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