-----Original Message-----
From: wangyunjian
Sent: Monday, December 7, 2020 7:09 PM
To: dev@dpdk.org
Cc: david.marchand@redhat.com; thomas@monjalon.net;
anatoly.burakov@intel.com; Lilijun (Jerry) [off-list ref]; xudingke
[off-list ref]; wangyunjian [off-list ref];
stable@dpdk.org
Subject: [dpdk-dev] [PATCH v4] eal: fix create user mem map repeatedly when it
exists

From: Yunjian Wang <redacted>

Currently, user mem maps will check if the newly mapped area is adjacent to
any existing mapping, but will not check if the mapping is identical because it
assumes that the API will never get called with the same mapping twice. This
will result in duplicate entries in the user mem maps list.

Fix it by also checking for duplicate mappings, and skipping them if they are
found.

Fixes: 0cbce3a167f1 ("vfio: skip DMA map failure if already mapped")
Cc: stable@dpdk.org

Signed-off-by: Yunjian Wang <redacted>
Acked-by: Anatoly Burakov <redacted>
---
v4:
  Update commit log suggested by Anatoly Burakov
---
 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

050082444e..0967215783 100644

--- a/lib/librte_eal/linux/eal_vfio.c
+++ b/lib/librte_eal/linux/eal_vfio.c

@@ -168,6 +168,10 @@ 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) @@ -175,6 +179,7 @@
merge_map(struct user_mem_map *left, struct user_mem_map *right)

 	left->len += right->len;

+out:
 	memset(right, 0, sizeof(*right));

 	return 1;
--
2.23.0