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300 lines
6.6 KiB
300 lines
6.6 KiB
/** |
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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/fs_context.h> |
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#include <linux/pagemap.h> |
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#include <linux/uaccess.h> |
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#include "oprof.h" |
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#define OPROFILEFS_MAGIC 0x6f70726f |
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DEFINE_RAW_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_ino = get_next_ino(); |
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inode->i_mode = mode; |
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inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
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} |
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return inode; |
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} |
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static const 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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/* |
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* Note: If oprofilefs_ulong_from_user() returns 0, then *val remains |
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* unchanged and might be uninitialized. This follows write syscall |
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* implementation when count is zero: "If count is zero ... [and if] |
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* no errors are detected, 0 will be returned without causing any |
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* other effect." (man 2 write) |
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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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unsigned long flags; |
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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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raw_spin_lock_irqsave(&oprofilefs_lock, flags); |
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*val = simple_strtoul(tmpbuf, NULL, 0); |
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raw_spin_unlock_irqrestore(&oprofilefs_lock, flags); |
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return count; |
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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; |
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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 <= 0) |
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return retval; |
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retval = oprofile_set_ulong(file->private_data, value); |
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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 const 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 = simple_open, |
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.llseek = default_llseek, |
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}; |
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static const struct file_operations ulong_ro_fops = { |
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.read = ulong_read_file, |
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.open = simple_open, |
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.llseek = default_llseek, |
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}; |
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static int __oprofilefs_create_file(struct dentry *root, char const *name, |
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const struct file_operations *fops, int perm, void *priv) |
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{ |
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struct dentry *dentry; |
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struct inode *inode; |
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if (!root) |
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return -ENOMEM; |
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inode_lock(d_inode(root)); |
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dentry = d_alloc_name(root, name); |
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if (!dentry) { |
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inode_unlock(d_inode(root)); |
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return -ENOMEM; |
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} |
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inode = oprofilefs_get_inode(root->d_sb, S_IFREG | perm); |
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if (!inode) { |
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dput(dentry); |
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inode_unlock(d_inode(root)); |
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return -ENOMEM; |
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} |
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inode->i_fop = fops; |
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inode->i_private = priv; |
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d_add(dentry, inode); |
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inode_unlock(d_inode(root)); |
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return 0; |
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} |
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int oprofilefs_create_ulong(struct dentry *root, |
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char const *name, unsigned long *val) |
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{ |
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return __oprofilefs_create_file(root, name, |
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&ulong_fops, 0644, val); |
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} |
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int oprofilefs_create_ro_ulong(struct dentry *root, |
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char const *name, unsigned long *val) |
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{ |
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return __oprofilefs_create_file(root, name, |
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&ulong_ro_fops, 0444, val); |
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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 const struct file_operations atomic_ro_fops = { |
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.read = atomic_read_file, |
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.open = simple_open, |
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.llseek = default_llseek, |
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}; |
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int oprofilefs_create_ro_atomic(struct dentry *root, |
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char const *name, atomic_t *val) |
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{ |
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return __oprofilefs_create_file(root, name, |
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&atomic_ro_fops, 0444, val); |
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} |
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int oprofilefs_create_file(struct dentry *root, |
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char const *name, const struct file_operations *fops) |
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{ |
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return __oprofilefs_create_file(root, name, fops, 0644, NULL); |
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} |
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int oprofilefs_create_file_perm(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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return __oprofilefs_create_file(root, name, fops, perm, NULL); |
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} |
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struct dentry *oprofilefs_mkdir(struct dentry *parent, 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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inode_lock(d_inode(parent)); |
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dentry = d_alloc_name(parent, name); |
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if (!dentry) { |
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inode_unlock(d_inode(parent)); |
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return NULL; |
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} |
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inode = oprofilefs_get_inode(parent->d_sb, S_IFDIR | 0755); |
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if (!inode) { |
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dput(dentry); |
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inode_unlock(d_inode(parent)); |
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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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inode_unlock(d_inode(parent)); |
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return dentry; |
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} |
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static int oprofilefs_fill_super(struct super_block *sb, struct fs_context *fc) |
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{ |
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struct inode *root_inode; |
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sb->s_blocksize = PAGE_SIZE; |
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sb->s_blocksize_bits = PAGE_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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sb->s_root = d_make_root(root_inode); |
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if (!sb->s_root) |
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return -ENOMEM; |
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oprofile_create_files(sb->s_root); |
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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_tree(struct fs_context *fc) |
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{ |
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return get_tree_single(fc, oprofilefs_fill_super); |
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} |
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static const struct fs_context_operations oprofilefs_context_ops = { |
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.get_tree = oprofilefs_get_tree, |
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}; |
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static int oprofilefs_init_fs_context(struct fs_context *fc) |
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{ |
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fc->ops = &oprofilefs_context_ops; |
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return 0; |
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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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.init_fs_context = oprofilefs_init_fs_context, |
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.kill_sb = kill_litter_super, |
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}; |
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MODULE_ALIAS_FS("oprofilefs"); |
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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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