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/*
* Hypervisor filesystem for Linux on s390 - debugfs interface
*
* Copyright (C) IBM Corp. 2010
* Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
*/
#include <linux/slab.h>
#include "hypfs.h"
static struct dentry *dbfs_dir;
static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f)
{
struct hypfs_dbfs_data *data;
data = kmalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return NULL;
kref_init(&data->kref);
data->dbfs_file = f;
return data;
}
static void hypfs_dbfs_data_free(struct kref *kref)
{
struct hypfs_dbfs_data *data;
data = container_of(kref, struct hypfs_dbfs_data, kref);
data->dbfs_file->data_free(data->buf_free_ptr);
kfree(data);
}
static void data_free_delayed(struct work_struct *work)
{
struct hypfs_dbfs_data *data;
struct hypfs_dbfs_file *df;
df = container_of(work, struct hypfs_dbfs_file, data_free_work.work);
mutex_lock(&df->lock);
data = df->data;
df->data = NULL;
mutex_unlock(&df->lock);
kref_put(&data->kref, hypfs_dbfs_data_free);
}
static ssize_t dbfs_read(struct file *file, char __user *buf,
size_t size, loff_t *ppos)
{
struct hypfs_dbfs_data *data;
struct hypfs_dbfs_file *df;
ssize_t rc;
if (*ppos != 0)
return 0;
df = file->f_path.dentry->d_inode->i_private;
mutex_lock(&df->lock);
if (!df->data) {
data = hypfs_dbfs_data_alloc(df);
if (!data) {
mutex_unlock(&df->lock);
return -ENOMEM;
}
rc = df->data_create(&data->buf, &data->buf_free_ptr,
&data->size);
if (rc) {
mutex_unlock(&df->lock);
kfree(data);
return rc;
}
df->data = data;
schedule_delayed_work(&df->data_free_work, HZ);
}
data = df->data;
kref_get(&data->kref);
mutex_unlock(&df->lock);
rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
kref_put(&data->kref, hypfs_dbfs_data_free);
return rc;
}
static const struct file_operations dbfs_ops = {
.read = dbfs_read,
.llseek = no_llseek,
};
int hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
{
df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df,
&dbfs_ops);
if (IS_ERR(df->dentry))
return PTR_ERR(df->dentry);
mutex_init(&df->lock);
INIT_DELAYED_WORK(&df->data_free_work, data_free_delayed);
return 0;
}
void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
{
debugfs_remove(df->dentry);
}
int hypfs_dbfs_init(void)
{
dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
if (IS_ERR(dbfs_dir))
return PTR_ERR(dbfs_dir);
return 0;
}
void hypfs_dbfs_exit(void)
{
debugfs_remove(dbfs_dir);
}
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