:10 +02:00
xd.h
xen-blkfront.c Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2011-01-07 16:58:04 -08:00
xsysace.c Merge branch 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6 2010-10-25 08:19:14 -07:00
z2ram.c drivers/block/z2ram.c: correct printing of sector_t 2010-10-28 06:15:26 -06:00