Re: [PATCH linux-next] selftests/vm: calculate variables in correct order

[Peter Xu <peterx@xxxxxxxxxx>]

On Wed, Nov 16, 2022 at 08:09:11PM -0400, Joel Savitz wrote:
> However, I noticed that on the mm-everything branch, the hugepage-mmap test
> fails:
> 
> # ./run_vmtests.sh -t "hugetlb"
> running: ./hugepage-mmap
> -----------------------
> running ./hugepage-mmap
> -----------------------
> Open failed: No such file or directory
> [FAIL]
> ...
> 
> It appears this is due to commit 0796c7b8be84 ("selftests/vm: drop mnt
> point for hugetlb in run_vmtests.sh")
> as the test still replies on the ./huge mountpoint removed in that commit.
> The test passes before that patchset is applied.

Oops, sorry I totally overlooked this hard-coded test case using the
mntpoint.

Fix is simple though, which is attached.

-- 
Peter Xu

>From 71da2480d4bac0fc598e4d1f05f71aba8b980bc4 Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@xxxxxxxxxx>
Date: Thu, 17 Nov 2022 16:29:15 -0500
Subject: [PATCH] selftests/vm: use memfd for hugepage-mmap test
Content-type: text/plain

This test was overlooked with a hard-coded mntpoint path in test when we're
removing the hugetlb mntpoint in commit 0796c7b8be84.  Fix it up so the
test can keep running.

Reported-by: Joel Savitz <jsavitz@xxxxxxxxxx>
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
 tools/testing/selftests/vm/hugepage-mmap.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/vm/hugepage-mmap.c b/tools/testing/selftests/vm/hugepage-mmap.c
index 93f9e7b81331..955ef87f382c 100644
--- a/tools/testing/selftests/vm/hugepage-mmap.c
+++ b/tools/testing/selftests/vm/hugepage-mmap.c
@@ -16,14 +16,13 @@
  * range.
  * Other architectures, such as ppc64, i386 or x86_64 are not so constrained.
  */
-
+#define _GNU_SOURCE
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/mman.h>
 #include <fcntl.h>
 
-#define FILE_NAME "huge/hugepagefile"
 #define LENGTH (256UL*1024*1024)
 #define PROTECTION (PROT_READ | PROT_WRITE)
 
@@ -67,16 +66,16 @@ int main(void)
 	void *addr;
 	int fd, ret;
 
-	fd = open(FILE_NAME, O_CREAT | O_RDWR, 0755);
+	fd = memfd_create("hugepage-mmap", MFD_HUGETLB);
 	if (fd < 0) {
-		perror("Open failed");
+		perror("memfd_create() failed");
 		exit(1);
 	}
 
 	addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, fd, 0);
 	if (addr == MAP_FAILED) {
 		perror("mmap");
-		unlink(FILE_NAME);
+		close(fd);
 		exit(1);
 	}
 
@@ -87,7 +86,6 @@ int main(void)
 
 	munmap(addr, LENGTH);
 	close(fd);
-	unlink(FILE_NAME);
 
 	return ret;
 }
-- 
2.37.3