+
+/**
+ * ipath_make_grh - construct a GRH header
+ * @dev: a pointer to the ipath device
+ * @hdr: a pointer to the GRH header being constructed
+ * @grh: the global route address to send to
+ * @hwords: the number of 32 bit words of header being sent
+ * @nwords: the number of 32 bit words of data being sent
+ *
+ * Return the size of the header in 32 bit words.
+ */
+u32 ipath_make_grh(struct ipath_ibdev *dev, struct ib_grh *hdr,
+ struct ib_global_route *grh, u32 hwords, u32 nwords)
+{
+ hdr->version_tclass_flow =
+ cpu_to_be32((6 << 28) |
+ (grh->traffic_class << 20) |
+ grh->flow_label);
+ hdr->paylen = cpu_to_be16((hwords - 2 + nwords + SIZE_OF_CRC) << 2);
+ /* next_hdr is defined by C8-7 in ch. 8.4.1 */
+ hdr->next_hdr = 0x1B;
+ hdr->hop_limit = grh->hop_limit;
+ /* The SGID is 32-bit aligned. */
+ hdr->sgid.global.subnet_prefix = dev->gid_prefix;
+ hdr->sgid.global.interface_id = dev->dd->ipath_guid;
+ hdr->dgid = grh->dgid;
+
+ /* GRH header size in 32-bit words. */
+ return sizeof(struct ib_grh) / sizeof(u32);
+}
+
+/**
+ * ipath_do_ruc_send - perform a send on an RC or UC QP
+ * @data: contains a pointer to the QP
+ *
+ * Process entries in the send work queue until credit or queue is
+ * exhausted. Only allow one CPU to send a packet per QP (tasklet).
+ * Otherwise, after we drop the QP s_lock, two threads could send
+ * packets out of order.
+ */
+void ipath_do_ruc_send(unsigned long data)
+{
+ struct ipath_qp *qp = (struct ipath_qp *)data;
+ struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+ unsigned long flags;
+ u16 lrh0;
+ u32 nwords;
+ u32 extra_bytes;
+ u32 bth0;
+ u32 bth2;
+ u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+ struct ipath_other_headers *ohdr;
+
+ if (test_and_set_bit(IPATH_S_BUSY, &qp->s_flags))
+ goto bail;
+
+ if (unlikely(qp->remote_ah_attr.dlid == dev->dd->ipath_lid)) {
+ ipath_ruc_loopback(qp);
+ goto clear;
+ }
+
+ ohdr = &qp->s_hdr.u.oth;
+ if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
+ ohdr = &qp->s_hdr.u.l.oth;
+
+again:
+ /* Check for a constructed packet to be sent. */
+ if (qp->s_hdrwords != 0) {
+ /*
+ * If no PIO bufs are available, return. An interrupt will
+ * call ipath_ib_piobufavail() when one is available.
+ */
+ if (ipath_verbs_send(dev->dd, qp->s_hdrwords,
+ (u32 *) &qp->s_hdr, qp->s_cur_size,
+ qp->s_cur_sge)) {
+ ipath_no_bufs_available(qp, dev);
+ goto bail;
+ }
+ dev->n_unicast_xmit++;
+ /* Record that we sent the packet and s_hdr is empty. */
+ qp->s_hdrwords = 0;
+ }
+
+ /*
+ * The lock is needed to synchronize between setting
+ * qp->s_ack_state, resend timer, and post_send().
+ */
+ spin_lock_irqsave(&qp->s_lock, flags);
+
+ /* Sending responses has higher priority over sending requests. */
+ if (qp->s_ack_state != IB_OPCODE_RC_ACKNOWLEDGE &&
+ (bth0 = ipath_make_rc_ack(qp, ohdr, pmtu)) != 0)
+ bth2 = qp->s_ack_psn++ & IPATH_PSN_MASK;
+ else if (!((qp->ibqp.qp_type == IB_QPT_RC) ?
+ ipath_make_rc_req(qp, ohdr, pmtu, &bth0, &bth2) :
+ ipath_make_uc_req(qp, ohdr, pmtu, &bth0, &bth2))) {
+ /*
+ * Clear the busy bit before unlocking to avoid races with
+ * adding new work queue items and then failing to process
+ * them.
+ */
+ clear_bit(IPATH_S_BUSY, &qp->s_flags);
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+ goto bail;
+ }
+
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+
+ /* Construct the header. */
+ extra_bytes = (4 - qp->s_cur_size) & 3;
+ nwords = (qp->s_cur_size + extra_bytes) >> 2;
+ lrh0 = IPATH_LRH_BTH;
+ if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
+ qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
+ &qp->remote_ah_attr.grh,
+ qp->s_hdrwords, nwords);
+ lrh0 = IPATH_LRH_GRH;
+ }
+ lrh0 |= qp->remote_ah_attr.sl << 4;
+ qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
+ qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
+ qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
+ SIZE_OF_CRC);
+ qp->s_hdr.lrh[3] = cpu_to_be16(dev->dd->ipath_lid);
+ bth0 |= ipath_get_pkey(dev->dd, qp->s_pkey_index);
+ bth0 |= extra_bytes << 20;
+ ohdr->bth[0] = cpu_to_be32(bth0);
+ ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
+ ohdr->bth[2] = cpu_to_be32(bth2);
+
+ /* Check for more work to do. */
+ goto again;
+
+clear:
+ clear_bit(IPATH_S_BUSY, &qp->s_flags);
+bail:
+ return;
+}