25a2001a28
Without this patch register_tape_dev() will always fail, but might return a value that is not an error number. This will lead to accesses to already freed memory areas... Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
134 lines
2.9 KiB
C
134 lines
2.9 KiB
C
/*
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* (C) Copyright IBM Corp. 2004
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* tape_class.c
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*
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* Tape class device support
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*
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* Author: Stefan Bader <shbader@de.ibm.com>
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* Based on simple class device code by Greg K-H
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*/
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#include "tape_class.h"
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MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
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MODULE_DESCRIPTION(
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"(C) Copyright IBM Corp. 2004 All Rights Reserved.\n"
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"tape_class.c"
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);
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MODULE_LICENSE("GPL");
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static struct class *tape_class;
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/*
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* Register a tape device and return a pointer to the cdev structure.
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*
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* device
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* The pointer to the struct device of the physical (base) device.
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* drivername
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* The pointer to the drivers name for it's character devices.
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* dev
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* The intended major/minor number. The major number may be 0 to
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* get a dynamic major number.
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* fops
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* The pointer to the drivers file operations for the tape device.
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* devname
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* The pointer to the name of the character device.
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*/
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struct tape_class_device *register_tape_dev(
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struct device * device,
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dev_t dev,
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struct file_operations *fops,
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char * device_name,
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char * mode_name)
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{
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struct tape_class_device * tcd;
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int rc;
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char * s;
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tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
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if (!tcd)
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return ERR_PTR(-ENOMEM);
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strncpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
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for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
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*s = '!';
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strncpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
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for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
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*s = '!';
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tcd->char_device = cdev_alloc();
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if (!tcd->char_device) {
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rc = -ENOMEM;
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goto fail_with_tcd;
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}
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tcd->char_device->owner = fops->owner;
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tcd->char_device->ops = fops;
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tcd->char_device->dev = dev;
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rc = cdev_add(tcd->char_device, tcd->char_device->dev, 1);
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if (rc)
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goto fail_with_cdev;
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tcd->class_device = class_device_create(
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tape_class,
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NULL,
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tcd->char_device->dev,
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device,
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"%s", tcd->device_name
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);
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rc = IS_ERR(tcd->class_device) ? PTR_ERR(tcd->class_device) : 0;
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if (rc)
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goto fail_with_cdev;
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rc = sysfs_create_link(
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&device->kobj,
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&tcd->class_device->kobj,
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tcd->mode_name
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);
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if (rc)
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goto fail_with_class_device;
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return tcd;
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fail_with_class_device:
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class_device_destroy(tape_class, tcd->char_device->dev);
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fail_with_cdev:
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cdev_del(tcd->char_device);
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fail_with_tcd:
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kfree(tcd);
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return ERR_PTR(rc);
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}
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EXPORT_SYMBOL(register_tape_dev);
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void unregister_tape_dev(struct tape_class_device *tcd)
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{
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if (tcd != NULL && !IS_ERR(tcd)) {
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sysfs_remove_link(
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&tcd->class_device->dev->kobj,
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tcd->mode_name
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);
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class_device_destroy(tape_class, tcd->char_device->dev);
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cdev_del(tcd->char_device);
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kfree(tcd);
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}
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}
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EXPORT_SYMBOL(unregister_tape_dev);
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static int __init tape_init(void)
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{
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tape_class = class_create(THIS_MODULE, "tape390");
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return 0;
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}
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static void __exit tape_exit(void)
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{
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class_destroy(tape_class);
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tape_class = NULL;
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}
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postcore_initcall(tape_init);
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module_exit(tape_exit);
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