[PATCH 5.2 22/37] IB/{rdmavt, qib, hfi1}: Convert to new completion API

Greg Kroah-Hartman
2019-09-13T13:22:26Z

Convert all completions to use the new completion routine that
fixes a race between post send and completion where fields from
a SWQE can be read after SWQE has been freed.

This patch also addresses issues reported in
https://marc.info/?l=linux-kernel&m=155656897409107&w=2.

The reserved operation path has no need for any barrier.

The barrier for the other path is addressed by the
smp_load_acquire() barrier.

Cc: Andrea Parri <andrea.parri@amarulasolutions.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@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>
---
drivers/infiniband/hw/hfi1/rc.c | 26 ++++-----------------
drivers/infiniband/hw/qib/qib_rc.c | 26 ++++-----------------
drivers/infiniband/sw/rdmavt/qp.c | 31 ++++++++-----------------
include/rdma/rdmavt_qp.h | 36 ------------------------------
4 files changed, 17 insertions(+), 102 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c
index 7c8cfb149da09..235bdbc706acc 100644
--- a/drivers/infiniband/hw/hfi1/rc.c
+++ b/drivers/infiniband/hw/hfi1/rc.c
@@ -1830,23 +1830,14 @@ void hfi1_rc_send_complete(struct rvt_qp *qp, struct hfi1_opa_header *opah)
}

while (qp->s_last != qp->s_acked) {
- u32 s_last;
-
wqe = rvt_get_swqe_ptr(qp, qp->s_last);
if (cmp_psn(wqe->lpsn, qp->s_sending_psn) >= 0 &&
cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
break;
trdma_clean_swqe(qp, wqe);
rvt_qp_wqe_unreserve(qp, wqe);
- s_last = qp->s_last;
- trace_hfi1_qp_send_completion(qp, wqe, s_last);
- if (++s_last >= qp->s_size)
- s_last = 0;
- qp->s_last = s_last;
- /* see post_send() */
- barrier();
- rvt_put_qp_swqe(qp, wqe);
- rvt_qp_swqe_complete(qp,
+ trace_hfi1_qp_send_completion(qp, wqe, qp->s_last);
+ rvt_qp_complete_swqe(qp,
wqe,
ib_hfi1_wc_opcode[wqe->wr.opcode],
IB_WC_SUCCESS);
@@ -1890,19 +1881,10 @@ struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
trace_hfi1_rc_completion(qp, wqe->lpsn);
if (cmp_psn(wqe->lpsn, qp->s_sending_psn) < 0 ||
cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
- u32 s_last;
-
trdma_clean_swqe(qp, wqe);
- rvt_put_qp_swqe(qp, wqe);
rvt_qp_wqe_unreserve(qp, wqe);
- s_last = qp->s_last;
- trace_hfi1_qp_send_completion(qp, wqe, s_last);
- if (++s_last >= qp->s_size)
- s_last = 0;
- qp->s_last = s_last;
- /* see post_send() */
- barrier();
- rvt_qp_swqe_complete(qp,
+ trace_hfi1_qp_send_completion(qp, wqe, qp->s_last);
+ rvt_qp_complete_swqe(qp,
wqe,
ib_hfi1_wc_opcode[wqe->wr.opcode],
IB_WC_SUCCESS);
diff --git a/drivers/infiniband/hw/qib/qib_rc.c b/drivers/infiniband/hw/qib/qib_rc.c
index 2ac4c67f5ba1a..8d9a94d6f6856 100644
--- a/drivers/infiniband/hw/qib/qib_rc.c
+++ b/drivers/infiniband/hw/qib/qib_rc.c
@@ -921,20 +921,11 @@ void qib_rc_send_complete(struct rvt_qp *qp, struct ib_header *hdr)
rvt_add_retry_timer(qp);

while (qp->s_last != qp->s_acked) {
- u32 s_last;
-
wqe = rvt_get_swqe_ptr(qp, qp->s_last);
if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) >= 0 &&
qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
break;
- s_last = qp->s_last;
- if (++s_last >= qp->s_size)
- s_last = 0;
- qp->s_last = s_last;
- /* see post_send() */
- barrier();
- rvt_put_qp_swqe(qp, wqe);
- rvt_qp_swqe_complete(qp,
+ rvt_qp_complete_swqe(qp,
wqe,
ib_qib_wc_opcode[wqe->wr.opcode],
IB_WC_SUCCESS);
@@ -972,21 +963,12 @@ static struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
* is finished.
*/
if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) < 0 ||
- qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
- u32 s_last;
-
- rvt_put_qp_swqe(qp, wqe);
- s_last = qp->s_last;
- if (++s_last >= qp->s_size)
- s_last = 0;
- qp->s_last = s_last;
- /* see post_send() */
- barrier();
- rvt_qp_swqe_complete(qp,
+ qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0)
+ rvt_qp_complete_swqe(qp,
wqe,
ib_qib_wc_opcode[wqe->wr.opcode],
IB_WC_SUCCESS);
- } else
+ else
this_cpu_inc(*ibp->rvp.rc_delayed_comp);

qp->s_retry = qp->s_retry_cnt;
diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c
index c5a50614a6c63..cb9e171d7e7bf 100644
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/drivers/infiniband/sw/rdmavt/qp.c
@@ -1856,10 +1856,9 @@ static inline int rvt_qp_is_avail(

