Commit 96ed62ea0298 ("mm: page_frag: fix a compile error when kernel
is not compiled") introduced a check to avoid attempting to build
the page_frag module if <linux/page_frag_cache.h> is missing.

Unfortunately this check only works if KDIR points to
/lib/modules/... or an in-tree kernel build. It always fails if KDIR
points to an out-of-tree build (i.e. when the kernel was built with
O=$KDIR make) because only generated headers are present under
$KDIR/include/ in that case.

<linux/page_frag_cache.h> was added more than a year ago (v6.13) so
we can probably live without that check.

Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 tools/testing/selftests/mm/Makefile | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile
index eaf9312097f7..aba51fcac752 100644
--- a/tools/testing/selftests/mm/Makefile
+++ b/tools/testing/selftests/mm/Makefile
@@ -46,12 +46,8 @@ CFLAGS += -U_FORTIFY_SOURCE
 
 KDIR ?= /lib/modules/$(shell uname -r)/build
 ifneq (,$(wildcard $(KDIR)/Module.symvers))
-ifneq (,$(wildcard $(KDIR)/include/linux/page_frag_cache.h))
 TEST_GEN_MODS_DIR := page_frag
 else
-PAGE_FRAG_WARNING = "missing page_frag_cache.h, please use a newer kernel"
-endif
-else
 PAGE_FRAG_WARNING = "missing Module.symvers, please have the kernel built first"
 endif
 
-- 
2.51.2


check_config.sh checks that liburing is available by running the
compiler provided as its first argument. This makes two assumptions:

1. CC consists of only one word
2. No extra flag is required

Unfortunately, there are many situations where these assumptions
don't hold. For instance:

- When using Clang, CC consists of multiple words
- When cross-compiling, extra flags may be required to allow the
  compiler to find headers

Remove these assumptions by passing down CC and CFLAGS as-is from
the Makefile, so that the same command line is used as when actually
building the tests.

Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 tools/testing/selftests/mm/Makefile        | 2 +-
 tools/testing/selftests/mm/check_config.sh | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile
index aba51fcac752..b1c949cd7c3d 100644
--- a/tools/testing/selftests/mm/Makefile
+++ b/tools/testing/selftests/mm/Makefile
@@ -230,7 +230,7 @@ $(OUTPUT)/migration: LDLIBS += -lnuma
 $(OUTPUT)/rmap: LDLIBS += -lnuma
 
 local_config.mk local_config.h: check_config.sh
-	/bin/sh ./check_config.sh $(CC)
+	CC="$(CC)" CFLAGS="$(CFLAGS)" ./check_config.sh
 
 EXTRA_CLEAN += local_config.mk local_config.h
 
diff --git a/tools/testing/selftests/mm/check_config.sh b/tools/testing/selftests/mm/check_config.sh
index 3954f4746161..b84c82bbf875 100755
--- a/tools/testing/selftests/mm/check_config.sh
+++ b/tools/testing/selftests/mm/check_config.sh
@@ -16,8 +16,7 @@ echo "#include <sys/types.h>"        > $tmpfile_c
 echo "#include <liburing.h>"        >> $tmpfile_c
 echo "int func(void) { return 0; }" >> $tmpfile_c
 
-CC=${1:?"Usage: $0 <compiler> # example compiler: gcc"}
-$CC -c $tmpfile_c -o $tmpfile_o >/dev/null 2>&1
+$CC $CFLAGS -c $tmpfile_c -o $tmpfile_o
 
 if [ -f $tmpfile_o ]; then
     echo "#define LOCAL_CONFIG_HAVE_LIBURING 1"  > $OUTPUT_H_FILE
-- 
2.51.2


One of the pagemap_ioctl tests attempts to fault in pages by
memcpy()'ing them to an unused buffer. This probably worked
originally, but since commit 46036188ea1f ("selftests/mm: build with
-O2") the compiler is free to optimise away that unused buffer and
the memcpy() with it. As a result there might not be any resident
page in the mapping and the test may fail.

We don't need to copy all that memory anyway. Just fault in every
page by forcing the compiler to read the first byte.

Cc: Usama Anjum <Usama.Anjum@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 tools/testing/selftests/mm/pagemap_ioctl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c
index 2cb5441f29c7..67a7a3705604 100644
--- a/tools/testing/selftests/mm/pagemap_ioctl.c
+++ b/tools/testing/selftests/mm/pagemap_ioctl.c
@@ -1056,7 +1056,6 @@ int sanity_tests(void)
 	struct page_region *vec;
 	char *mem, *fmem;
 	struct stat sbuf;
-	char *tmp_buf;
 
 	/* 1. wrong operation */
 	mem_size = 10 * page_size;
@@ -1167,8 +1166,9 @@ int sanity_tests(void)
 	if (fmem == MAP_FAILED)
 		ksft_exit_fail_msg("error nomem %d %s\n", errno, strerror(errno));
 
-	tmp_buf = malloc(sbuf.st_size);
-	memcpy(tmp_buf, fmem, sbuf.st_size);
+	/* Fault in every page by reading the first byte */
+	for (i = 0; i < sbuf.st_size; i += page_size)
+		(void)*(volatile char *)(fmem + i);
 
 	ret = pagemap_ioctl(fmem, sbuf.st_size, vec, vec_size, 0, 0,
 			    0, PAGEMAP_NON_WRITTEN_BITS, 0, PAGEMAP_NON_WRITTEN_BITS);
-- 
2.51.2


pagemap_ioctl always reports success, whether the tests succeeded or
not. Call ksft_finished() to report the right status.

While at it also fix the exit code in unexpected situations:

- Report SKIP if userfaultfd isn't available (in line with other
  tests)

- Report FAIL if we failed to open /proc/self/pagemap (returning
  -EINVAL from main() is meaningless)

Cc: Usama Anjum <Usama.Anjum@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 tools/testing/selftests/mm/pagemap_ioctl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c
index 67a7a3705604..aeedb96dfffb 100644
--- a/tools/testing/selftests/mm/pagemap_ioctl.c
+++ b/tools/testing/selftests/mm/pagemap_ioctl.c
@@ -1553,7 +1553,7 @@ int main(int __attribute__((unused)) argc, char *argv[])
 	ksft_print_header();
 
 	if (init_uffd())
-		ksft_exit_pass();
+		ksft_exit_skip("Failed to initialize userfaultfd\n");
 
 	ksft_set_plan(117);
 
@@ -1562,7 +1562,7 @@ int main(int __attribute__((unused)) argc, char *argv[])
 
 	pagemap_fd = open(PAGEMAP, O_RDONLY);
 	if (pagemap_fd < 0)
-		return -EINVAL;
+		ksft_exit_fail_msg("Failed to open " PAGEMAP "\n");
 
 	/* 1. Sanity testing */
 	sanity_tests_sd();
@@ -1734,5 +1734,5 @@ int main(int __attribute__((unused)) argc, char *argv[])
 	zeropfn_tests();
 
 	close(pagemap_fd);
-	ksft_exit_pass();
+	ksft_finished();
 }
-- 
2.51.2