From cecaa76b2919aac2aa584ce476e9fcd5b084add5 Mon Sep 17 00:00:00 2001
From: Frank de Brabander <debrabander@gmail.com>
Date: Fri, 5 Jul 2019 13:43:14 +0200
Subject: [PATCH] selftests: txring_overwrite: fix incorrect test of mmap()
return value
If mmap() fails it returns MAP_FAILED, which is defined as ((void *) -1).
The current if-statement incorrectly tests if *ring is NULL.
Fixes: 358be656406d ("selftests/net: add txring_overwrite")
Signed-off-by: Frank de Brabander <debrabander@gmail.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
tools/testing/selftests/net/txring_overwrite.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/net/txring_overwrite.c b/tools/testing/selftests/net/txring_overwrite.c
index fd8b1c663c391..7d9ea039450a3 100644
--- a/tools/testing/selftests/net/txring_overwrite.c
+++ b/tools/testing/selftests/net/txring_overwrite.c
@@ -113,7 +113,7 @@ static int setup_tx(char **ring)
*ring = mmap(0, req.tp_block_size * req.tp_block_nr,
PROT_READ | PROT_WRITE, MAP_SHARED, fdt, 0);
- if (!*ring)
+ if (*ring == MAP_FAILED)
error(1, errno, "mmap");
return fdt;
--
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