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authorLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 11:55:42 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 11:55:42 -0700
commit09c0dc68625c06f5b1e786aad0d5369b592179e6 (patch)
tree19fd06de08792a4c07ee8b61e5615ee35e8ccec0
parent2a2ed2db353d949c06b6ef8b6913f65b39111eab (diff)
Revert "[PATCH] kthread: update loop.c to use kthread"
This reverts commit c7b2eff059fcc2d1b7085ee3d84b79fd657a537b. 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 <torvalds@osdl.org>
-rw-r--r--drivers/block/loop.c24
-rw-r--r--include/linux/loop.h2
2 files changed, 14 insertions, 12 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 9dc294a74953..3c74ea729fc7 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -74,7 +74,6 @@
#include <linux/completion.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
-#include <linux/kthread.h>
#include <asm/uaccess.h>
@@ -579,6 +578,8 @@ static int loop_thread(void *data)
struct loop_device *lo = data;
struct bio *bio;
+ daemonize("loop%d", lo->lo_number);
+
/*
* loop can be used in an encrypted device,
* hence, it mustn't be stopped at all
@@ -591,6 +592,11 @@ static int loop_thread(void *data)
lo->lo_state = Lo_bound;
lo->lo_pending = 1;
+ /*
+ * complete it, we are running
+ */
+ complete(&lo->lo_done);
+
for (;;) {
int pending;
@@ -623,6 +629,7 @@ static int loop_thread(void *data)
break;
}
+ complete(&lo->lo_done);
return 0;
}
@@ -739,7 +746,6 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
unsigned lo_blocksize;
int lo_flags = 0;
int error;
- struct task_struct *tsk;
loff_t size;
/* This is safe, since we have a reference from open(). */
@@ -833,11 +839,10 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
set_blocksize(bdev, lo_blocksize);
- tsk = kthread_run(loop_thread, lo, "loop%d", lo->lo_number);
- if (IS_ERR(tsk)) {
- error = PTR_ERR(tsk);
+ error = kernel_thread(loop_thread, lo, CLONE_KERNEL);
+ if (error < 0)
goto out_putf;
- }
+ wait_for_completion(&lo->lo_done);
return 0;
out_putf:
@@ -893,9 +898,6 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
if (lo->lo_state != Lo_bound)
return -ENXIO;
- if (!lo->lo_thread)
- return -EINVAL;
-
if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */
return -EBUSY;
@@ -909,7 +911,7 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
complete(&lo->lo_bh_done);
spin_unlock_irq(&lo->lo_lock);
- kthread_stop(lo->lo_thread);
+ wait_for_completion(&lo->lo_done);
lo->lo_backing_file = NULL;
@@ -922,7 +924,6 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
lo->lo_sizelimit = 0;
lo->lo_encrypt_key_size = 0;
lo->lo_flags = 0;
- lo->lo_thread = NULL;
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
memset(lo->lo_file_name, 0, LO_NAME_SIZE);
@@ -1287,6 +1288,7 @@ static int __init loop_init(void)
if (!lo->lo_queue)
goto out_mem4;
mutex_init(&lo->lo_ctl_mutex);
+ init_completion(&lo->lo_done);
init_completion(&lo->lo_bh_done);
lo->lo_number = i;
spin_lock_init(&lo->lo_lock);
diff --git a/include/linux/loop.h b/include/linux/loop.h
index bf3d2345ce99..e76c7611d6cc 100644
--- a/include/linux/loop.h
+++ b/include/linux/loop.h
@@ -59,7 +59,7 @@ struct loop_device {
struct bio *lo_bio;
struct bio *lo_biotail;
int lo_state;
- struct task_struct *lo_thread;
+ struct completion lo_done;
struct completion lo_bh_done;
struct mutex lo_ctl_mutex;
int lo_pending;