/*
* acpi_lpat.h - LPAT table processing functions
*
* Copyright (C) 2015 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef ACPI_LPAT_H
#define ACPI_LPAT_H
struct acpi_lpat {
int temp;
int raw;
};
struct acpi_lpat_conversion_table {
struct acpi_lpat *lpat;
int lpat_count;
};
#ifdef CONFIG_ACPI
int acpi_lpat_raw_to_temp(struct acpi_lpat_conversion_table *lpat_table,
int raw);
int acpi_lpat_temp_to_raw(struct acpi_lpat_conversion_table *lpat_table,
int temp);
struct acpi_lpat_conversion_table *acpi_lpat_get_conversion_table(acpi_handle
handle);
void acpi_lpat_free_conversion_table(struct acpi_lpat_conversion_table
*lpat_table);
#else
static int acpi_lpat_raw_to_temp(struct acpi_lpat_conversion_table *lpat_table,
int raw)
{
return 0;
}
static int acpi_lpat_temp_to_raw(struct acpi_lpat_conversion_table *lpat_table,
int temp)
{
return 0;
}
static struct acpi_lpat_conversion_table *acpi_lpat_get_conversion_table(
acpi_handle handle)
{
return NULL;
}
static void acpi_lpat_free_conversion_table(struct acpi_lpat_conversion_table
*lpat_table)
{
}
#endif
#endif
>
summaryrefslogtreecommitdiff
romfs: use different way to generate fsid for BLOCK or MTD
Commit 8a59f5d25265 ("fs/romfs: return f_fsid for statfs(2)") generates
a 64bit id from sb->s_bdev->bd_dev. This is only correct when romfs is
defined with CONFIG_ROMFS_ON_BLOCK. If romfs is only defined with
CONFIG_ROMFS_ON_MTD, sb->s_bdev is NULL, referencing sb->s_bdev->bd_dev
will triger an oops.
Richard Weinberger points out that when CONFIG_ROMFS_BACKED_BY_BOTH=y,
both CONFIG_ROMFS_ON_BLOCK and CONFIG_ROMFS_ON_MTD are defined.
Therefore when calling huge_encode_dev() to generate a 64bit id, I use
the follow order to choose parameter,
- CONFIG_ROMFS_ON_BLOCK defined
use sb->s_bdev->bd_dev
- CONFIG_ROMFS_ON_BLOCK undefined and CONFIG_ROMFS_ON_MTD defined
use sb->s_dev when,
- both CONFIG_ROMFS_ON_BLOCK and CONFIG_ROMFS_ON_MTD undefined
leave id as 0
When CONFIG_ROMFS_ON_MTD is defined and sb->s_mtd is not NULL, sb->s_dev
is set to a device ID generated by MTD_BLOCK_MAJOR and mtd index,
otherwise sb->s_dev is 0.
This is a try-best effort to generate a uniq file system ID, if all the
above conditions are not meet, f_fsid of this romfs instance will be 0.
Generally only one romfs can be built on single MTD block device, this
method is enough to identify multiple romfs instances in a computer.
Link: http://lkml.kernel.org/r/1482928596-115155-1-git-send-email-colyli@suse.de
Signed-off-by: Coly Li <colyli@suse.de>
Reported-by: Nong Li <nongli1031@gmail.com>
Tested-by: Nong Li <nongli1031@gmail.com>
Cc: Richard Weinberger <richard.weinberger@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>