fs/pstore/pmsg.c

Source file repositories/reference/linux-study-clean/fs/pstore/pmsg.c

File Facts

System
Linux kernel
Corpus path
fs/pstore/pmsg.c
Extension
.c
Size
1958 bytes
Lines
95
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: operation-table or driver-model contract
Status
pattern implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

static const struct file_operations pmsg_fops = {
	.owner		= THIS_MODULE,
	.llseek		= noop_llseek,
	.write		= write_pmsg,
};

static struct class *pmsg_class;
static int pmsg_major;
#define PMSG_NAME "pmsg"
#undef pr_fmt
#define pr_fmt(fmt) PMSG_NAME ": " fmt

static char *pmsg_devnode(const struct device *dev, umode_t *mode)
{
	if (mode)
		*mode = 0220;
	return NULL;
}

void pstore_register_pmsg(void)
{
	struct device *pmsg_device;

	pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops);
	if (pmsg_major < 0) {
		pr_err("register_chrdev failed\n");
		goto err;
	}

	pmsg_class = class_create(PMSG_NAME);
	if (IS_ERR(pmsg_class)) {
		pr_err("device class file already in use\n");
		goto err_class;
	}
	pmsg_class->devnode = pmsg_devnode;

	pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0),
					NULL, "%s%d", PMSG_NAME, 0);
	if (IS_ERR(pmsg_device)) {
		pr_err("failed to create device\n");
		goto err_device;
	}
	return;

err_device:
	class_destroy(pmsg_class);
err_class:
	unregister_chrdev(pmsg_major, PMSG_NAME);
err:
	return;
}

void pstore_unregister_pmsg(void)
{
	device_destroy(pmsg_class, MKDEV(pmsg_major, 0));
	class_destroy(pmsg_class);
	unregister_chrdev(pmsg_major, PMSG_NAME);
}

Annotation

Implementation Notes