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Update code to use misc_register()/misc_deregister()

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When ZPIOS was originally written it was designed to use the
device_create() and device_destroy() functions.  Unfortunately,
these functions changed considerably over the years making them
difficult to rely on.

As it turns out a better choice would have been to use the
misc_register()/misc_deregister() functions.  This interface
for registering character devices has remained stable, is simple,
and provides everything we need.

Therefore the code has been reworked to use this interface.  The
higher level ZFS code has always depended on these same interfaces
so this is also as a step towards minimizing our kernel dependencies.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2757
This commit is contained in:
Brian Behlendorf 2014-09-30 19:24:04 -04:00
parent e33045ee98
commit 60bba62814
2 changed files with 28 additions and 67 deletions
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2
include/zpios-ctl.h
View File

@ -42,8 +42,6 @@
#include <stdint.h>
#endif
#define ZPIOS_MAJOR 232 /* XXX - Arbitrary */
#define ZPIOS_MINORS 1
#define ZPIOS_NAME "zpios"
#define ZPIOS_DEV "/dev/zpios"

93
module/zpios/pios.c
View File

@ -35,12 +35,10 @@
#include <sys/dmu.h>
#include <sys/txg.h>
#include <sys/dsl_destroy.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>
#include "zpios-internal.h"
static spl_class *zpios_class;
static spl_device *zpios_device;
static char *zpios_tag = "zpios_tag";
static int
@ -928,12 +926,8 @@ cleanup:
static int
zpios_open(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
zpios_info_t *info;
if (minor >= ZPIOS_MINORS)
return (-ENXIO);
info = (zpios_info_t *)kmem_alloc(sizeof (*info), KM_SLEEP);
if (info == NULL)
return (-ENOMEM);
@ -956,12 +950,8 @@ zpios_open(struct inode *inode, struct file *file)
static int
zpios_release(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
zpios_info_t *info = (zpios_info_t *)file->private_data;
if (minor >= ZPIOS_MINORS)
return (-ENXIO);
ASSERT(info);
ASSERT(info->info_buffer);
@ -1143,16 +1133,12 @@ out_cmd:
static long
zpios_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
unsigned int minor = iminor(file->f_dentry->d_inode);
int rc = 0;
/* Ignore tty ioctls */
if ((cmd & 0xffffff00) == ((int)'T') << 8)
return (-ENOTTY);
if (minor >= ZPIOS_MINORS)
return (-ENXIO);
switch (cmd) {
case ZPIOS_CFG:
rc = zpios_ioctl_cfg(file, arg);
@ -1187,13 +1173,9 @@ static ssize_t
zpios_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
unsigned int minor = iminor(file->f_dentry->d_inode);
zpios_info_t *info = (zpios_info_t *)file->private_data;
int rc = 0;
if (minor >= ZPIOS_MINORS)
return (-ENXIO);
ASSERT(info);
ASSERT(info->info_buffer);
@ -1224,13 +1206,9 @@ out:
static ssize_t
zpios_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
unsigned int minor = iminor(file->f_dentry->d_inode);
zpios_info_t *info = (zpios_info_t *)file->private_data;
int rc = 0;
if (minor >= ZPIOS_MINORS)
return (-ENXIO);
ASSERT(info);
ASSERT(info->info_buffer);
@ -1258,13 +1236,9 @@ out:
static loff_t zpios_seek(struct file *file, loff_t offset, int origin)
{
unsigned int minor = iminor(file->f_dentry->d_inode);
zpios_info_t *info = (zpios_info_t *)file->private_data;
int rc = -EINVAL;
if (minor >= ZPIOS_MINORS)
return (-ENXIO);
ASSERT(info);
ASSERT(info->info_buffer);
@ -1292,7 +1266,6 @@ static loff_t zpios_seek(struct file *file, loff_t offset, int origin)
return (rc);
}
static struct cdev zpios_cdev;
static struct file_operations zpios_fops = {
.owner = THIS_MODULE,
.open = zpios_open,
@ -1306,55 +1279,45 @@ static struct file_operations zpios_fops = {
.llseek = zpios_seek,
};
static struct miscdevice zpios_misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = ZPIOS_NAME,
.fops = &zpios_fops,
};
#ifdef DEBUG
#define ZFS_DEBUG_STR " (DEBUG mode)"
#else
#define ZFS_DEBUG_STR ""
#endif
static int
zpios_init(void)
{
dev_t dev;
int rc;
int error;
dev = MKDEV(ZPIOS_MAJOR, 0);
if ((rc = register_chrdev_region(dev, ZPIOS_MINORS, ZPIOS_NAME)))
goto error;
/* Support for registering a character driver */
cdev_init(&zpios_cdev, &zpios_fops);
zpios_cdev.owner = THIS_MODULE;
kobject_set_name(&zpios_cdev.kobj, ZPIOS_NAME);
if ((rc = cdev_add(&zpios_cdev, dev, ZPIOS_MINORS))) {
printk(KERN_ERR "ZPIOS: Error adding cdev, %d\n", rc);
kobject_put(&zpios_cdev.kobj);
unregister_chrdev_region(dev, ZPIOS_MINORS);
goto error;
error = misc_register(&zpios_misc);
if (error) {
printk(KERN_INFO "ZPIOS: misc_register() failed %d\n", error);
} else {
printk(KERN_INFO "ZPIOS: Loaded module v%s-%s%s\n",
ZFS_META_VERSION, ZFS_META_RELEASE, ZFS_DEBUG_STR);
}
/* Support for udev make driver info available in sysfs */
zpios_class = spl_class_create(THIS_MODULE, ZPIOS_NAME);
if (IS_ERR(zpios_class)) {
rc = PTR_ERR(zpios_class);
printk(KERN_ERR "ZPIOS: Error creating zpios class, %d\n", rc);
cdev_del(&zpios_cdev);
unregister_chrdev_region(dev, ZPIOS_MINORS);
goto error;
}
zpios_device = spl_device_create(zpios_class, NULL,
dev, NULL, ZPIOS_NAME);
return (0);
error:
printk(KERN_ERR "ZPIOS: Error registering zpios device, %d\n", rc);
return (rc);
return (error);
}
static int
zpios_fini(void)
{
dev_t dev = MKDEV(ZPIOS_MAJOR, 0);
int error;
spl_device_destroy(zpios_class, zpios_device, dev);
spl_class_destroy(zpios_class);
cdev_del(&zpios_cdev);
unregister_chrdev_region(dev, ZPIOS_MINORS);
error = misc_deregister(&zpios_misc);
if (error)
printk(KERN_INFO "ZPIOS: misc_deregister() failed %d\n", error);
printk(KERN_INFO "ZPIOS: Unloaded module v%s-%s%s\n",
ZFS_META_VERSION, ZFS_META_RELEASE, ZFS_DEBUG_STR);
return (0);
}