int binder_alloc_mmap_handler()

in binder_alloc.c [750:809]

• 53 lines of code
• 4 McCabe index (conditional complexity)

int binder_alloc_mmap_handler(struct binder_alloc *alloc,
			      struct vm_area_struct *vma)
{
	int ret;
	const char *failure_string;
	struct binder_buffer *buffer;

	mutex_lock(&binder_alloc_mmap_lock);
	if (alloc->buffer_size) {
		ret = -EBUSY;
		failure_string = "already mapped";
		goto err_already_mapped;
	}
	alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
				   SZ_4M);
	mutex_unlock(&binder_alloc_mmap_lock);

	alloc->buffer = (void __user *)vma->vm_start;

	alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
			       sizeof(alloc->pages[0]),
			       GFP_KERNEL);
	if (alloc->pages == NULL) {
		ret = -ENOMEM;
		failure_string = "alloc page array";
		goto err_alloc_pages_failed;
	}

	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
	if (!buffer) {
		ret = -ENOMEM;
		failure_string = "alloc buffer struct";
		goto err_alloc_buf_struct_failed;
	}

	buffer->user_data = alloc->buffer;
	list_add(&buffer->entry, &alloc->buffers);
	buffer->free = 1;
	binder_insert_free_buffer(alloc, buffer);
	alloc->free_async_space = alloc->buffer_size / 2;
	binder_alloc_set_vma(alloc, vma);
	mmgrab(alloc->vma_vm_mm);

	return 0;

err_alloc_buf_struct_failed:
	kfree(alloc->pages);
	alloc->pages = NULL;
err_alloc_pages_failed:
	alloc->buffer = NULL;
	mutex_lock(&binder_alloc_mmap_lock);
	alloc->buffer_size = 0;
err_already_mapped:
	mutex_unlock(&binder_alloc_mmap_lock);
	binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
			   "%s: %d %lx-%lx %s failed %d\n", __func__,
			   alloc->pid, vma->vm_start, vma->vm_end,
			   failure_string, ret);
	return ret;
}