Currently i_cdev reference to a character device isn't accounted in the reference count of the character device. This then requires us to track all references through a list of all inodes referencing a character device which is somewhat clumsy and requires list_head in each inode in the system.
So make i_cdev a reference like any other. Reviewed-by: Christoph Hellwig <[email protected]> Signed-off-by: Jan Kara <[email protected]> --- fs/char_dev.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/char_dev.c b/fs/char_dev.c index f77f7702fabe..518b3016ab92 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -388,12 +388,13 @@ static int chrdev_open(struct inode *inode, struct file *filp) we dropped the lock. */ p = inode->i_cdev; if (!p) { + /* Use reference from kobj_lookup for i_cdev ref */ inode->i_cdev = p = new; list_add(&inode->i_devices, &p->list); new = NULL; - } else if (!cdev_get(p)) - ret = -ENXIO; - } else if (!cdev_get(p)) + } + } + if (!cdev_get(p)) ret = -ENXIO; spin_unlock(&cdev_lock); cdev_put(new); @@ -421,10 +422,15 @@ static int chrdev_open(struct inode *inode, struct file *filp) void cd_forget(struct inode *inode) { + struct cdev *to_put; + spin_lock(&cdev_lock); list_del_init(&inode->i_devices); + to_put = inode->i_cdev; inode->i_cdev = NULL; spin_unlock(&cdev_lock); + if (to_put) + cdev_put(to_put); } static void cdev_purge(struct cdev *cdev) -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
