USB: EHCI: remove PCI assumption
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / char / raw.c
blob8756ab0daa8b3123bb4937dc128920fa0471e130
1 /*
2 * linux/drivers/char/raw.c
4 * Front-end raw character devices. These can be bound to any block
5 * devices to provide genuine Unix raw character device semantics.
7 * We reserve minor number 0 for a control interface. ioctl()s on this
8 * device are used to bind the other minor numbers to block devices.
9 */
11 #include <linux/init.h>
12 #include <linux/fs.h>
13 #include <linux/major.h>
14 #include <linux/blkdev.h>
15 #include <linux/module.h>
16 #include <linux/raw.h>
17 #include <linux/capability.h>
18 #include <linux/uio.h>
19 #include <linux/cdev.h>
20 #include <linux/device.h>
21 #include <linux/mutex.h>
22 #include <linux/smp_lock.h>
23 #include <linux/gfp.h>
25 #include <asm/uaccess.h>
27 struct raw_device_data {
28 struct block_device *binding;
29 int inuse;
32 static struct class *raw_class;
33 static struct raw_device_data raw_devices[MAX_RAW_MINORS];
34 static DEFINE_MUTEX(raw_mutex);
35 static const struct file_operations raw_ctl_fops; /* forward declaration */
38 * Open/close code for raw IO.
40 * We just rewrite the i_mapping for the /dev/raw/rawN file descriptor to
41 * point at the blockdev's address_space and set the file handle to use
42 * O_DIRECT.
44 * Set the device's soft blocksize to the minimum possible. This gives the
45 * finest possible alignment and has no adverse impact on performance.
47 static int raw_open(struct inode *inode, struct file *filp)
49 const int minor = iminor(inode);
50 struct block_device *bdev;
51 int err;
53 if (minor == 0) { /* It is the control device */
54 filp->f_op = &raw_ctl_fops;
55 return 0;
58 lock_kernel();
59 mutex_lock(&raw_mutex);
62 * All we need to do on open is check that the device is bound.
64 bdev = raw_devices[minor].binding;
65 err = -ENODEV;
66 if (!bdev)
67 goto out;
68 igrab(bdev->bd_inode);
69 err = blkdev_get(bdev, filp->f_mode);
70 if (err)
71 goto out;
72 err = bd_claim(bdev, raw_open);
73 if (err)
74 goto out1;
75 err = set_blocksize(bdev, bdev_logical_block_size(bdev));
76 if (err)
77 goto out2;
78 filp->f_flags |= O_DIRECT;
79 filp->f_mapping = bdev->bd_inode->i_mapping;
80 if (++raw_devices[minor].inuse == 1)
81 filp->f_path.dentry->d_inode->i_mapping =
82 bdev->bd_inode->i_mapping;
83 filp->private_data = bdev;
84 mutex_unlock(&raw_mutex);
85 unlock_kernel();
86 return 0;
88 out2:
89 bd_release(bdev);
90 out1:
91 blkdev_put(bdev, filp->f_mode);
92 out:
93 mutex_unlock(&raw_mutex);
94 unlock_kernel();
95 return err;
99 * When the final fd which refers to this character-special node is closed, we
100 * make its ->mapping point back at its own i_data.
102 static int raw_release(struct inode *inode, struct file *filp)
104 const int minor= iminor(inode);
105 struct block_device *bdev;
107 mutex_lock(&raw_mutex);
108 bdev = raw_devices[minor].binding;
109 if (--raw_devices[minor].inuse == 0) {
110 /* Here inode->i_mapping == bdev->bd_inode->i_mapping */
111 inode->i_mapping = &inode->i_data;
112 inode->i_mapping->backing_dev_info = &default_backing_dev_info;
114 mutex_unlock(&raw_mutex);
116 bd_release(bdev);
117 blkdev_put(bdev, filp->f_mode);
118 return 0;
122 * Forward ioctls to the underlying block device.
124 static int
125 raw_ioctl(struct inode *inode, struct file *filp,
126 unsigned int command, unsigned long arg)
128 struct block_device *bdev = filp->private_data;
130 return blkdev_ioctl(bdev, 0, command, arg);
133 static void bind_device(struct raw_config_request *rq)
135 device_destroy(raw_class, MKDEV(RAW_MAJOR, rq->raw_minor));
136 device_create(raw_class, NULL, MKDEV(RAW_MAJOR, rq->raw_minor), NULL,
137 "raw%d", rq->raw_minor);
141 * Deal with ioctls against the raw-device control interface, to bind
142 * and unbind other raw devices.
