[PATCH AUTOSEL 5.2 09/23] IB/rdmavt: Add new completion inline

[PATCH AUTOSEL 5.2 09/23] IB/rdmavt: Add new completion inline

[Sasha Levin]

From: Mike Marciniszyn <mike.marciniszyn@intel.com>

There is opencoded send completion logic all over all
the drivers.

We need to convert to this routine to enforce ordering
issues for completions.  This routine fixes an ordering
issue where the read of the SWQE fields necessary for creating
the completion can race with a post send if the post send catches
a send queue at the edge of being full.  Is is possible in that situation
to read SWQE fields that are being written.

This new routine insures that SWQE fields are read prior to advancing
the index that post send uses to determine queue fullness.

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>
---
 include/rdma/rdmavt_qp.h | 72 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/include/rdma/rdmavt_qp.h b/include/rdma/rdmavt_qp.h
index 68e38c20afc04..6014f17669071 100644
--- a/include/rdma/rdmavt_qp.h
+++ b/include/rdma/rdmavt_qp.h
@@ -737,6 +737,78 @@ static inline void rvt_put_qp_swqe(struct rvt_qp *qp, struct rvt_swqe *wqe)
 		atomic_dec(&ibah_to_rvtah(wqe->ud_wr.ah)->refcount);
 }
 
+/**
+ * rvt_qp_sqwe_incr - increment ring index
+ * @qp: the qp
+ * @val: the starting value
+ *
+ * Return: the new value wrapping as appropriate
+ */
+static inline u32
+rvt_qp_swqe_incr(struct rvt_qp *qp, u32 val)
+{
+	if (++val >= qp->s_size)
+		val = 0;
+	return val;
+}
+
+/**
+ * rvt_qp_complete_swqe - insert send completion
+ * @qp - the qp
+ * @wqe - the send wqe
+ * @opcode - wc operation (driver dependent)
+ * @status - completion status
+ *
+ * Update the s_last information, and then 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.
+ *
+ * Return: new last
+ */
+static inline u32
+rvt_qp_complete_swqe(struct rvt_qp *qp,
+		     struct rvt_swqe *wqe,
+		     enum ib_wc_opcode opcode,
+		     enum ib_wc_status status)
+{
+	bool need_completion;
+	u64 wr_id;
+	u32 byte_len, last;
+	int flags = wqe->wr.send_flags;
+
+	rvt_put_qp_swqe(qp, wqe);
+
+	need_completion =
+		!(flags & RVT_SEND_RESERVE_USED) &&
+		(!(qp->s_flags & RVT_S_SIGNAL_REQ_WR) ||
+		(flags & IB_SEND_SIGNALED) ||
+		status != IB_WC_SUCCESS);
+	if (need_completion) {
+		wr_id = wqe->wr.wr_id;
+		byte_len = wqe->length;
+		/* above fields required before writing s_last */
+	}
+	last = rvt_qp_swqe_incr(qp, qp->s_last);
+	/* see rvt_qp_is_avail() */
+	smp_store_release(&qp->s_last, last);
+	if (need_completion) {
+		struct ib_wc w = {
+			.wr_id = wr_id,
+			.status = status,
+			.opcode = opcode,
+			.qp = &qp->ibqp,
+			.byte_len = byte_len,
+		};
+
+		rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.send_cq), &w,
+			     status != IB_WC_SUCCESS);
+	}
+	return last;
+}
+
 extern const int  ib_rvt_state_ops[];
 
 struct rvt_dev_info;
-- 
2.20.1

[PATCH AUTOSEL 5.2 10/23] IB/{rdmavt, qib, hfi1}: Convert to new completion API

[Sasha Levin]

From: Mike Marciniszyn <mike.marciniszyn@intel.com>

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

[PATCH AUTOSEL 5.2 11/23] IB/hfi1: Unreserve a flushed OPFN request

[Sasha Levin]

From: Kaike Wan <kaike.wan@intel.com>

When an OPFN request is flushed, the request is completed without
unreserving itself from the send queue. Subsequently, when a new
request is post sent, the following warning will be triggered:

