int vmbus_sendpacket_pagebuffer()

in channel.c [1077:1126]

• 39 lines of code
• 3 McCabe index (conditional complexity)

int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
				struct hv_page_buffer pagebuffers[],
				u32 pagecount, void *buffer, u32 bufferlen,
				u64 requestid)
{
	int i;
	struct vmbus_channel_packet_page_buffer desc;
	u32 descsize;
	u32 packetlen;
	u32 packetlen_aligned;
	struct kvec bufferlist[3];
	u64 aligned_data = 0;

	if (pagecount > MAX_PAGE_BUFFER_COUNT)
		return -EINVAL;

	/*
	 * Adjust the size down since vmbus_channel_packet_page_buffer is the
	 * largest size we support
	 */
	descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
			  ((MAX_PAGE_BUFFER_COUNT - pagecount) *
			  sizeof(struct hv_page_buffer));
	packetlen = descsize + bufferlen;
	packetlen_aligned = ALIGN(packetlen, sizeof(u64));

	/* Setup the descriptor */
	desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
	desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
	desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
	desc.length8 = (u16)(packetlen_aligned >> 3);
	desc.transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
	desc.reserved = 0;
	desc.rangecount = pagecount;

	for (i = 0; i < pagecount; i++) {
		desc.range[i].len = pagebuffers[i].len;
		desc.range[i].offset = pagebuffers[i].offset;
		desc.range[i].pfn	 = pagebuffers[i].pfn;
	}

	bufferlist[0].iov_base = &desc;
	bufferlist[0].iov_len = descsize;
	bufferlist[1].iov_base = buffer;
	bufferlist[1].iov_len = bufferlen;
	bufferlist[2].iov_base = &aligned_data;
	bufferlist[2].iov_len = (packetlen_aligned - packetlen);

	return hv_ringbuffer_write(channel, bufferlist, 3, requestid);
}