[dpdk-stable] patch 'vhost: fix multiple queue not enabled for old kernels' has been queued to stable release 17.02.1

[Yuanhan Liu]

Hi,

FYI, your patch has been queued to stable release 17.02.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/28/17. So please
shout if anyone has objections.

Thanks.

	--yliu

---
>From d8338e85c649621fcee96e9d9b7543b5a42bc83d Mon Sep 17 00:00:00 2001
From: Yuanhan Liu <yuanhan.liu at linux.intel.com>
Date: Wed, 1 Mar 2017 18:41:58 +0800
Subject: [PATCH] vhost: fix multiple queue not enabled for old kernels

[ upstream commit 8d286dbeb8d70551ab520569cf8a0ecdec319826 ]

Some macros (say VIRTIO_NET_F_MQ) are needed for enabling multiple queue,
however they are introduced since kernel v3.8, meaning build error happens
if we build DPDK vhost on those platforms.

71dfdbe66a66 ("vhost: fix build with kernel < 3.8") meant to fix it, but
in a wrong way: it completely disables the MQ features for those kernels.
However, the MQ feature doesn't depend on the kernel at all (except the
macros dependency stated above), that we could still enable the MQ feature
even the host kernel has no such support.

The right fix is to define the macro if it's not defined.

Fixes: 71dfdbe66a66 ("vhost: fix build with kernel < 3.8")

Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 lib/librte_vhost/vhost.c | 2 +-
 lib/librte_vhost/vhost.h | 7 +++----
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index e415093..3c3f6a4 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -56,7 +56,7 @@
 				(1ULL << VIRTIO_NET_F_CTRL_VQ) | \
 				(1ULL << VIRTIO_NET_F_CTRL_RX) | \
 				(1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE) | \
-				(VHOST_SUPPORTS_MQ)            | \
+				(1ULL << VIRTIO_NET_F_MQ)      | \
 				(1ULL << VIRTIO_F_VERSION_1)   | \
 				(1ULL << VHOST_F_LOG_ALL)      | \
 				(1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 22564f1..4391e62 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -123,11 +123,10 @@ struct vhost_virtqueue {
  * code buildable for older kernel.
  */
 #ifdef VIRTIO_NET_F_MQ
- #define VHOST_MAX_QUEUE_PAIRS	VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX
- #define VHOST_SUPPORTS_MQ	(1ULL << VIRTIO_NET_F_MQ)
+ #define VHOST_MAX_QUEUE_PAIRS		VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX
 #else
- #define VHOST_MAX_QUEUE_PAIRS	1
- #define VHOST_SUPPORTS_MQ	0
+ #define VIRTIO_NET_F_MQ		22
+ #define VHOST_MAX_QUEUE_PAIRS		0x8000
 #endif
 
 /*
-- 
1.9.0