USB: mon nopage

/*

 * Map ring pages to user space.

 */

struct page *mon_bin_vma_nopage(struct vm_area_struct *vma,

                                unsigned long address, int *type)

static int mon_bin_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)

{

	struct mon_reader_bin *rp = vma->vm_private_data;

	unsigned long offset, chunk_idx;

	struct page *pageptr;

	offset = (address - vma->vm_start) + (vma->vm_pgoff << PAGE_SHIFT);

	offset = vmf->pgoff << PAGE_SHIFT;

	if (offset >= rp->b_size)

		return NOPAGE_SIGBUS;

		return VM_FAULT_SIGBUS;

	chunk_idx = offset / CHUNK_SIZE;

	pageptr = rp->b_vec[chunk_idx].pg;

	get_page(pageptr);

	if (type)

		*type = VM_FAULT_MINOR;

	return pageptr;

	vmf->page = pageptr;

	return 0;

}

struct vm_operations_struct mon_bin_vm_ops = {

	.open =     mon_bin_vma_open,

	.close =    mon_bin_vma_close,

	.nopage =   mon_bin_vma_nopage,

	.fault =    mon_bin_vma_fault,

};

int mon_bin_mmap(struct file *filp, struct vm_area_struct *vma)

{

	/* don't do anything here: "nopage" will set up page table entries */

	/* don't do anything here: "fault" will set up page table entries */

	vma->vm_ops = &mon_bin_vm_ops;

	vma->vm_flags |= VM_RESERVED;

	vma->vm_private_data = filp->private_data;