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8e18e2941c
The following patches reduce the size of the VFS inode structure by 28 bytes on a UP x86. (It would be more on an x86_64 system). This is a 10% reduction in the inode size on a UP kernel that is configured in a production mode (i.e., with no spinlock or other debugging functions enabled; if you want to save memory taken up by in-core inodes, the first thing you should do is disable the debugging options; they are responsible for a huge amount of bloat in the VFS inode structure). This patch: The filesystem or device-specific pointer in the inode is inside a union, which is pretty pointless given that all 30+ users of this field have been using the void pointer. Get rid of the union and rename it to i_private, with a comment to explain who is allowed to use the void pointer. This is just a cleanup, but it allows us to reuse the union 'u' for something something where the union will actually be used. [judith@osdl.org: powerpc build fix] Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Judith Lebzelter <judith@osdl.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
292 lines
10 KiB
C
292 lines
10 KiB
C
/*
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* file.c - part of debugfs, a tiny little debug file system
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*
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* Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
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* Copyright (C) 2004 IBM Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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* debugfs is for people to use instead of /proc or /sys.
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* See Documentation/DocBook/kernel-api for more details.
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*
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/debugfs.h>
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static ssize_t default_read_file(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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return 0;
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}
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static ssize_t default_write_file(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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return count;
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}
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static int default_open(struct inode *inode, struct file *file)
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{
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if (inode->i_private)
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file->private_data = inode->i_private;
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return 0;
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}
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const struct file_operations debugfs_file_operations = {
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.read = default_read_file,
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.write = default_write_file,
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.open = default_open,
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};
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static void debugfs_u8_set(void *data, u64 val)
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{
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*(u8 *)data = val;
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}
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static u64 debugfs_u8_get(void *data)
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{
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return *(u8 *)data;
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}
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DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
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/**
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* debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
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* @name: a pointer to a string containing the name of the file to create.
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* @mode: the permission that the file should have
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* @parent: a pointer to the parent dentry for this file. This should be a
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* directory dentry if set. If this parameter is %NULL, then the
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* file will be created in the root of the debugfs filesystem.
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* @value: a pointer to the variable that the file should read to and write
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* from.
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*
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* This function creates a file in debugfs with the given name that
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* contains the value of the variable @value. If the @mode variable is so
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* set, it can be read from, and written to.
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*
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* This function will return a pointer to a dentry if it succeeds. This
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* pointer must be passed to the debugfs_remove() function when the file is
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* to be removed (no automatic cleanup happens if your module is unloaded,
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* you are responsible here.) If an error occurs, %NULL will be returned.
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*
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* If debugfs is not enabled in the kernel, the value -%ENODEV will be
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* returned. It is not wise to check for this value, but rather, check for
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* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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* code.
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*/
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struct dentry *debugfs_create_u8(const char *name, mode_t mode,
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struct dentry *parent, u8 *value)
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{
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return debugfs_create_file(name, mode, parent, value, &fops_u8);
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}
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EXPORT_SYMBOL_GPL(debugfs_create_u8);
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static void debugfs_u16_set(void *data, u64 val)
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{
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*(u16 *)data = val;
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}
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static u64 debugfs_u16_get(void *data)
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{
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return *(u16 *)data;
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}
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DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
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/**
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* debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
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* @name: a pointer to a string containing the name of the file to create.
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* @mode: the permission that the file should have
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* @parent: a pointer to the parent dentry for this file. This should be a
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* directory dentry if set. If this parameter is %NULL, then the
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* file will be created in the root of the debugfs filesystem.
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* @value: a pointer to the variable that the file should read to and write
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* from.
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*
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* This function creates a file in debugfs with the given name that
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* contains the value of the variable @value. If the @mode variable is so
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* set, it can be read from, and written to.
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*
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* This function will return a pointer to a dentry if it succeeds. This
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* pointer must be passed to the debugfs_remove() function when the file is
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* to be removed (no automatic cleanup happens if your module is unloaded,
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* you are responsible here.) If an error occurs, %NULL will be returned.
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*
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* If debugfs is not enabled in the kernel, the value -%ENODEV will be
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* returned. It is not wise to check for this value, but rather, check for
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* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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* code.
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*/
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struct dentry *debugfs_create_u16(const char *name, mode_t mode,
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struct dentry *parent, u16 *value)
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{
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return debugfs_create_file(name, mode, parent, value, &fops_u16);
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}
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EXPORT_SYMBOL_GPL(debugfs_create_u16);
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static void debugfs_u32_set(void *data, u64 val)
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{
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*(u32 *)data = val;
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}
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static u64 debugfs_u32_get(void *data)
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{
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return *(u32 *)data;
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}
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DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
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/**
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* debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
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* @name: a pointer to a string containing the name of the file to create.
