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IB/hfi1: Remove usage of qp->s_cur_sge

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The s_cur_sge field in the qp structure holds a pointer to the
SGE of the currently processed WQE. It assumes the protection
of the RVT_S_BUSY flag to prevent the changing of this field
while the send engine is using it. This scheme works as long
as there is only one instance of the send engine running at a
time.

Scaling of the send engine to multiple cores would break this
assumption as there could be multiple instances of the send engine
running on different CPUs. This opens a window where the QP's
RVT_S_BUSY flag is not set but the send engine is still running.

To prevent accidental changing of the s_cur_sge pointer, the QP's
dependence on it is removed. The SGE pointer is now stored in the
verbs_txreq, which is a per-packet data structure. This ensures
that each individual packet has it's own pointer, which is setup
while the RVT_S_BUSY flag is set.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Mitko Haralanov
2016-12-07 19:33:27 -08:00
committed by Doug Ledford
parent fcb29a6668
commit b777f154a0
4 changed files with 13 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/infiniband/hw/hfi1/rc.c
View File

@@ -276,7 +276,7 @@ static int make_rc_ack(struct hfi1_ibdev *dev, struct rvt_qp *qp,
rvt_get_mr(ps->s_txreq->mr);
qp->s_ack_rdma_sge.sge = e->rdma_sge;
qp->s_ack_rdma_sge.num_sge = 1;
qp->s_cur_sge = &qp->s_ack_rdma_sge;
ps->s_txreq->ss = &qp->s_ack_rdma_sge;
if (len > pmtu) {
len = pmtu;
qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
@@ -290,7 +290,7 @@ static int make_rc_ack(struct hfi1_ibdev *dev, struct rvt_qp *qp,
bth2 = mask_psn(qp->s_ack_rdma_psn++);
} else {
/* COMPARE_SWAP or FETCH_ADD */
qp->s_cur_sge = NULL;
ps->s_txreq->ss = NULL;
len = 0;
qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
ohdr->u.at.aeth = hfi1_compute_aeth(qp);
@@ -306,7 +306,7 @@ static int make_rc_ack(struct hfi1_ibdev *dev, struct rvt_qp *qp,
qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
/* FALLTHROUGH */
case OP(RDMA_READ_RESPONSE_MIDDLE):
qp->s_cur_sge = &qp->s_ack_rdma_sge;
ps->s_txreq->ss = &qp->s_ack_rdma_sge;
ps->s_txreq->mr = qp->s_ack_rdma_sge.sge.mr;
if (ps->s_txreq->mr)
rvt_get_mr(ps->s_txreq->mr);
@@ -335,7 +335,7 @@ normal:
*/
qp->s_ack_state = OP(SEND_ONLY);
qp->s_flags &= ~RVT_S_ACK_PENDING;
qp->s_cur_sge = NULL;
ps->s_txreq->ss = NULL;
if (qp->s_nak_state)
ohdr->u.aeth =
cpu_to_be32((qp->r_msn & HFI1_MSN_MASK) |
@@ -801,7 +801,7 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
qp->s_len -= len;
qp->s_hdrwords = hwords;
ps->s_txreq->sde = priv->s_sde;
qp->s_cur_sge = ss;
ps->s_txreq->ss = ss;
ps->s_txreq->s_cur_size = len;
hfi1_make_ruc_header(
qp,