[dpdk-stable] patch 'vfio: fix duplicated user mem map' has been queued to stable release 20.11.2

[Xueming Li]

Hi,

FYI, your patch has been queued to stable release 20.11.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/12/21. 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. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/steevenlee/dpdk

This queued commit can be viewed at:
https://github.com/steevenlee/dpdk/commit/6b76e06108341de9413374698ae4505a984fb470

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From 6b76e06108341de9413374698ae4505a984fb470 Mon Sep 17 00:00:00 2001
From: Yunjian Wang <wangyunjian at huawei.com>
Date: Sat, 10 Apr 2021 17:37:57 +0800
Subject: [PATCH] vfio: fix duplicated user mem map
Cc: Luca Boccassi <bluca at debian.org>

[ upstream commit 22677b0eef49ec30ef0facadee44b0084fc091ac ]

Currently, new user mem maps are checked if they are adjacent to
an existing mem map and if so, the mem map entries are merged.

It didn't check for duplicate mem maps, so if the API is called
with the same mem map multiple times, they will occupy multiple
mem map entries. This will reduce the amount of entries available
for unique mem maps.

So check for duplicate mem maps and merge them into one mem map
entry if any found.

Fixes: 0cbce3a167f1 ("vfio: skip DMA map failure if already mapped")

Suggested-by: Kevin Traynor <ktraynor at redhat.com>
Signed-off-by: Yunjian Wang <wangyunjian at huawei.com>
Acked-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 lib/librte_eal/linux/eal_vfio.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/librte_eal/linux/eal_vfio.c b/lib/librte_eal/linux/eal_vfio.c
index b15b75882b..c80777bc21 100644
--- a/lib/librte_eal/linux/eal_vfio.c
+++ b/lib/librte_eal/linux/eal_vfio.c
@@ -171,6 +171,10 @@ adjust_map(struct user_mem_map *src, struct user_mem_map *end,
 static int
 merge_map(struct user_mem_map *left, struct user_mem_map *right)
 {
+	/* merge the same maps into one */
+	if (memcmp(left, right, sizeof(struct user_mem_map)) == 0)
+		goto out;
+
 	if (left->addr + left->len != right->addr)
 		return 0;
 	if (left->iova + left->len != right->iova)
@@ -178,6 +182,7 @@ merge_map(struct user_mem_map *left, struct user_mem_map *right)
 
 	left->len += right->len;
 
+out:
 	memset(right, 0, sizeof(*right));
 
 	return 1;
-- 
2.25.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2021-05-10 23:59:31.756170100 +0800
+++ 0201-vfio-fix-duplicated-user-mem-map.patch	2021-05-10 23:59:26.660000000 +0800
@@ -1 +1 @@
-From 22677b0eef49ec30ef0facadee44b0084fc091ac Mon Sep 17 00:00:00 2001
+From 6b76e06108341de9413374698ae4505a984fb470 Mon Sep 17 00:00:00 2001
@@ -4,0 +5,3 @@
+Cc: Luca Boccassi <bluca at debian.org>
+
+[ upstream commit 22677b0eef49ec30ef0facadee44b0084fc091ac ]
@@ -18 +20,0 @@
-Cc: stable at dpdk.org
@@ -28 +30 @@
-index fe25719991..25add2fa5d 100644
+index b15b75882b..c80777bc21 100644