[PATCH 2/8] selftests/vm: use a common gup_test.h

John Hubbard
2020-09-28T06:22:02Z

Avoid the need to copy-paste the gup_test ioctl commands and the struct
gup_test definition, between the kernel and the user space application,
by providing a new header file for these. This allows easier and safer
adding of new ioctl calls, as well as reducing the overall line count.

Details: The header file has to be able to compile independently,
because of the arguably unfortunate way that the Makefile is written:
the Makefile tries to build all of its prerequisites, when really it
should be only building the .c files, and leaving the other
prerequisites (LOCAL_HDRS) as pure dependencies.

That Makefile limitation is probably not worth fixing, but it explains
why one of the includes had to be moved into the new header file.

Also: simplify the ioctl struct (struct gup_test), by deleting the
unused __expansion[10] field. This sort of thing is what you might see
in a stable ABI, but this low-level, kernel-developer-oriented
selftests/vm system is very much not subject to ABI stability. So
"expansion" and "reserved" fields are unnecessary here.

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
mm/gup_test.c | 17 +----------------
mm/gup_test.h | 22 ++++++++++++++++++++++
tools/testing/selftests/vm/Makefile | 2 ++
tools/testing/selftests/vm/gup_test.c | 22 +---------------------
4 files changed, 26 insertions(+), 37 deletions(-)
create mode 100644 mm/gup_test.h

diff --git a/mm/gup_test.c b/mm/gup_test.c
index 10f41c0528de..a3c86d0fdff7 100644
--- a/mm/gup_test.c
+++ b/mm/gup_test.c
@@ -4,22 +4,7 @@
#include <linux/uaccess.h>
#include <linux/ktime.h>
#include <linux/debugfs.h>
-
-#define GUP_FAST_BENCHMARK _IOWR('g', 1, struct gup_test)
-#define GUP_BENCHMARK _IOWR('g', 2, struct gup_test)
-#define PIN_FAST_BENCHMARK _IOWR('g', 3, struct gup_test)
-#define PIN_BENCHMARK _IOWR('g', 4, struct gup_test)
-#define PIN_LONGTERM_BENCHMARK _IOWR('g', 5, struct gup_test)
-
-struct gup_test {
- __u64 get_delta_usec;
- __u64 put_delta_usec;
- __u64 addr;
- __u64 size;
- __u32 nr_pages_per_call;
- __u32 flags;
- __u64 expansion[10]; /* For future use */
-};
+#include "gup_test.h"

static void put_back_pages(unsigned int cmd, struct page **pages,
unsigned long nr_pages)
diff --git a/mm/gup_test.h b/mm/gup_test.h
new file mode 100644
index 000000000000..931c2f3f477a
--- /dev/null
+++ b/mm/gup_test.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __GUP_TEST_H
+#define __GUP_TEST_H
+
+#include <linux/types.h>
+
+#define GUP_FAST_BENCHMARK _IOWR('g', 1, struct gup_test)
+#define GUP_BENCHMARK _IOWR('g', 2, struct gup_test)
+#define PIN_FAST_BENCHMARK _IOWR('g', 3, struct gup_test)
+#define PIN_BENCHMARK _IOWR('g', 4, struct gup_test)
+#define PIN_LONGTERM_BENCHMARK _IOWR('g', 5, struct gup_test)
+
+struct gup_test {
+ __u64 get_delta_usec;
+ __u64 put_delta_usec;
+ __u64 addr;
+ __u64 size;
+ __u32 nr_pages_per_call;
+ __u32 flags;
+};
+
+#endif /* __GUP_TEST_H */
diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index d1ae706d9927..9cc6bc087461 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -130,3 +130,5 @@ endif
$(OUTPUT)/userfaultfd: LDLIBS += -lpthread

$(OUTPUT)/mlock-random-test: LDLIBS += -lcap
+
+$(OUTPUT)/gup_test: ../../../../mm/gup_test.h
diff --git a/tools/testing/selftests/vm/gup_test.c b/tools/testing/selftests/vm/gup_test.c
index e930135727a2..70db259582c3 100644
--- a/tools/testing/selftests/vm/gup_test.c
+++ b/tools/testing/selftests/vm/gup_test.c
@@ -2,39 +2,19 @@
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
-
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/types.h>
-
-#include <linux/types.h>
+#include "../../../../mm/gup_test.h"

#define MB (1UL << 20)
#define PAGE_SIZE sysconf(_SC_PAGESIZE)

-#define GUP_FAST_BENCHMARK _IOWR('g', 1, struct gup_test)
-#define GUP_BENCHMARK _IOWR('g', 2, struct gup_test)
-
-/* Similar to above, but use FOLL_PIN instead of FOLL_GET. */
-#define PIN_FAST_BENCHMARK _IOWR('g', 3, struct gup_test)
-#define PIN_BENCHMARK _IOWR('g', 4, struct gup_test)
-#define PIN_LONGTERM_BENCHMARK _IOWR('g', 5, struct gup_test)
-
/* Just the flags we need, copied from mm.h: */
#define FOLL_WRITE 0x01 /* check pte is writable */

-struct gup_test {
- __u64 get_delta_usec;
- __u64 put_delta_usec;
- __u64 addr;
- __u64 size;
- __u32 nr_pages_per_call;
- __u32 flags;
- __u64 expansion[10]; /* For future use */
-};
-
int main(int argc, char **argv)
{
struct gup_test gup;
--
2.28.0