9c2e08c592
Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
135 lines
2.9 KiB
C
135 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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const 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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