Patch "IB/mlx5: Fix post send fence logic" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    IB/mlx5: Fix post send fence logic

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ib-mlx5-fix-post-send-fence-logic.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c9b254955b9f8814966f5dabd34c39d0e0a2b437 Mon Sep 17 00:00:00 2001
From: Eli Cohen <eli@mellanox.com>
Date: Wed, 22 Jun 2016 17:27:26 +0300
Subject: IB/mlx5: Fix post send fence logic

From: Eli Cohen <eli@mellanox.com>

commit c9b254955b9f8814966f5dabd34c39d0e0a2b437 upstream.

If the caller specified IB_SEND_FENCE in the send flags of the work
request and no previous work request stated that the successive one
should be fenced, the work request would be executed without a fence.
This could result in RDMA read or atomic operations failure due to a MR
being invalidated. Fix this by adding the mlx5 enumeration for fencing
RDMA/atomic operations and fix the logic to apply this.

Fixes: e126ba97dba9 ('mlx5: Add driver for Mellanox Connect-IB adapters')
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/infiniband/hw/mlx5/qp.c |    7 ++++---
 include/linux/mlx5/qp.h         |    1 +
 2 files changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -2527,10 +2527,11 @@ static u8 get_fence(u8 fence, struct ib_
 			return MLX5_FENCE_MODE_SMALL_AND_FENCE;
 		else
 			return fence;
-
-	} else {
-		return 0;
+	} else if (unlikely(wr->send_flags & IB_SEND_FENCE)) {
+		return MLX5_FENCE_MODE_FENCE;
 	}
+
+	return 0;
 }
 
 static int begin_wqe(struct mlx5_ib_qp *qp, void **seg,
--- a/include/linux/mlx5/qp.h
+++ b/include/linux/mlx5/qp.h
@@ -160,6 +160,7 @@ enum {
 enum {
 	MLX5_FENCE_MODE_NONE			= 0 << 5,
 	MLX5_FENCE_MODE_INITIATOR_SMALL		= 1 << 5,
+	MLX5_FENCE_MODE_FENCE			= 2 << 5,
 	MLX5_FENCE_MODE_STRONG_ORDERING		= 3 << 5,
 	MLX5_FENCE_MODE_SMALL_AND_FENCE		= 4 << 5,
 };


Patches currently in stable-queue which might be from eli@mellanox.com are

queue-4.4/ib-mlx5-fix-post-send-fence-logic.patch