220 lines
5.6 KiB
C
220 lines
5.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Hypervisor filesystem for Linux on s390. Diag 204 and 224
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* implementation.
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*
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* Copyright IBM Corp. 2006, 2008
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* Author(s): Michael Holzheu <holzheu@de.ibm.com>
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*/
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#define KMSG_COMPONENT "hypfs"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <asm/diag.h>
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#include <asm/ebcdic.h>
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#include "hypfs_diag.h"
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#include "hypfs.h"
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#define DBFS_D204_HDR_VERSION 0
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static enum diag204_sc diag204_store_sc; /* used subcode for store */
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static enum diag204_format diag204_info_type; /* used diag 204 data format */
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static void *diag204_buf; /* 4K aligned buffer for diag204 data */
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static int diag204_buf_pages; /* number of pages for diag204 data */
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static struct dentry *dbfs_d204_file;
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enum diag204_format diag204_get_info_type(void)
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{
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return diag204_info_type;
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}
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static void diag204_set_info_type(enum diag204_format type)
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{
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diag204_info_type = type;
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}
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/* Diagnose 204 functions */
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/*
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* For the old diag subcode 4 with simple data format we have to use real
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* memory. If we use subcode 6 or 7 with extended data format, we can (and
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* should) use vmalloc, since we need a lot of memory in that case. Currently
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* up to 93 pages!
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*/
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static void diag204_free_buffer(void)
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{
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vfree(diag204_buf);
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diag204_buf = NULL;
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}
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void *diag204_get_buffer(enum diag204_format fmt, int *pages)
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{
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if (diag204_buf) {
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*pages = diag204_buf_pages;
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return diag204_buf;
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}
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if (fmt == DIAG204_INFO_SIMPLE) {
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*pages = 1;
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} else {/* DIAG204_INFO_EXT */
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*pages = diag204((unsigned long)DIAG204_SUBC_RSI |
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(unsigned long)DIAG204_INFO_EXT, 0, NULL);
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if (*pages <= 0)
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return ERR_PTR(-EOPNOTSUPP);
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}
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diag204_buf = __vmalloc_node(array_size(*pages, PAGE_SIZE),
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PAGE_SIZE, GFP_KERNEL, NUMA_NO_NODE,
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__builtin_return_address(0));
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if (!diag204_buf)
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return ERR_PTR(-ENOMEM);
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diag204_buf_pages = *pages;
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return diag204_buf;
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}
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/*
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* diag204_probe() has to find out, which type of diagnose 204 implementation
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* we have on our machine. Currently there are three possible scanarios:
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* - subcode 4 + simple data format (only one page)
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* - subcode 4-6 + extended data format
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* - subcode 4-7 + extended data format
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*
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* Subcode 5 is used to retrieve the size of the data, provided by subcodes
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* 6 and 7. Subcode 7 basically has the same function as subcode 6. In addition
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* to subcode 6 it provides also information about secondary cpus.
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* In order to get as much information as possible, we first try
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* subcode 7, then 6 and if both fail, we use subcode 4.
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*/
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static int diag204_probe(void)
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{
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void *buf;
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int pages, rc;
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buf = diag204_get_buffer(DIAG204_INFO_EXT, &pages);
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if (!IS_ERR(buf)) {
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if (diag204((unsigned long)DIAG204_SUBC_STIB7 |
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(unsigned long)DIAG204_INFO_EXT, pages, buf) >= 0) {
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diag204_store_sc = DIAG204_SUBC_STIB7;
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diag204_set_info_type(DIAG204_INFO_EXT);
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goto out;
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}
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if (diag204((unsigned long)DIAG204_SUBC_STIB6 |
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(unsigned long)DIAG204_INFO_EXT, pages, buf) >= 0) {
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diag204_store_sc = DIAG204_SUBC_STIB6;
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diag204_set_info_type(DIAG204_INFO_EXT);
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goto out;
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}
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diag204_free_buffer();
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}
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/* subcodes 6 and 7 failed, now try subcode 4 */
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buf = diag204_get_buffer(DIAG204_INFO_SIMPLE, &pages);
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if (IS_ERR(buf)) {
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rc = PTR_ERR(buf);
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goto fail_alloc;
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}
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if (diag204((unsigned long)DIAG204_SUBC_STIB4 |
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(unsigned long)DIAG204_INFO_SIMPLE, pages, buf) >= 0) {
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diag204_store_sc = DIAG204_SUBC_STIB4;
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diag204_set_info_type(DIAG204_INFO_SIMPLE);
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goto out;
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} else {
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rc = -EOPNOTSUPP;
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goto fail_store;
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}
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out:
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rc = 0;
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fail_store:
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diag204_free_buffer();
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fail_alloc:
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return rc;
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}
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int diag204_store(void *buf, int pages)
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{
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int rc;
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rc = diag204((unsigned long)diag204_store_sc |
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(unsigned long)diag204_get_info_type(), pages, buf);
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return rc < 0 ? -EOPNOTSUPP : 0;
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}
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struct dbfs_d204_hdr {
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u64 len; /* Length of d204 buffer without header */
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u16 version; /* Version of header */
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u8 sc; /* Used subcode */
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char reserved[53];
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} __attribute__ ((packed));
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struct dbfs_d204 {
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struct dbfs_d204_hdr hdr; /* 64 byte header */
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char buf[]; /* d204 buffer */
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} __attribute__ ((packed));
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static int dbfs_d204_create(void **data, void **data_free_ptr, size_t *size)
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{
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struct dbfs_d204 *d204;
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int rc, buf_size;
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void *base;
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buf_size = PAGE_SIZE * (diag204_buf_pages + 1) + sizeof(d204->hdr);
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base = vzalloc(buf_size);
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if (!base)
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return -ENOMEM;
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d204 = PTR_ALIGN(base + sizeof(d204->hdr), PAGE_SIZE) - sizeof(d204->hdr);
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rc = diag204_store(d204->buf, diag204_buf_pages);
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if (rc) {
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vfree(base);
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return rc;
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}
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d204->hdr.version = DBFS_D204_HDR_VERSION;
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d204->hdr.len = PAGE_SIZE * diag204_buf_pages;
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d204->hdr.sc = diag204_store_sc;
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*data = d204;
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*data_free_ptr = base;
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*size = d204->hdr.len + sizeof(struct dbfs_d204_hdr);
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return 0;
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}
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static struct hypfs_dbfs_file dbfs_file_d204 = {
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.name = "diag_204",
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.data_create = dbfs_d204_create,
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.data_free = vfree,
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};
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__init int hypfs_diag_init(void)
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{
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int rc;
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if (diag204_probe()) {
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pr_info("The hardware system does not support hypfs\n");
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return -ENODATA;
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}
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if (diag204_get_info_type() == DIAG204_INFO_EXT)
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hypfs_dbfs_create_file(&dbfs_file_d204);
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rc = hypfs_diag_fs_init();
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if (rc) {
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pr_err("The hardware system does not provide all functions required by hypfs\n");
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debugfs_remove(dbfs_d204_file);
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}
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return rc;
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}
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void hypfs_diag_exit(void)
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{
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debugfs_remove(dbfs_d204_file);
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hypfs_diag_fs_exit();
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diag204_free_buffer();
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hypfs_dbfs_remove_file(&dbfs_file_d204);
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}
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