Commit d45ac4fa authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by James Bottomley
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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: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent 0e4ff797

block/bsg.c

+13 −6
Original line number Diff line number Diff line
@@ -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);

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