X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=fs%2Fchar_dev.c;h=d6db933df2b27ce43c0fe31d6e35bb0968598891;hp=038674aa88a72c09a88388ee7cf1b54839675052;hb=4434ade8c9334a3ab975d8993de456f06841899e;hpb=922f9cfa79b52c85b6002d96cb0eefd13437c58c diff --git a/fs/char_dev.c b/fs/char_dev.c index 038674a..d6db933 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -13,7 +13,6 @@ #include #include #include -#include #include #include @@ -22,9 +21,6 @@ #include #include -#ifdef CONFIG_KMOD -#include -#endif #include "internal.h" /* @@ -35,6 +31,7 @@ * - no readahead or I/O queue unplugging required */ struct backing_dev_info directly_mappable_cdev_bdi = { + .name = "char", .capabilities = ( #ifdef CONFIG_MMU /* permit private copies of the data to be taken */ @@ -55,7 +52,6 @@ static struct char_device_struct { unsigned int baseminor; int minorct; char name[64]; - struct file_operations *fops; struct cdev *cdev; /* will die */ } *chrdevs[CHRDEV_MAJOR_HASH_SIZE]; @@ -124,7 +120,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor, cd->major = major; cd->baseminor = baseminor; cd->minorct = minorct; - strncpy(cd->name,name, 64); + strlcpy(cd->name, name, sizeof(cd->name)); i = major_to_index(major); @@ -242,8 +238,10 @@ int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, } /** - * register_chrdev() - Register a major number for character devices. + * __register_chrdev() - create and register a cdev occupying a range of minors * @major: major device number or 0 for dynamic allocation + * @baseminor: first of the requested range of minor numbers + * @count: the number of minor numbers required * @name: name of this range of devices * @fops: file operations associated with this devices * @@ -259,19 +257,16 @@ int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, * /dev. It only helps to keep track of the different owners of devices. If * your module name has only one type of devices it's ok to use e.g. the name * of the module here. - * - * This function registers a range of 256 minor numbers. The first minor number - * is 0. */ -int register_chrdev(unsigned int major, const char *name, - const struct file_operations *fops) +int __register_chrdev(unsigned int major, unsigned int baseminor, + unsigned int count, const char *name, + const struct file_operations *fops) { struct char_device_struct *cd; struct cdev *cdev; - char *s; int err = -ENOMEM; - cd = __register_chrdev_region(major, 0, 256, name); + cd = __register_chrdev_region(major, baseminor, count, name); if (IS_ERR(cd)) return PTR_ERR(cd); @@ -282,10 +277,8 @@ int register_chrdev(unsigned int major, const char *name, cdev->owner = fops->owner; cdev->ops = fops; kobject_set_name(&cdev->kobj, "%s", name); - for (s = strchr(kobject_name(&cdev->kobj),'/'); s; s = strchr(s, '/')) - *s = '!'; - err = cdev_add(cdev, MKDEV(cd->major, 0), 256); + err = cdev_add(cdev, MKDEV(cd->major, baseminor), count); if (err) goto out; @@ -295,7 +288,7 @@ int register_chrdev(unsigned int major, const char *name, out: kobject_put(&cdev->kobj); out2: - kfree(__unregister_chrdev_region(cd->major, 0, 256)); + kfree(__unregister_chrdev_region(cd->major, baseminor, count)); return err; } @@ -321,10 +314,23 @@ void unregister_chrdev_region(dev_t from, unsigned count) } } -void unregister_chrdev(unsigned int major, const char *name) +/** + * __unregister_chrdev - unregister and destroy a cdev + * @major: major device number + * @baseminor: first of the range of minor numbers + * @count: the number of minor numbers this cdev is occupying + * @name: name of this range of devices + * + * Unregister and destroy the cdev occupying the region described by + * @major, @baseminor and @count. This function undoes what + * __register_chrdev() did. + */ +void __unregister_chrdev(unsigned int major, unsigned int baseminor, + unsigned int count, const char *name) { struct char_device_struct *cd; - cd = __unregister_chrdev_region(major, 0, 256); + + cd = __unregister_chrdev_region(major, baseminor, count); if (cd && cd->cdev) cdev_del(cd->cdev); kfree(cd); @@ -374,10 +380,11 @@ static int chrdev_open(struct inode *inode, struct file *filp) return -ENXIO; new = container_of(kobj, struct cdev, kobj); spin_lock(&cdev_lock); + /* Check i_cdev again in case somebody beat us to it while + we dropped the lock. */ p = inode->i_cdev; if (!p) { inode->i_cdev = p = new; - inode->i_cindex = idx; list_add(&inode->i_devices, &p->list); new = NULL; } else if (!cdev_get(p)) @@ -388,21 +395,37 @@ static int chrdev_open(struct inode *inode, struct file *filp) cdev_put(new); if (ret) return ret; + + ret = -ENXIO; filp->f_op = fops_get(p->ops); - if (!filp->f_op) { - cdev_put(p); - return -ENXIO; - } + if (!filp->f_op) + goto out_cdev_put; + if (filp->f_op->open) { - lock_kernel(); ret = filp->f_op->open(inode,filp); - unlock_kernel(); + if (ret) + goto out_cdev_put; } - if (ret) - cdev_put(p); + + return 0; + + out_cdev_put: + cdev_put(p); return ret; } +int cdev_index(struct inode *inode) +{ + int idx; + struct kobject *kobj; + + kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx); + if (!kobj) + return -1; + kobject_put(kobj); + return idx; +} + void cd_forget(struct inode *inode) { spin_lock(&cdev_lock); @@ -555,6 +578,7 @@ EXPORT_SYMBOL(cdev_init); EXPORT_SYMBOL(cdev_alloc); EXPORT_SYMBOL(cdev_del); EXPORT_SYMBOL(cdev_add); -EXPORT_SYMBOL(register_chrdev); -EXPORT_SYMBOL(unregister_chrdev); +EXPORT_SYMBOL(cdev_index); +EXPORT_SYMBOL(__register_chrdev); +EXPORT_SYMBOL(__unregister_chrdev); EXPORT_SYMBOL(directly_mappable_cdev_bdi);