[dpdk-stable] patch 'kni: fix build on Linux < 3.14' has been queued to stable release 18.08.1

[Kevin Traynor]

Hi,

FYI, your patch has been queued to stable release 18.08.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/28/18. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the patch applied
to the branch. If the code is different (ie: not only metadata diffs), due for example to
a change in context or macro names, please double check it.

Thanks.

Kevin Traynor

---
>From 798a282799a1c6fc2bbdb8b5e9d2d46e5b1f5db3 Mon Sep 17 00:00:00 2001
From: Thomas Monjalon <thomas at monjalon.net>
Date: Fri, 26 Oct 2018 23:23:36 +0200
Subject: [PATCH] kni: fix build on Linux < 3.14
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

[ upstream commit c6c36fe28a7bfd8ca21784b2b8b62241f89de06e ]

The atomic functions smp_load_acquire() and smp_store_release()
were introduced in Linux 3.14. Older kernels miss the functions:

kni_fifo.h:19:2: error:
	implicit declaration of function ‘smp_load_acquire’
kni_fifo.h:30:2: error:
	implicit declaration of function ‘smp_store_release’

The fallback is to drop the atomic barrier, as it was before
the commit below.

Fixes: 711859cd0d07 ("kni: fix kernel FIFO synchronization")

Signed-off-by: Thomas Monjalon <thomas at monjalon.net>
---
 kernel/linux/kni/kni_fifo.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/kernel/linux/kni/kni_fifo.h b/kernel/linux/kni/kni_fifo.h
index 2cb3a4a7b..3f4781c2e 100644
--- a/kernel/linux/kni/kni_fifo.h
+++ b/kernel/linux/kni/kni_fifo.h
@@ -9,4 +9,12 @@
 #include <exec-env/rte_kni_common.h>
 
+/* Skip some memory barriers on Linux < 3.14 */
+#ifndef smp_load_acquire
+#define smp_load_acquire(a) (*(a))
+#endif
+#ifndef smp_store_release
+#define smp_store_release(a, b) *(a) = (b)
+#endif
+
 /**
  * Adds num elements into the fifo. Return the number actually written
-- 
2.19.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2018-11-22 16:47:33.326145237 +0000
+++ 0041-kni-fix-build-on-Linux-3.14.patch	2018-11-22 16:47:32.000000000 +0000
@@ -1,4 +1,4 @@
-From c6c36fe28a7bfd8ca21784b2b8b62241f89de06e Mon Sep 17 00:00:00 2001
+From 798a282799a1c6fc2bbdb8b5e9d2d46e5b1f5db3 Mon Sep 17 00:00:00 2001
 From: Thomas Monjalon <thomas at monjalon.net>
 Date: Fri, 26 Oct 2018 23:23:36 +0200
 Subject: [PATCH] kni: fix build on Linux < 3.14
@@ -6,6 +6,8 @@
 Content-Type: text/plain; charset=UTF-8
 Content-Transfer-Encoding: 8bit
 
+[ upstream commit c6c36fe28a7bfd8ca21784b2b8b62241f89de06e ]
+
 The atomic functions smp_load_acquire() and smp_store_release()
 were introduced in Linux 3.14. Older kernels miss the functions: