Revert "[PATCH] kthread: update loop.c to use kthread"
This reverts commit c7b2eff0 . Hugh Dickins explains: "It seems too little tested: "losetup -d /dev/loop0" fails with EINVAL because nothing sets lo_thread; but even when you patch loop_thread() to set lo->lo_thread = current, it can't survive more than a few dozen iterations of the loop below (with a tmpfs mounted on /tst): j=0 cp /dev/zero /tst while : do let j=j+1 echo "Doing pass $j" losetup /dev/loop0 /tst/zero mkfs -t ext2 -b 1024 /dev/loop0 >/dev/null 2>&1 mount -t ext2 /dev/loop0 /mnt umount /mnt losetup -d /dev/loop0 done it collapses with failed ioctl then BUG_ON(!bio). I think the original lo_done completion was more subtle and safe than the kthread conversion has allowed for." Signed-off-by: Linus Torvalds <firstname.lastname@example.org>