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[SCSI] bsg: takes a ref to struct device in fops->open 

bsg_register_queue() takes a ref to struct device that a caller
passes. For example, bsg takes a ref to the sdev_gendev for scsi
devices. However, bsg doesn't inrease the refcount in fops->open. So
while an application opens a bsg device, the scsi device that the bsg
device holds can go away (bsg also takes a ref to a queue, but it
doesn't prevent the device from going away).

With this patch, bsg increases the refcount of struct device in
fops->open and decreases it in fops->release.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
FUJITA Tomonori 2008-03-31 10:03:38 +09:00 committed by James Bottomley
parent 0e4ff797d7
commit d45ac4fa8f
1 changed files with 13 additions and 6 deletions
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19
block/bsg.c
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@ -705,6 +705,7 @@ static struct bsg_device *bsg_alloc_device(void)
static int bsg_put_device(struct bsg_device *bd)
{
int ret = 0;
struct device *dev = bd->queue->bsg_dev.dev;
mutex_lock(&bsg_mutex);
@ -730,6 +731,7 @@ static int bsg_put_device(struct bsg_device *bd)
kfree(bd);
out:
mutex_unlock(&bsg_mutex);
put_device(dev);
return ret;
}
@ -789,21 +791,27 @@ static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
struct bsg_device *bd;
struct bsg_class_device *bcd;
bd = __bsg_get_device(iminor(inode));
if (bd)
return bd;
/*
* find the class device
*/
mutex_lock(&bsg_mutex);
bcd = idr_find(&bsg_minor_idr, iminor(inode));
if (bcd)
get_device(bcd->dev);
mutex_unlock(&bsg_mutex);
if (!bcd)
return ERR_PTR(-ENODEV);
return bsg_add_device(inode, bcd->queue, file);
bd = __bsg_get_device(iminor(inode));
if (bd)
return bd;
bd = bsg_add_device(inode, bcd->queue, file);
if (IS_ERR(bd))
put_device(bcd->dev);
return bd;
}
static int bsg_open(struct inode *inode, struct file *file)
@ -942,7 +950,6 @@ void bsg_unregister_queue(struct request_queue *q)
class_device_unregister(bcd->class_dev);
put_device(bcd->dev);
bcd->class_dev = NULL;
bcd->dev = NULL;
mutex_unlock(&bsg_mutex);
}
EXPORT_SYMBOL_GPL(bsg_unregister_queue);