C++ (Cpp) map_vopen Examples

Example #1

File: mapdrv_kmalloc.c Project: edsionte/edsionte-code

int mapdrv_mmap(struct file *file, struct vm_area_struct *vma)
{
	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;

	unsigned long size = vma->vm_end - vma->vm_start;
	if (offset & ~PAGE_MASK) {
		printk("offset not aligned: %ld\n", offset);
		return -ENXIO;
	}
	if (size > MAPLEN) {
		printk("size too big\n");
		return -ENXIO;
	}
	/*  only support shared mappings. */
	if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) {
		printk("writeable mappings must be shared, rejecting\n");
		return -EINVAL;
	}
	/* do not want to have this area swapped out, lock it */
	vma->vm_flags |= VM_LOCKED;
	if (offset == 0) {
		vma->vm_ops = &map_vm_ops;
		//必须主动打开vma
		map_vopen(vma);
	} else {
		printk("offset out of range\n");
		return -ENXIO;
	}
	return 0;
}

Example #2

File: vmalloc_mmap_fault.c Project: exuuwen/study

static int mapdrv_mmap(struct file *file, struct vm_area_struct *vma)
{
	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
	unsigned long size = vma->vm_end - vma->vm_start;
	
	if (offset + size > MAPLEN) 
	{
		printk("size too big\n");
		return -ENXIO;
	}

	/*  only support shared mappings. */
	if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) 
	{
		printk("writeable mappings must be shared, rejecting\n");
		return -EINVAL;
	}
	/* do not want to have this area swapped out, lock it */
	vma->vm_flags |= VM_LOCKED;
	vma->vm_ops = &map_vm_ops;
	/* call the open routine to increment the usage count */
	map_vopen(vma);

	return 0;
}