From d45ac4fa8f277e1ec5acfb67ce5d6406555760cf Mon Sep 17 00:00:00 2001
From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Date: Mon, 31 Mar 2008 10:03:38 +0900
Subject: [PATCH] [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>
---
block/bsg.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/block/bsg.c b/block/bsg.c
index 8917c5174dc2..d8e0cb8dd6be 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -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);