Re: [patch] lockdep: annotate pktcdvd natural device hierarchy

Peter Osterlund
2006-07-15T10:58:52Z

Laurent Riffard <laurent.riffard@free.fr> writes:

> Le 15.07.2006 09:04, Arjan van de Ven a écrit :
>
> Thanks Arjan, this seems to solve the initial issue of this thread,
> which was "possible circular locking deadlock detected!" while
> doing "pktsetup dvd /dev/dvd".
>
> So here is the next step :-(. I'm now running 2.6.18-rc1-mm2 and I was able
> to successfully run:
> - modprobe ptkcdvd
> - pktsetup dvd /dev/dvd
>
> Then I inserted a UDF-formatted CD-RW in the CD/DVD burner and I typed
> this command :
> - mount -oro -tauto /dev/pktcdvd/dvd /mnt/cdrom
> The following happened :
>
> pktcdvd: writer pktcdvd0 mapped to hdc
>
> =============================================
> [ INFO: possible recursive locking detected ]
> ---------------------------------------------

I got the same problem. This patch fixes it in my case. I'm not sure
if using the *_partition() functions is the right thing to do, but the
device mapper code is using those functions in similar situations.

drivers/block/pktcdvd.c | 12 ++++++------
fs/block_dev.c | 7 +++----
include/linux/fs.h | 1 +
3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index f87d1a8..ccded00 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -1922,7 +1922,7 @@ static int pkt_open_dev(struct pktcdvd_d
* so bdget() can't fail.
*/
bdget(pd->bdev->bd_dev);
- if ((ret = blkdev_get(pd->bdev, FMODE_READ, O_RDONLY)))
+ if ((ret = blkdev_get_partition(pd->bdev, FMODE_READ, O_RDONLY)))
goto out;

if ((ret = bd_claim(pd->bdev, pd)))
@@ -1971,7 +1971,7 @@ static int pkt_open_dev(struct pktcdvd_d
out_unclaim:
bd_release(pd->bdev);
out_putdev:
- blkdev_put(pd->bdev);
+ blkdev_put_partition(pd->bdev);
out:
return ret;
}
@@ -1989,7 +1989,7 @@ static void pkt_release_dev(struct pktcd

pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
bd_release(pd->bdev);
- blkdev_put(pd->bdev);
+ blkdev_put_partition(pd->bdev);

pkt_shrink_pktlist(pd);
}
@@ -2339,7 +2339,7 @@ static int pkt_new_dev(struct pktcdvd_de
bdev = bdget(dev);
if (!bdev)
return -ENOMEM;
- ret = blkdev_get(bdev, FMODE_READ, O_RDONLY | O_NONBLOCK);
+ ret = blkdev_get_partition(bdev, FMODE_READ, O_RDONLY | O_NONBLOCK);
if (ret)
return ret;

@@ -2368,7 +2368,7 @@ static int pkt_new_dev(struct pktcdvd_de
return 0;

out_mem:
- blkdev_put(bdev);
+ blkdev_put_partition(bdev);
/* This is safe: open() is still holding a reference. */
module_put(THIS_MODULE);
return ret;
@@ -2530,7 +2530,7 @@ static int pkt_remove_dev(struct pkt_ctr
if (!IS_ERR(pd->cdrw.thread))
kthread_stop(pd->cdrw.thread);

- blkdev_put(pd->bdev);
+ blkdev_put_partition(pd->bdev);

remove_proc_entry(pd->name, pkt_proc);
DPRINTK("pktcdvd: writer %s unmapped\n", pd->name);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b721bb6..642e9b2 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -822,9 +822,6 @@ struct block_device *open_by_devnum(dev_

EXPORT_SYMBOL(open_by_devnum);

-static int
-blkdev_get_partition(struct block_device *bdev, mode_t mode, unsigned flags);
-
struct block_device *open_partition_by_devnum(dev_t dev, unsigned mode)
{
struct block_device *bdev = bdget(dev);
@@ -1031,7 +1028,7 @@ blkdev_get_whole(struct block_device *bd
return do_open(bdev, &fake_file, BD_MUTEX_WHOLE);
}

-static int
+int
blkdev_get_partition(struct block_device *bdev, mode_t mode, unsigned flags)
{
/*
@@ -1050,6 +1047,8 @@ blkdev_get_partition(struct block_device
return do_open(bdev, &fake_file, BD_MUTEX_PARTITION);
}

+EXPORT_SYMBOL(blkdev_get_partition);
+
static int blkdev_open(struct inode * inode, struct file * filp)
{
struct block_device *bdev;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b9f1c18..10f8c56 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1455,6 +1455,7 @@ extern int ioctl_by_bdev(struct block_de
extern int blkdev_ioctl(struct block_device *, struct file *, unsigned, unsigned long);
extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
extern int blkdev_get(struct block_device *, mode_t, unsigned);
+extern int blkdev_get_partition(struct block_device *, mode_t, unsigned);
extern int blkdev_put(struct block_device *);
extern int blkdev_put_partition(struct block_device *);
extern int bd_claim(struct block_device *, void *);

--
Peter Osterlund - petero2@telia.com