IB/hfi1: Ensure read of producer s_head is correct

The read of s_head in the hfi1_make_rc_req() and
qib_make_rc_req() lack the necesary barrier instuctions.

Correct other ACCESS_ONCE() warnings in the same file.

Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

2 files changed, 8 insertions, 6 deletions

diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c
index 1dd999e9349c..6446179843e9 100644
--- a/drivers/infiniband/hw/hfi1/rc.c
+++ b/drivers/infiniband/hw/hfi1/rc.c
@@ -414,7 +414,7 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
                         goto bail;
                 /* We are in the error state, flush the work request. */
                 smp_read_barrier_depends(); /* see post_one_send() */
-                if (qp->s_last == ACCESS_ONCE(qp->s_head))
+                if (qp->s_last == READ_ONCE(qp->s_head))
                         goto bail;
                 /* If DMAs are in progress, we can't flush immediately. */
                 if (iowait_sdma_pending(&priv->s_iowait)) {
@@ -457,7 +457,8 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
                 newreq = 0;
                 if (qp->s_cur == qp->s_tail) {
                         /* Check if send work queue is empty. */
-                        if (qp->s_tail == qp->s_head) {
+                        smp_read_barrier_depends(); /* see post_one_send() */
+                        if (qp->s_tail == READ_ONCE(qp->s_head)) {
                                 clear_ahg(qp);
                                 goto bail;
                         }
@@ -1590,7 +1591,7 @@ static void rc_rcv_resp(struct hfi1_ibport *ibp,
 
         /* Ignore invalid responses. */
         smp_read_barrier_depends(); /* see post_one_send */
-        if (cmp_psn(psn, ACCESS_ONCE(qp->s_next_psn)) >= 0)
+        if (cmp_psn(psn, READ_ONCE(qp->s_next_psn)) >= 0)
                 goto ack_done;
 
         /* Ignore duplicate responses. */
diff --git a/drivers/infiniband/hw/qib/qib_rc.c b/drivers/infiniband/hw/qib/qib_rc.c
index 031433cb7206..696bcd0d087c 100644
--- a/drivers/infiniband/hw/qib/qib_rc.c
+++ b/drivers/infiniband/hw/qib/qib_rc.c
@@ -257,7 +257,7 @@ int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags)
                         goto bail;
                 /* We are in the error state, flush the work request. */
                 smp_read_barrier_depends(); /* see post_one_send() */
-                if (qp->s_last == ACCESS_ONCE(qp->s_head))
+                if (qp->s_last == READ_ONCE(qp->s_head))
                         goto bail;
                 /* If DMAs are in progress, we can't flush immediately. */
                 if (atomic_read(&priv->s_dma_busy)) {
@@ -303,7 +303,8 @@ int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags)
                 newreq = 0;
                 if (qp->s_cur == qp->s_tail) {
                         /* Check if send work queue is empty. */
-                        if (qp->s_tail == qp->s_head)
+                        smp_read_barrier_depends(); /* see post_one_send() */
+                        if (qp->s_tail == READ_ONCE(qp->s_head))
                                 goto bail;
                         /*
                          * If a fence is requested, wait for previous
@@ -1390,7 +1391,7 @@ static void qib_rc_rcv_resp(struct qib_ibport *ibp,
 
         /* Ignore invalid responses. */
         smp_read_barrier_depends(); /* see post_one_send */
-        if (qib_cmp24(psn, ACCESS_ONCE(qp->s_next_psn)) >= 0)
+        if (qib_cmp24(psn, READ_ONCE(qp->s_next_psn)) >= 0)
                 goto ack_done;
 
         /* Ignore duplicate responses. */