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* @mode: the permission that the file should have
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* @parent: a pointer to the parent dentry for this file. This should be a
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* directory dentry if set. If this parameter is %NULL, then the
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* file will be created in the root of the debugfs filesystem.
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* @value: a pointer to the variable that the file should read to and write
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* from.
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*
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* This function creates a file in debugfs with the given name that
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* contains the value of the variable @value. If the @mode variable is so
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* set, it can be read from, and written to.
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*
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* This function will return a pointer to a dentry if it succeeds. This
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* pointer must be passed to the debugfs_remove() function when the file is
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* to be removed (no automatic cleanup happens if your module is unloaded,
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* you are responsible here.) If an error occurs, %NULL will be returned.
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*
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* If debugfs is not enabled in the kernel, the value -%ENODEV will be
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* returned. It is not wise to check for this value, but rather, check for
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* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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* code.
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*/
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struct dentry *debugfs_create_u32(const char *name, mode_t mode,
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struct dentry *parent, u32 *value)
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{
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return debugfs_create_file(name, mode, parent, value, &fops_u32);
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}
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EXPORT_SYMBOL_GPL(debugfs_create_u32);
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static ssize_t read_file_bool(struct file *file, char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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char buf[3];
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u32 *val = file->private_data;
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if (*val)
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buf[0] = 'Y';
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else
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buf[0] = 'N';
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buf[1] = '\n';
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buf[2] = 0x00;
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return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
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}
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static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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char buf[32];
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int buf_size;
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u32 *val = file->private_data;
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buf_size = min(count, (sizeof(buf)-1));
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if (copy_from_user(buf, user_buf, buf_size))
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return -EFAULT;
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switch (buf[0]) {
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case 'y':
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case 'Y':
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case '1':
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*val = 1;
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break;
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case 'n':
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case 'N':
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case '0':
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*val = 0;
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break;
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}
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return count;
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}
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static const struct file_operations fops_bool = {
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.read = read_file_bool,
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.write = write_file_bool,
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.open = default_open,
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};
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/**
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* debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
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* @name: a pointer to a string containing the name of the file to create.
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* @mode: the permission that the file should have
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* @parent: a pointer to the parent dentry for this file. This should be a
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* directory dentry if set. If this parameter is %NULL, then the
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* file will be created in the root of the debugfs filesystem.
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* @value: a pointer to the variable that the file should read to and write
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* from.
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*
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* This function creates a file in debugfs with the given name that
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* contains the value of the variable @value. If the @mode variable is so
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* set, it can be read from, and written to.
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*
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* This function will return a pointer to a dentry if it succeeds. This
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* pointer must be passed to the debugfs_remove() function when the file is
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* to be removed (no automatic cleanup happens if your module is unloaded,
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* you are responsible here.) If an error occurs, %NULL will be returned.
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*
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* If debugfs is not enabled in the kernel, the value -%ENODEV will be
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* returned. It is not wise to check for this value, but rather, check for
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* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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* code.
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*/
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struct dentry *debugfs_create_bool(const char *name, mode_t mode,
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struct dentry *parent, u32 *value)
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{
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return debugfs_create_file(name, mode, parent, value, &fops_bool);
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}
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EXPORT_SYMBOL_GPL(debugfs_create_bool);
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static ssize_t read_file_blob(struct file *file, char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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struct debugfs_blob_wrapper *blob = file->private_data;
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return simple_read_from_buffer(user_buf, count, ppos, blob->data,
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blob->size);
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}
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static struct file_operations fops_blob = {
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.read = read_file_blob,
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.open = default_open,
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};
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/**
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* debugfs_create_blob - create a debugfs file that is used to read and write a binary blob
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* @name: a pointer to a string containing the name of the file to create.
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* @mode: the permission that the file should have
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* @parent: a pointer to the parent dentry for this file. This should be a
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* directory dentry if set. If this parameter is %NULL, then the
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* file will be created in the root of the debugfs filesystem.
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* @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
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* to the blob data and the size of the data.
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*
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* This function creates a file in debugfs with the given name that exports
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* @blob->data as a binary blob. If the @mode variable is so set it can be
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* read from. Writing is not supported.
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*
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* This function will return a pointer to a dentry if it succeeds. This
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* pointer must be passed to the debugfs_remove() function when the file is
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* to be removed (no automatic cleanup happens if your module is unloaded,
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* you are responsible here.) If an error occurs, %NULL will be returned.
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*
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* If debugfs is not enabled in the kernel, the value -%ENODEV will be
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* returned. It is not wise to check for this value, but rather, check for
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* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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* code.
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*/
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struct dentry *debugfs_create_blob(const char *name, mode_t mode,
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struct dentry *parent,
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struct debugfs_blob_wrapper *blob)
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{
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return debugfs_create_file(name, mode, parent, blob, &fops_blob);
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}
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EXPORT_SYMBOL_GPL(debugfs_create_blob);
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