linux-2.6.32.61/fs/sysfs/bin.c

mmap.c

static int mmap(struct file *file, struct vm_area_struct *vma)
{
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
	int rc;

	mutex_lock(&bb->mutex);

	/* need attr_sd for attr, its parent for kobj */
	rc = -ENODEV;
	if (!sysfs_get_active_two(attr_sd))
		goto out_unlock;

	rc = -EINVAL;
	if (!attr->mmap)
		goto out_put;

	rc = attr->mmap(kobj, attr, vma);
	if (rc)
		goto out_put;

	/*
	 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
	 * to satisfy versions of X which crash if the mmap fails: that
	 * substitutes a new vm_file, and we don't then want bin_vm_ops.
	 */
	if (vma->vm_file != file)
		goto out_put;

	rc = -EINVAL;
	if (bb->mmapped && bb->vm_ops != vma->vm_ops)
		goto out_put;

	rc = 0;
	bb->mmapped = 1;
	bb->vm_ops = vma->vm_ops;
	vma->vm_ops = &bin_vm_ops;
out_put:
	sysfs_put_active_two(attr_sd);
out_unlock:
	mutex_unlock(&bb->mutex);

	return rc;
}