144 static int raw_ctl_ioctl(struct inode *inode, struct file *filp,
145 unsigned int command, unsigned long arg)
147 struct raw_config_request rq;
148 struct raw_device_data *rawdev;
149 int err = 0;
151 switch (command) {
152 case RAW_SETBIND:
153 case RAW_GETBIND:
155 /* First, find out which raw minor we want */
157 if (copy_from_user(&rq, (void __user *) arg, sizeof(rq))) {
158 err = -EFAULT;
159 goto out;
162 if (rq.raw_minor <= 0 || rq.raw_minor >= MAX_RAW_MINORS) {
163 err = -EINVAL;
164 goto out;
166 rawdev = &raw_devices[rq.raw_minor];
168 if (command == RAW_SETBIND) {
169 dev_t dev;
172 * This is like making block devices, so demand the
173 * same capability
175 if (!capable(CAP_SYS_ADMIN)) {
176 err = -EPERM;
177 goto out;
181 * For now, we don't need to check that the underlying
182 * block device is present or not: we can do that when
183 * the raw device is opened. Just check that the
184 * major/minor numbers make sense.
187 dev = MKDEV(rq.block_major, rq.block_minor);
188 if ((rq.block_major == 0 && rq.block_minor != 0) ||
189 MAJOR(dev) != rq.block_major ||
190 MINOR(dev) != rq.block_minor) {
191 err = -EINVAL;
192 goto out;
195 mutex_lock(&raw_mutex);
196 if (rawdev->inuse) {
197 mutex_unlock(&raw_mutex);
198 err = -EBUSY;
199 goto out;
201 if (rawdev->binding) {
202 bdput(rawdev->binding);
203 module_put(THIS_MODULE);
205 if (rq.block_major == 0 && rq.block_minor == 0) {
206 /* unbind */
207 rawdev->binding = NULL;
208 device_destroy(raw_class,
209 MKDEV(RAW_MAJOR, rq.raw_minor));
210 } else {
211 rawdev->binding = bdget(dev);
212 if (rawdev->binding == NULL)
213 err = -ENOMEM;
214 else {
215 __module_get(THIS_MODULE);
216 bind_device(&rq);
219 mutex_unlock(&raw_mutex);
220 } else {
221 struct block_device *bdev;
223 mutex_lock(&raw_mutex);
224 bdev = rawdev->binding;
225 if (bdev) {
226 rq.block_major = MAJOR(bdev->bd_dev);
227 rq.block_minor = MINOR(bdev->bd_dev);
228 } else {
229 rq.block_major = rq.block_minor = 0;
231 mutex_unlock(&raw_mutex);
232 if (copy_to_user((void __user *)arg, &rq, sizeof(rq))) {
233 err = -EFAULT;
234 goto out;
237 break;
238 default:
239 err = -EINVAL;
240 break;
242 out:
243 return err;
246 static const struct file_operations raw_fops = {
247 .read = do_sync_read,
248 .aio_read = generic_file_aio_read,
249 .write = do_sync_write,
250 .aio_write = blkdev_aio_write,
251 .fsync = blkdev_fsync,
252 .open = raw_open,
253 .release= raw_release,
254 .ioctl = raw_ioctl,
255 .owner = THIS_MODULE,
258 static const struct file_operations raw_ctl_fops = {
259 .ioctl = raw_ctl_ioctl,
260 .open = raw_open,
261 .owner = THIS_MODULE,
264 static struct cdev raw_cdev;
266 static char *raw_devnode(struct device *dev, mode_t *mode)
268 return kasprintf(GFP_KERNEL, "raw/%s", dev_name(dev));
271 static int __init raw_init(void)
273 dev_t dev = MKDEV(RAW_MAJOR, 0);
274 int ret;
276 ret = register_chrdev_region(dev, MAX_RAW_MINORS, "raw");
277 if (ret)
278 goto error;
280 cdev_init(&raw_cdev, &raw_fops);
281 ret = cdev_add(&raw_cdev, dev, MAX_RAW_MINORS);
282 if (ret) {
283 kobject_put(&raw_cdev.kobj);
284 goto error_region;
287 raw_class = class_create(THIS_MODULE, "raw");
288 if (IS_ERR(raw_class)) {
289 printk(KERN_ERR "Error creating raw class.\n");
290 cdev_del(&raw_cdev);
291 ret = PTR_ERR(raw_class);
292 goto error_region;
294 raw_class->devnode = raw_devnode;
295 device_create(raw_class, NULL, MKDEV(RAW_MAJOR, 0), NULL, "rawctl");
297 return 0;
299 error_region:
300 unregister_chrdev_region(dev, MAX_RAW_MINORS);
301 error:
302 return ret;
305 static void __exit raw_exit(void)
307 device_destroy(raw_class, MKDEV(RAW_MAJOR, 0));
308 class_destroy(raw_class);
309 cdev_del(&raw_cdev);
310 unregister_chrdev_region(MKDEV(RAW_MAJOR, 0), MAX_RAW_MINORS);
313 module_init(raw_init);
314 module_exit(raw_exit);
315 MODULE_LICENSE("GPL");