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d54b1fdb1d
Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
299 lines
6.4 KiB
C
299 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_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->i_private)
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filp->private_data = inode->i_private;
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return 0;
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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 = default_open,
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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 = 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->i_private = 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->i_private = 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 const 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->i_private = 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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