300 lines
6.4 KiB
C
300 lines
6.4 KiB
C
/**
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* @file oprofilefs.c
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*
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* @remark Copyright 2002 OProfile authors
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* @remark Read the file COPYING
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*
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* @author John Levon
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*
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* A simple filesystem for configuration and
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* access of oprofile.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/oprofile.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <asm/uaccess.h>
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#include "oprof.h"
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#define OPROFILEFS_MAGIC 0x6f70726f
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DEFINE_SPINLOCK(oprofilefs_lock);
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static struct inode * oprofilefs_get_inode(struct super_block * sb, int mode)
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{
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struct inode * inode = new_inode(sb);
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if (inode) {
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inode->i_mode = mode;
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inode->i_uid = 0;
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inode->i_gid = 0;
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inode->i_blksize = PAGE_CACHE_SIZE;
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inode->i_blocks = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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}
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return inode;
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}
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static struct super_operations s_ops = {
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.statfs = simple_statfs,
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.drop_inode = generic_delete_inode,
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};
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ssize_t oprofilefs_str_to_user(char const * str, char __user * buf, size_t count, loff_t * offset)
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{
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return simple_read_from_buffer(buf, count, offset, str, strlen(str));
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}
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#define TMPBUFSIZE 50
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ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user * buf, size_t count, loff_t * offset)
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{
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char tmpbuf[TMPBUFSIZE];
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size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
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if (maxlen > TMPBUFSIZE)
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maxlen = TMPBUFSIZE;
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return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
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}
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int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, size_t count)
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{
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char tmpbuf[TMPBUFSIZE];
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if (!count)
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return 0;
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if (count > TMPBUFSIZE - 1)
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return -EINVAL;
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memset(tmpbuf, 0x0, TMPBUFSIZE);
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if (copy_from_user(tmpbuf, buf, count))
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return -EFAULT;
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spin_lock(&oprofilefs_lock);
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*val = simple_strtoul(tmpbuf, NULL, 0);
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spin_unlock(&oprofilefs_lock);
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return 0;
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}
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static ssize_t ulong_read_file(struct file * file, char __user * buf, size_t count, loff_t * offset)
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{
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unsigned long * val = file->private_data;
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return oprofilefs_ulong_to_user(*val, buf, count, offset);
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}
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static ssize_t ulong_write_file(struct file * file, char const __user * buf, size_t count, loff_t * offset)
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{
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unsigned long * value = file->private_data;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(value, buf, count);
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if (retval)
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return retval;
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return count;
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}
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static int default_open(struct inode * inode, struct file * filp)
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{
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if (inode->u.generic_ip)
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filp->private_data = inode->u.generic_ip;
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return 0;
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}
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static struct file_operations ulong_fops = {
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.read = ulong_read_file,
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.write = ulong_write_file,
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.open = default_open,
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};
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static struct file_operations ulong_ro_fops = {
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.read = ulong_read_file,
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.open = default_open,
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};
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static struct dentry * __oprofilefs_create_file(struct super_block * sb,
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struct dentry * root, char const * name, const struct file_operations * fops,
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int perm)
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{
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struct dentry * dentry;
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struct inode * inode;
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dentry = d_alloc_name(root, name);
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if (!dentry)
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return NULL;
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inode = oprofilefs_get_inode(sb, S_IFREG | perm);
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if (!inode) {
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dput(dentry);
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return NULL;
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}
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inode->i_fop = fops;
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d_add(dentry, inode);
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return dentry;
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}
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int oprofilefs_create_ulong(struct super_block * sb, struct dentry * root,
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char const * name, unsigned long * val)
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{
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struct dentry * d = __oprofilefs_create_file(sb, root, name,
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&ulong_fops, 0644);
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if (!d)
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return -EFAULT;
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d->d_inode->u.generic_ip = val;
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return 0;
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}
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int oprofilefs_create_ro_ulong(struct super_block * sb, struct dentry * root,
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char const * name, unsigned long * val)
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{
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struct dentry * d = __oprofilefs_create_file(sb, root, name,
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&ulong_ro_fops, 0444);
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if (!d)
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return -EFAULT;
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d->d_inode->u.generic_ip = val;
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return 0;
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}
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static ssize_t atomic_read_file(struct file * file, char __user * buf, size_t count, loff_t * offset)
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{
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atomic_t * val = file->private_data;
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return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset);
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}
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static struct file_operations atomic_ro_fops = {
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.read = atomic_read_file,
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.open = default_open,
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};
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int oprofilefs_create_ro_atomic(struct super_block * sb, struct dentry * root,
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char const * name, atomic_t * val)
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{
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struct dentry * d = __oprofilefs_create_file(sb, root, name,
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&atomic_ro_fops, 0444);
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if (!d)
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return -EFAULT;
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d->d_inode->u.generic_ip = val;
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return 0;
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}
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int oprofilefs_create_file(struct super_block * sb, struct dentry * root,
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char const * name, const struct file_operations * fops)
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{
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if (!__oprofilefs_create_file(sb, root, name, fops, 0644))
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return -EFAULT;
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return 0;
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}
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int oprofilefs_create_file_perm(struct super_block * sb, struct dentry * root,
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char const * name, const struct file_operations * fops, int perm)
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{
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if (!__oprofilefs_create_file(sb, root, name, fops, perm))
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return -EFAULT;
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return 0;
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}
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struct dentry * oprofilefs_mkdir(struct super_block * sb,
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struct dentry * root, char const * name)
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{
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struct dentry * dentry;
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struct inode * inode;
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dentry = d_alloc_name(root, name);
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if (!dentry)
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return NULL;
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inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
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if (!inode) {
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dput(dentry);
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return NULL;
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}
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inode->i_op = &simple_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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d_add(dentry, inode);
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return dentry;
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}
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static int oprofilefs_fill_super(struct super_block * sb, void * data, int silent)
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{
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struct inode * root_inode;
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struct dentry * root_dentry;
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sb->s_blocksize = PAGE_CACHE_SIZE;
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sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
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sb->s_magic = OPROFILEFS_MAGIC;
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sb->s_op = &s_ops;
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sb->s_time_gran = 1;
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root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
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if (!root_inode)
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return -ENOMEM;
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root_inode->i_op = &simple_dir_inode_operations;
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root_inode->i_fop = &simple_dir_operations;
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root_dentry = d_alloc_root(root_inode);
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if (!root_dentry) {
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iput(root_inode);
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return -ENOMEM;
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}
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sb->s_root = root_dentry;
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oprofile_create_files(sb, root_dentry);
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// FIXME: verify kill_litter_super removes our dentries
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return 0;
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}
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static int oprofilefs_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data, struct vfsmount *mnt)
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{
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return get_sb_single(fs_type, flags, data, oprofilefs_fill_super, mnt);
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}
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static struct file_system_type oprofilefs_type = {
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.owner = THIS_MODULE,
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.name = "oprofilefs",
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.get_sb = oprofilefs_get_sb,
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.kill_sb = kill_litter_super,
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};
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int __init oprofilefs_register(void)
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{
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return register_filesystem(&oprofilefs_type);
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}
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void __exit oprofilefs_unregister(void)
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{
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unregister_filesystem(&oprofilefs_type);
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}
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