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raw: don't keep unopened block device around

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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>
This commit is contained in:
Christoph Hellwig
2020-09-21 09:19:51 +02:00
committed by Jens Axboe
parent 0fc66c9d63
commit 5a56ad7882
1 changed files with 19 additions and 32 deletions
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51
drivers/char/raw.c
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@@ -28,7 +28,8 @@
#include <linux/uaccess.h> #include <linux/uaccess.h>
struct raw_device_data { struct raw_device_data {
struct block_device *binding; dev_t binding;
struct block_device *bdev;
int inuse; 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. * All we need to do on open is check that the device is bound.
*/ */
bdev = raw_devices[minor].binding;
err = -ENODEV; err = -ENODEV;
if (!bdev) if (!raw_devices[minor].binding)
goto out; goto out;
bdgrab(bdev); bdev = blkdev_get_by_dev(raw_devices[minor].binding,
err = blkdev_get(bdev, filp->f_mode | FMODE_EXCL, raw_open); filp->f_mode | FMODE_EXCL, raw_open);
if (err) if (IS_ERR(bdev)) {
err = PTR_ERR(bdev);
goto out; goto out;
}
err = set_blocksize(bdev, bdev_logical_block_size(bdev)); err = set_blocksize(bdev, bdev_logical_block_size(bdev));
if (err) if (err)
goto out1; goto out1;
@@ -90,6 +92,7 @@ static int raw_open(struct inode *inode, struct file *filp)
file_inode(filp)->i_mapping = file_inode(filp)->i_mapping =
bdev->bd_inode->i_mapping; bdev->bd_inode->i_mapping;
filp->private_data = bdev; filp->private_data = bdev;
raw_devices[minor].bdev = bdev;
mutex_unlock(&raw_mutex); mutex_unlock(&raw_mutex);
return 0; return 0;
@@ -110,7 +113,7 @@ static int raw_release(struct inode *inode, struct file *filp)
struct block_device *bdev; struct block_device *bdev;
mutex_lock(&raw_mutex); mutex_lock(&raw_mutex);
bdev = raw_devices[minor].binding; bdev = raw_devices[minor].bdev;
if (--raw_devices[minor].inuse == 0) if (--raw_devices[minor].inuse == 0)
/* Here inode->i_mapping == bdev->bd_inode->i_mapping */ /* Here inode->i_mapping == bdev->bd_inode->i_mapping */
inode->i_mapping = &inode->i_data; 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) static int bind_set(int number, u64 major, u64 minor)
{ {
dev_t dev = MKDEV(major, minor); dev_t dev = MKDEV(major, minor);
dev_t raw = MKDEV(RAW_MAJOR, number);
struct raw_device_data *rawdev; struct raw_device_data *rawdev;
int err = 0; int err = 0;
@@ -166,25 +170,17 @@ static int bind_set(int number, u64 major, u64 minor)
mutex_unlock(&raw_mutex); mutex_unlock(&raw_mutex);
return -EBUSY; return -EBUSY;
} }
if (rawdev->binding) { if (rawdev->binding)
bdput(rawdev->binding);
module_put(THIS_MODULE); module_put(THIS_MODULE);
}
rawdev->binding = dev;
if (!dev) { if (!dev) {
/* unbind */ /* unbind */
rawdev->binding = NULL; device_destroy(raw_class, raw);
device_destroy(raw_class, MKDEV(RAW_MAJOR, number));
} else { } else {
rawdev->binding = bdget(dev); __module_get(THIS_MODULE);
if (rawdev->binding == NULL) { device_destroy(raw_class, raw);
err = -ENOMEM; device_create(raw_class, NULL, raw, NULL, "raw%d", number);
} 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);
}
} }
mutex_unlock(&raw_mutex); mutex_unlock(&raw_mutex);
return err; 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) 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) if (number <= 0 || number >= max_raw_minors)
return -EINVAL; return -EINVAL;
*dev = raw_devices[number].binding;
rawdev = &raw_devices[number];
mutex_lock(&raw_mutex);
bdev = rawdev->binding;
*dev = bdev ? bdev->bd_dev : 0;
mutex_unlock(&raw_mutex);
return 0; return 0;
} }