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Message-ID: <CAEjAshqiaxkxk=Y_Du1rX-ULV1e0DeTWdHRiXz_uyADL8VeAog@mail.gmail.com>
Date: Thu, 23 Mar 2017 10:09:29 +0900
From: SeongJae Park <sj38.park@...il.com>
To: shuah@...nel.org
Cc: Simon Guo <wei.guo.simon@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
linux-kselftest@...r.kernel.org,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
SeongJae Park <sj38.park@...il.com>
Subject: Re: [PATCH] selftests/vm: Set mmap()'s fd as -1 for MAP_ANONYMOUS flag
Hello Shuah,
May I ask some comments?
Thanks,
SeongJae Park
On Wed, Mar 15, 2017 at 10:19 PM, SeongJae Park <sj38.park@...il.com> wrote:
> Man page of mmap() says that portable applications should ensure fd
> argument to be -1 if MAP_ANONYMOUS flag is set as below:
> ```
> The mapping is not backed by any file; its contents are initialized to
> zero. The fd and offset arguments are ignored; however, some
> implementations require fd to be -1 if MAP_ANONYMOUS (or
> MAP_ANON) is specified, and portable applications
> should ensure this.
> ```
>
> However, few mmap() calls under selftests/vm/ uses 0 as fd though they
> use MAP_ANONYMOUS flag. This commit changes the argument to be -1 as
> recommended.
>
> Signed-off-by: SeongJae Park <sj38.park@...il.com>
> ---
> tools/testing/selftests/vm/map_hugetlb.c | 2 +-
> tools/testing/selftests/vm/mlock2-tests.c | 12 ++++++------
> tools/testing/selftests/vm/on-fault-limit.c | 2 +-
> tools/testing/selftests/vm/thuge-gen.c | 2 +-
> 4 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/tools/testing/selftests/vm/map_hugetlb.c b/tools/testing/selftests/vm/map_hugetlb.c
> index addcd6fc1ecc..77687ab59f77 100644
> --- a/tools/testing/selftests/vm/map_hugetlb.c
> +++ b/tools/testing/selftests/vm/map_hugetlb.c
> @@ -62,7 +62,7 @@ int main(void)
> void *addr;
> int ret;
>
> - addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, 0, 0);
> + addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, -1, 0);
> if (addr == MAP_FAILED) {
> perror("mmap");
> exit(1);
> diff --git a/tools/testing/selftests/vm/mlock2-tests.c b/tools/testing/selftests/vm/mlock2-tests.c
> index ff0cda2b19c9..e5dbc87b4297 100644
> --- a/tools/testing/selftests/vm/mlock2-tests.c
> +++ b/tools/testing/selftests/vm/mlock2-tests.c
> @@ -293,7 +293,7 @@ static int test_mlock_lock()
> unsigned long page_size = getpagesize();
>
> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> if (map == MAP_FAILED) {
> perror("test_mlock_locked mmap");
> goto out;
> @@ -402,7 +402,7 @@ static int test_mlock_onfault()
> unsigned long page_size = getpagesize();
>
> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> if (map == MAP_FAILED) {
> perror("test_mlock_locked mmap");
> goto out;
> @@ -445,7 +445,7 @@ static int test_lock_onfault_of_present()
> uint64_t page1_flags, page2_flags;
>
> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> if (map == MAP_FAILED) {
> perror("test_mlock_locked mmap");
> goto out;
> @@ -492,7 +492,7 @@ static int test_munlockall()
> unsigned long page_size = getpagesize();
>
> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>
> if (map == MAP_FAILED) {
> perror("test_munlockall mmap");
> @@ -518,7 +518,7 @@ static int test_munlockall()
> munmap(map, 2 * page_size);
>
> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>
> if (map == MAP_FAILED) {
> perror("test_munlockall second mmap");
> @@ -573,7 +573,7 @@ static int test_vma_management(bool call_mlock)
> struct vm_boundaries page3;
>
> map = mmap(NULL, 3 * page_size, PROT_READ | PROT_WRITE,
> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> if (map == MAP_FAILED) {
> perror("mmap()");
> return ret;
> diff --git a/tools/testing/selftests/vm/on-fault-limit.c b/tools/testing/selftests/vm/on-fault-limit.c
> index 0ae458f32fdb..7f96a5c2e292 100644
> --- a/tools/testing/selftests/vm/on-fault-limit.c
> +++ b/tools/testing/selftests/vm/on-fault-limit.c
> @@ -26,7 +26,7 @@ static int test_limit(void)
> }
>
> map = mmap(NULL, 2 * lims.rlim_max, PROT_READ | PROT_WRITE,
> - MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, 0, 0);
> + MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);
> if (map != MAP_FAILED)
> printf("mmap should have failed, but didn't\n");
> else {
> diff --git a/tools/testing/selftests/vm/thuge-gen.c b/tools/testing/selftests/vm/thuge-gen.c
> index 0bc737a75150..88a2ab535e01 100644
> --- a/tools/testing/selftests/vm/thuge-gen.c
> +++ b/tools/testing/selftests/vm/thuge-gen.c
> @@ -146,7 +146,7 @@ void test_mmap(unsigned long size, unsigned flags)
>
> before = read_free(size);
> map = mmap(NULL, size*NUM_PAGES, PROT_READ|PROT_WRITE,
> - MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, 0, 0);
> + MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, -1, 0);
>
> if (map == (char *)-1) err("mmap");
> memset(map, 0xff, size*NUM_PAGES);
> --
> 2.10.0
>
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