WARNING: CPU: 4 PID: 8130 at rdmavt/qp.c:1761 rvt_post_send+0x72a/0x880 [rdmavt]
Call Trace:
[<ffffffffbbb61e41>] dump_stack+0x19/0x1b
[<ffffffffbb497688>] __warn+0xd8/0x100
[<ffffffffbb4977cd>] warn_slowpath_null+0x1d/0x20
[<ffffffffc01c941a>] rvt_post_send+0x72a/0x880 [rdmavt]
[<ffffffffbb4dcabe>] ? account_entity_dequeue+0xae/0xd0
[<ffffffffbb61d645>] ? __kmalloc+0x55/0x230
[<ffffffffc04e1a4c>] ib_uverbs_post_send+0x37c/0x5d0 [ib_uverbs]
[<ffffffffc04e5e36>] ? rdma_lookup_put_uobject+0x26/0x60 [ib_uverbs]
[<ffffffffc04dbce6>] ib_uverbs_write+0x286/0x460 [ib_uverbs]
[<ffffffffbb6f9457>] ? security_file_permission+0x27/0xa0
[<ffffffffbb641650>] vfs_write+0xc0/0x1f0
[<ffffffffbb64246f>] SyS_write+0x7f/0xf0
[<ffffffffbbb74ddb>] system_call_fastpath+0x22/0x27

This patch fixes the problem by moving rvt_qp_wqe_unreserve() into
rvt_qp_complete_swqe() to simplify the code and make it less
error-prone.

Fixes: ca95f802ef51 ("IB/hfi1: Unreserve a reserved request when it is completed")
Link: https://lore.kernel.org/r/20190715164528.74174.31364.stgit@awfm-01.aw.intel.com
Cc: <stable@vger.kernel.org>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
---
 drivers/infiniband/hw/hfi1/rc.c | 2 --
 include/rdma/rdmavt_qp.h        | 9 ++++-----
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c
index 235bdbc706acc..5c0d90418e8c4 100644
--- a/drivers/infiniband/hw/hfi1/rc.c
+++ b/drivers/infiniband/hw/hfi1/rc.c
@@ -1835,7 +1835,6 @@ void hfi1_rc_send_complete(struct rvt_qp *qp, struct hfi1_opa_header *opah)
 		    cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
 			break;
 		trdma_clean_swqe(qp, wqe);
-		rvt_qp_wqe_unreserve(qp, wqe);
 		trace_hfi1_qp_send_completion(qp, wqe, qp->s_last);
 		rvt_qp_complete_swqe(qp,
 				     wqe,
@@ -1882,7 +1881,6 @@ struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
 	if (cmp_psn(wqe->lpsn, qp->s_sending_psn) < 0 ||
 	    cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
 		trdma_clean_swqe(qp, wqe);
-		rvt_qp_wqe_unreserve(qp, wqe);
 		trace_hfi1_qp_send_completion(qp, wqe, qp->s_last);
 		rvt_qp_complete_swqe(qp,
 				     wqe,
diff --git a/include/rdma/rdmavt_qp.h b/include/rdma/rdmavt_qp.h
index 84d0f36afc2f7..85544777587db 100644
--- a/include/rdma/rdmavt_qp.h
+++ b/include/rdma/rdmavt_qp.h
@@ -540,7 +540,7 @@ static inline void rvt_qp_wqe_reserve(
 /**
  * rvt_qp_wqe_unreserve - clean reserved operation
  * @qp - the rvt qp
- * @wqe - the send wqe
+ * @flags - send wqe flags
  *
  * This decrements the reserve use count.
  *
@@ -552,11 +552,9 @@ static inline void rvt_qp_wqe_reserve(
  * the compiler does not juggle the order of the s_last
  * ring index and the decrementing of s_reserved_used.
  */
-static inline void rvt_qp_wqe_unreserve(
-	struct rvt_qp *qp,
-	struct rvt_swqe *wqe)
+static inline void rvt_qp_wqe_unreserve(struct rvt_qp *qp, int flags)
 {
-	if (unlikely(wqe->wr.send_flags & RVT_SEND_RESERVE_USED)) {
+	if (unlikely(flags & RVT_SEND_RESERVE_USED)) {
 		atomic_dec(&qp->s_reserved_used);
 		/* insure no compiler re-order up to s_last change */
 		smp_mb__after_atomic();
@@ -743,6 +741,7 @@ rvt_qp_complete_swqe(struct rvt_qp *qp,
 	u32 byte_len, last;
 	int flags = wqe->wr.send_flags;
 
+	rvt_qp_wqe_unreserve(qp, flags);
 	rvt_put_qp_swqe(qp, wqe);
 
 	need_completion =
-- 
2.20.1