raw: don't keep unopened block device around

Turn binding into a normal dev_t as the struct block device doesn't
buy us anything and use blkdev_open_by_dev to actually open it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index ccf5bd5..5d52a1f 100644 (file)
--- a/drivers/char/raw.c
+++ b/drivers/char/raw.c
@@ -28,7 +28,8 @@
 #include <linux/uaccess.h>
 
 struct raw_device_data {
-       struct block_device *binding;
+       dev_t binding;
+       struct block_device *bdev;
        int inuse;
 };
 
@@ -73,14 +74,15 @@ static int raw_open(struct inode *inode, struct file *filp)
        /*
         * All we need to do on open is check that the device is bound.
         */
-       bdev = raw_devices[minor].binding;
        err = -ENODEV;
-       if (!bdev)
+       if (!raw_devices[minor].binding)
                goto out;
-       bdgrab(bdev);
-       err = blkdev_get(bdev, filp->f_mode | FMODE_EXCL, raw_open);
-       if (err)
+       bdev = blkdev_get_by_dev(raw_devices[minor].binding,
+                                filp->f_mode | FMODE_EXCL, raw_open);
+       if (IS_ERR(bdev)) {
+               err = PTR_ERR(bdev);
                goto out;
+       }
        err = set_blocksize(bdev, bdev_logical_block_size(bdev));
        if (err)
                goto out1;
@@ -90,6 +92,7 @@ static int raw_open(struct inode *inode, struct file *filp)
                file_inode(filp)->i_mapping =
                        bdev->bd_inode->i_mapping;
        filp->private_data = bdev;
+       raw_devices[minor].bdev = bdev;
        mutex_unlock(&raw_mutex);
        return 0;
 
@@ -110,7 +113,7 @@ static int raw_release(struct inode *inode, struct file *filp)
        struct block_device *bdev;
 
        mutex_lock(&raw_mutex);
-       bdev = raw_devices[minor].binding;
+       bdev = raw_devices[minor].bdev;
        if (--raw_devices[minor].inuse == 0)
                /* Here  inode->i_mapping == bdev->bd_inode->i_mapping  */
                inode->i_mapping = &inode->i_data;
@@ -133,6 +136,7 @@ raw_ioctl(struct file *filp, unsigned int command, unsigned long arg)
 static int bind_set(int number, u64 major, u64 minor)
 {
        dev_t dev = MKDEV(major, minor);
+       dev_t raw = MKDEV(RAW_MAJOR, number);
        struct raw_device_data *rawdev;
        int err = 0;
 
@@ -166,25 +170,17 @@ static int bind_set(int number, u64 major, u64 minor)
                mutex_unlock(&raw_mutex);
                return -EBUSY;
        }
-       if (rawdev->binding) {
-               bdput(rawdev->binding);
+       if (rawdev->binding)
                module_put(THIS_MODULE);
-       }
+
+       rawdev->binding = dev;
        if (!dev) {
                /* unbind */
-               rawdev->binding = NULL;
-               device_destroy(raw_class, MKDEV(RAW_MAJOR, number));
+               device_destroy(raw_class, raw);
        } else {
-               rawdev->binding = bdget(dev);
-               if (rawdev->binding == NULL) {
-                       err = -ENOMEM;
-               } else {
-                       dev_t raw = MKDEV(RAW_MAJOR, number);
-                       __module_get(THIS_MODULE);
-                       device_destroy(raw_class, raw);
-                       device_create(raw_class, NULL, raw, NULL,
-                                     "raw%d", number);
-               }
+               __module_get(THIS_MODULE);
+               device_destroy(raw_class, raw);
+               device_create(raw_class, NULL, raw, NULL, "raw%d", number);
        }
        mutex_unlock(&raw_mutex);
        return err;
@@ -192,18 +188,9 @@ static int bind_set(int number, u64 major, u64 minor)
 
 static int bind_get(int number, dev_t *dev)
 {
-       struct raw_device_data *rawdev;
-       struct block_device *bdev;
-
        if (number <= 0 || number >= max_raw_minors)
                return -EINVAL;
-
-       rawdev = &raw_devices[number];
-
-       mutex_lock(&raw_mutex);
-       bdev = rawdev->binding;
-       *dev = bdev ? bdev->bd_dev : 0;
-       mutex_unlock(&raw_mutex);
+       *dev = raw_devices[number].binding;
        return 0;
 }