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Fix character_device_create.c with missing cdev_del

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Ciro Santilli
2017-08-06 12:58:13 +01:00
parent f67d99ff24
commit a5b2038eab
1 changed files with 28 additions and 12 deletions
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40
kernel_module/character_device_create.c
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@@ -1,10 +1,7 @@
/* /*
Automatically create the device under /dev on insmod, and remove on rmmod. Automatically create the device under /dev on insmod, and remove on rmmod.
TODO: by itself works, but if I try to cat character_device.ko after removing this, that OOPS! https://stackoverflow.com/questions/5970595/how-to-create-a-device-node-from-the-init-module-code-of-a-linux-kernel-module
https://stackoverflow.com/questions/5970595/create-a-device-node-in-code/
https://stackoverflow.com/questions/5970595/how-to-create-a-device-node-from-the-init-module-code-of-a-linux-kernel-module/18594761#18594761
*/ */
#include <linux/cdev.h> #include <linux/cdev.h>
@@ -38,25 +35,44 @@ static const struct file_operations fops = {
.release = single_release, .release = single_release,
}; };
static void cleanup(int device_created)
{
if (device_created) {
device_destroy(myclass, major);
cdev_del(&mycdev);
}
if (myclass)
class_destroy(myclass);
if (major != -1)
unregister_chrdev_region(major, 1);
}
static int myinit(void) static int myinit(void)
{ {
int device_created = 0;
/* cat /proc/devices */ /* cat /proc/devices */
if (alloc_chrdev_region(&major, 0, 1, NAME "_proc")) { if (alloc_chrdev_region(&major, 0, 1, NAME "_proc") < 0)
}; goto error;
/* ls /sys/class */ /* ls /sys/class */
myclass = class_create(THIS_MODULE, NAME "_sys"); if ((myclass = class_create(THIS_MODULE, NAME "_sys")) == NULL)
goto error;
/* ls /dev/ */ /* ls /dev/ */
device_create(myclass, NULL, major, NULL, NAME "_dev"); if (device_create(myclass, NULL, major, NULL, NAME "_dev") == NULL)
goto error;
device_created = 1;
cdev_init(&mycdev, &fops); cdev_init(&mycdev, &fops);
cdev_add(&mycdev, major, 1); if (cdev_add(&mycdev, major, 1) == -1)
goto error;
return 0; return 0;
error:
cleanup(device_created);
return -1;
} }
static void myexit(void) static void myexit(void)
{ {
device_destroy(myclass, major); cleanup(1);
class_destroy(myclass);
unregister_chrdev_region(major, 1);
} }
module_init(myinit) module_init(myinit)