static int efa_send_wr_complete()

in efawin/verbs.c [1773:1834]

• 46 lines of code
• 5 McCabe index (conditional complexity)

static int efa_send_wr_complete(struct ibv_qp_ex *ibvqpx)
{
	struct efa_qp *qp = to_efa_qp_ex(ibvqpx);
	struct efa_sq *sq = &qp->sq;
	uint32_t max_txbatch = sq->max_batch_wr;
	uint32_t num_wqe_to_copy;
	uint16_t local_idx = 0;
	uint16_t curbatch = 0;
	uint16_t sq_desc_idx;
	uint16_t pc;

	if (unlikely(qp->wr_session_err)) {
		efa_sq_roll_back(sq);
		goto out;
	}

	/*
	 * Copy local queue to device in chunks, handling wraparound and max
	 * doorbell batch.
	 */
	pc = sq->wq.pc - sq->num_wqe_pending;
	sq_desc_idx = pc & sq->wq.desc_mask;

	/* mmio_wc_start() comes from efa_send_wr_start() */
	while (sq->num_wqe_pending) {
		num_wqe_to_copy = min3(sq->num_wqe_pending,
				       sq->wq.wqe_cnt - sq_desc_idx,
				       max_txbatch - curbatch);
		mmio_memcpy_x64((struct efa_io_tx_wqe *)sq->desc +
							sq_desc_idx,
				(struct efa_io_tx_wqe *)sq->local_queue +
							local_idx,
				num_wqe_to_copy * sizeof(struct efa_io_tx_wqe));

		sq->num_wqe_pending -= num_wqe_to_copy;
		local_idx += num_wqe_to_copy;
		curbatch += num_wqe_to_copy;
		pc += num_wqe_to_copy;
		sq_desc_idx = (sq_desc_idx + num_wqe_to_copy) &
			      sq->wq.desc_mask;

		if (curbatch == max_txbatch) {
			mmio_flush_writes();
			efa_sq_ring_doorbell(sq, pc);
			curbatch = 0;
			mmio_wc_start();
		}
	}

	if (curbatch) {
		mmio_flush_writes();
		efa_sq_ring_doorbell(sq, sq->wq.pc);
	}
out:
	/*
	 * Not using mmio_wc_spinunlock as the doorbell write should be done
	 * inside the lock.
	 */
	pthread_spin_unlock(&sq->wq.wqlock);

	return qp->wr_session_err;
}