/* see rvt_qp_wqe_unreserve() */
smp_mb__before_atomic();
- reserved_used = atomic_read(&qp->s_reserved_used);
if (unlikely(reserved_op)) {
/* see rvt_qp_wqe_unreserve() */
- smp_mb__before_atomic();
+ reserved_used = atomic_read(&qp->s_reserved_used);
if (reserved_used >= rdi->dparms.reserved_operations)
return -ENOMEM;
return 0;
@@ -1867,14 +1866,13 @@ static inline int rvt_qp_is_avail(
/* non-reserved operations */
if (likely(qp->s_avail))
return 0;
- slast = READ_ONCE(qp->s_last);
+ /* See rvt_qp_complete_swqe() */
+ slast = smp_load_acquire(&qp->s_last);
if (qp->s_head >= slast)
avail = qp->s_size - (qp->s_head - slast);
else
avail = slast - qp->s_head;

- /* see rvt_qp_wqe_unreserve() */
- smp_mb__before_atomic();
reserved_used = atomic_read(&qp->s_reserved_used);
avail = avail - 1 -
(rdi->dparms.reserved_operations - reserved_used);
@@ -2667,27 +2665,16 @@ void rvt_send_complete(struct rvt_qp *qp, struct rvt_swqe *wqe,
enum ib_wc_status status)
{
u32 old_last, last;
- struct rvt_dev_info *rdi = ib_to_rvt(qp->ibqp.device);
+ struct rvt_dev_info *rdi;

if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_OR_FLUSH_SEND))
return;
+ rdi = ib_to_rvt(qp->ibqp.device);

- last = qp->s_last;
- old_last = last;
- trace_rvt_qp_send_completion(qp, wqe, last);
- if (++last >= qp->s_size)
- last = 0;
- trace_rvt_qp_send_completion(qp, wqe, last);
- qp->s_last = last;
- /* See post_send() */
- barrier();
- rvt_put_qp_swqe(qp, wqe);
-
- rvt_qp_swqe_complete(qp,
- wqe,
- rdi->wc_opcode[wqe->wr.opcode],
- status);
-
+ old_last = qp->s_last;
+ trace_rvt_qp_send_completion(qp, wqe, old_last);
+ last = rvt_qp_complete_swqe(qp, wqe, rdi->wc_opcode[wqe->wr.opcode],
+ status);
if (qp->s_acked == old_last)
qp->s_acked = last;
if (qp->s_cur == old_last)
diff --git a/include/rdma/rdmavt_qp.h b/include/rdma/rdmavt_qp.h
index 6014f17669071..84d0f36afc2f7 100644
--- a/include/rdma/rdmavt_qp.h
+++ b/include/rdma/rdmavt_qp.h
@@ -565,42 +565,6 @@ static inline void rvt_qp_wqe_unreserve(

extern const enum ib_wc_opcode ib_rvt_wc_opcode[];

-/**
- * rvt_qp_swqe_complete() - insert send completion
- * @qp - the qp
- * @wqe - the send wqe
- * @status - completion status
- *
- * Insert a send completion into the completion
- * queue if the qp indicates it should be done.
- *
- * See IBTA 10.7.3.1 for info on completion
- * control.
- */
-static inline void rvt_qp_swqe_complete(
- struct rvt_qp *qp,
- struct rvt_swqe *wqe,
- enum ib_wc_opcode opcode,
- enum ib_wc_status status)
-{
- if (unlikely(wqe->wr.send_flags & RVT_SEND_RESERVE_USED))
- return;
- if (!(qp->s_flags & RVT_S_SIGNAL_REQ_WR) ||
- (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
- status != IB_WC_SUCCESS) {
- struct ib_wc wc;
-
- memset(&wc, 0, sizeof(wc));
- wc.wr_id = wqe->wr.wr_id;
- wc.status = status;
- wc.opcode = opcode;
- wc.qp = &qp->ibqp;
- wc.byte_len = wqe->length;
- rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.send_cq), &wc,
- status != IB_WC_SUCCESS);
- }
-}
-
/*
* Compare the lower 24 bits of the msn values.
* Returns an integer <, ==, or > than zero.
--
2.20.1