IB/hfi1: Add interlock between a TID RDMA request and other requests

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@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/tid_rdma.h b/drivers/infiniband/hw/hfi1/tid_rdma.h
index 4f85b7ea5cf3..689a5490432f 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 */