From: Kaike Wan <kaike.wan@xxxxxxxxx>
This locking mechanism is designed to provent vavious memory corruption
scenarios from occurring when requests are pipelined, especially when
RDMA READ/WRITE requests are interleaved with TID RDMA READ/WRITE
requests:
1. READ-AFTER-READ;
2. READ-AFTER-WRITE;
3. WRITE-AFTER-READ;
When memory corruption is likely, a request will be held back until
previous requests have been completed.
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Signed-off-by: Mitko Haralanov <mitko.haralanov@xxxxxxxxx>
Signed-off-by: Kaike Wan <kaike.wan@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
---
drivers/infiniband/hw/hfi1/rc.c | 16 ++++++++++++++
drivers/infiniband/hw/hfi1/tid_rdma.c | 37 +++++++++++++++++++++++++++++++++
drivers/infiniband/hw/hfi1/tid_rdma.h | 11 ++++++++++
drivers/infiniband/hw/hfi1/verbs.h | 3 +++
4 files changed, 67 insertions(+), 0 deletions(-)
diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c
index a5aacf8..349751c 100644
--- a/drivers/infiniband/hw/hfi1/rc.c
+++ b/drivers/infiniband/hw/hfi1/rc.c
@@ -482,6 +482,15 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
len = wqe->length;
ss = &qp->s_sge;
bth2 = mask_psn(qp->s_psn);
+
+ /*
+ * Interlock between various IB requests and TID RDMA
+ * if necessary.
+ */
+ if ((priv->s_flags & HFI1_S_TID_WAIT_INTERLCK) ||
+ hfi1_tid_rdma_wqe_interlock(qp, wqe))
+ goto bail;
+
switch (wqe->wr.opcode) {
case IB_WR_SEND:
case IB_WR_SEND_WITH_IMM:
@@ -1321,6 +1330,7 @@ static void reset_psn(struct rvt_qp *qp, u32 psn)
qp->s_state = OP(SEND_LAST);
}
done:
+ priv->s_flags &= ~HFI1_S_TID_WAIT_INTERLCK;
qp->s_psn = psn;
/*
* Set RVT_S_WAIT_PSN as rc_complete() may start the timer
@@ -1540,6 +1550,8 @@ struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
struct rvt_swqe *wqe,
struct hfi1_ibport *ibp)
{
+ struct hfi1_qp_priv *priv = qp->priv;
+
lockdep_assert_held(&qp->s_lock);
/*
* Don't decrement refcount and don't generate a
@@ -1608,6 +1620,10 @@ struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
qp->s_draining = 0;
wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
}
+ if (priv->s_flags & HFI1_S_TID_WAIT_INTERLCK) {
+ priv->s_flags &= ~HFI1_S_TID_WAIT_INTERLCK;
+ hfi1_schedule_send(qp);
+ }
return wqe;
}
diff --git a/drivers/infiniband/hw/hfi1/tid_rdma.c b/drivers/infiniband/hw/hfi1/tid_rdma.c
index f4cda45..135667b 100644
--- a/drivers/infiniband/hw/hfi1/tid_rdma.c
+++ b/drivers/infiniband/hw/hfi1/tid_rdma.c
@@ -2825,3 +2825,40 @@ void hfi1_qp_kern_exp_rcv_clear_all(struct rvt_qp *qp)
} while (!ret);
}
}
+
+bool hfi1_tid_rdma_wqe_interlock(struct rvt_qp *qp, struct rvt_swqe *wqe)
+{
+ struct rvt_swqe *prev;
+ struct hfi1_qp_priv *priv = qp->priv;
+ u32 s_prev;
+
+ s_prev = (qp->s_cur == 0 ? qp->s_size : qp->s_cur) - 1;
+ prev = rvt_get_swqe_ptr(qp, s_prev);
+
+ switch (wqe->wr.opcode) {
+ case IB_WR_SEND:
+ case IB_WR_SEND_WITH_IMM:
+ case IB_WR_SEND_WITH_INV:
+ case IB_WR_ATOMIC_CMP_AND_SWP:
+ case IB_WR_ATOMIC_FETCH_AND_ADD:
+ case IB_WR_RDMA_WRITE:
+ case IB_WR_RDMA_READ:
+ break;
+ case IB_WR_TID_RDMA_READ:
+ switch (prev->wr.opcode) {
+ case IB_WR_RDMA_READ:
+ if (qp->s_acked != qp->s_cur)
+ goto interlock;
+ break;
+ default:
+ break;
+ }
+ default:
+ break;
+ }
+ return false;
+
+interlock:
+ priv->s_flags |= HFI1_S_TID_WAIT_INTERLCK;
+ return true;
+}
diff --git a/drivers/infiniband/hw/hfi1/tid_rdma.h b/drivers/infiniband/hw/hfi1/tid_rdma.h
index 4f85b7e..689a549 100644
--- a/drivers/infiniband/hw/hfi1/tid_rdma.h
+++ b/drivers/infiniband/hw/hfi1/tid_rdma.h
@@ -17,6 +17,16 @@
#define TID_RDMA_MAX_SEGMENT_SIZE BIT(18) /* 256 KiB (for now) */
#define TID_RDMA_MAX_PAGES (BIT(18) >> PAGE_SHIFT)
+/*
+ * Bit definitions for priv->s_flags.
+ * These bit flags overload the bit flags defined for the QP's s_flags.
+ * Due to the fact that these bit fields are used only for the QP priv
+ * s_flags, there are no collisions.
+ *
+ * HFI1_S_TID_WAIT_INTERLCK - QP is waiting for requester interlock
+ */
+#define HFI1_S_TID_WAIT_INTERLCK BIT(5)
+
struct tid_rdma_params {
struct rcu_head rcu_head;
u32 qp;
@@ -210,5 +220,6 @@ bool hfi1_handle_kdeth_eflags(struct hfi1_ctxtdata *rcd,
void hfi1_tid_rdma_restart_req(struct rvt_qp *qp, struct rvt_swqe *wqe,
u32 *bth2);
void hfi1_qp_kern_exp_rcv_clear_all(struct rvt_qp *qp);
+bool hfi1_tid_rdma_wqe_interlock(struct rvt_qp *qp, struct rvt_swqe *wqe);
#endif /* HFI1_TID_RDMA_H */
diff --git a/drivers/infiniband/hw/hfi1/verbs.h b/drivers/infiniband/hw/hfi1/verbs.h
index 7642b59..841727a 100644
--- a/drivers/infiniband/hw/hfi1/verbs.h
+++ b/drivers/infiniband/hw/hfi1/verbs.h
@@ -171,6 +171,9 @@ struct hfi1_qp_priv {
u8 hdr_type; /* 9B or 16B */
unsigned long tid_timer_timeout_jiffies;
+ /* variables for the TID RDMA SE state machine */
+ u32 s_flags;
+
/* For TID RDMA READ */
u32 tid_r_reqs; /* Num of tid reads requested */
u32 tid_r_comp; /* Num of tid reads completed */
