selftests/mm: merge map_hugetlb into hugepage-mmap

Both tests create a hugettlb mapping, fill it with data and verify the
data, the only difference is that one uses file-backed memory and another
one uses anonymous memory.

Merge both tests into a single file.

Link: https://lore.kernel.org/20260511162840.375890-7-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/admin-guide/mm/hugetlbpage.rst

@@ -455,7 +455,7 @@ used to change the file attributes on hugetlbfs.
 Also, it is important to note that no such mount command is required if
 applications are going to use only shmat/shmget system calls or mmap with
 MAP_HUGETLB.  For an example of how to use mmap with MAP_HUGETLB see
-:ref:`map_hugetlb <map_hugetlb>` below.
+:ref:`examples <examples>` below.
 
 Users who wish to use hugetlb memory via shared memory segment should be
 members of a supplementary group and system admin needs to configure that gid
@@ -473,10 +473,7 @@ a hugetlb page and the length is smaller than the hugepage size.
 Examples
 ========
 
-.. _map_hugetlb:
-
-``map_hugetlb``
-	see tools/testing/selftests/mm/map_hugetlb.c
+.. _examples:
 
 ``hugepage-shm``
 	see tools/testing/selftests/mm/hugepage-shm.c

tools/testing/selftests/mm/Makefile

@@ -70,7 +70,6 @@ TEST_GEN_FILES += hugepage-vmemmap
 TEST_GEN_FILES += khugepaged
 TEST_GEN_FILES += madv_populate
 TEST_GEN_FILES += map_fixed_noreplace
-TEST_GEN_FILES += map_hugetlb
 TEST_GEN_FILES += map_populate
 ifneq (,$(filter $(ARCH),arm64 riscv riscv64 x86 x86_64 loongarch32 loongarch64))
 TEST_GEN_FILES += memfd_secret

tools/testing/selftests/mm/hugepage-mmap.c

@@ -15,6 +15,8 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <fcntl.h>
+#include <linux/memfd.h>
+#include "vm_util.h"
 #include "kselftest.h"
 
 #define LENGTH (256UL*1024*1024)
@@ -25,54 +27,109 @@ static void check_bytes(char *addr)
 	ksft_print_msg("First hex is %x\n", *((unsigned int *)addr));
 }
 
-static void write_bytes(char *addr)
+static void write_bytes(char *addr, size_t length)
 {
 	unsigned long i;
 
-	for (i = 0; i < LENGTH; i++)
+	for (i = 0; i < length; i++)
 		*(addr + i) = (char)i;
 }
 
-static int read_bytes(char *addr)
+static bool verify_bytes(char *addr, size_t length)
 {
 	unsigned long i;
 
 	check_bytes(addr);
-	for (i = 0; i < LENGTH; i++)
+	for (i = 0; i < length; i++)
 		if (*(addr + i) != (char)i) {
-			ksft_print_msg("Error: Mismatch at %lu\n", i);
-			return 1;
+			ksft_print_msg("Error: Mismatch at %lu(%p)\n", i, addr);
+			return false;
 		}
-	return 0;
+
+	return true;
 }
 
-int main(void)
+static void test_mmap(size_t length, int mmap_flags, int fd,
+		      const char *test_name)
 {
+	bool passed = true;
 	void *addr;
-	int fd, ret;
 
-	ksft_print_header();
-	ksft_set_plan(1);
-
-	fd = memfd_create("hugepage-mmap", MFD_HUGETLB);
-	if (fd < 0)
-		ksft_exit_fail_msg("memfd_create() failed: %s\n", strerror(errno));
-
-	addr = mmap(NULL, LENGTH, PROTECTION, MAP_SHARED, fd, 0);
-	if (addr == MAP_FAILED) {
-		close(fd);
-		ksft_exit_fail_msg("mmap(): %s\n", strerror(errno));
-	}
+	addr = mmap(NULL, length, PROTECTION, mmap_flags, fd, 0);
+	if (addr == MAP_FAILED)
+		ksft_exit_fail_perror("mmap");
 
 	ksft_print_msg("Returned address is %p\n", addr);
 	check_bytes(addr);
-	write_bytes(addr);
-	ret = read_bytes(addr);
+	write_bytes(addr, length);
+	if (!verify_bytes(addr, length))
+		passed = false;
 
-	munmap(addr, LENGTH);
-	close(fd);
+	/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
+	if (munmap(addr, length))
+		ksft_exit_fail_perror("munmap");
 
-	ksft_test_result(!ret, "Read same data\n");
-
-	ksft_exit(!ret);
+	ksft_test_result(passed, "%s\n", test_name);
+}
+
+static void test_anon_mmap(size_t length, int shift)
+{
+	const char *test_name = "hugetlb anonymous mmap";
+	int mmap_flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB;
+
+	if (shift)
+		mmap_flags |= (shift & MAP_HUGE_MASK) << MAP_HUGE_SHIFT;
+
+	test_mmap(length, mmap_flags, -1, test_name);
+}
+
+static void test_file_mmap(size_t length, int shift)
+{
+	const char *test_name = "hugetlb file mmap";
+	int mfd_flags = MFD_HUGETLB;
+	int fd;
+
+	if (shift)
+		mfd_flags |= (shift & MFD_HUGE_MASK) << MFD_HUGE_SHIFT;
+
+	fd = memfd_create("hugetlb-mmap", mfd_flags);
+	if (fd < 0)
+		ksft_exit_fail_perror("memfd_create");
+
+	test_mmap(length, MAP_SHARED, fd, test_name);
+	close(fd);
+}
+
+int main(int argc, char **argv)
+{
+	size_t hugepage_size;
+	size_t length = LENGTH;
+	int shift = 0;
+
+	ksft_print_header();
+	ksft_set_plan(2);
+
+	if (argc > 1)
+		length = atol(argv[1]) << 20;
+	if (argc > 2)
+		shift = atoi(argv[2]);
+
+	if (shift) {
+		hugepage_size = (1UL << shift);
+		ksft_print_msg("%lu kB hugepages\n", 1UL << (shift - 10));
+	} else {
+		hugepage_size = default_huge_page_size();
+		ksft_print_msg("Default size hugepages (%lu kB)\n", hugepage_size >> 10);
+	}
+
+	/* munmap will fail if the length is not page aligned */
+	if (hugepage_size > length)
+		length = hugepage_size;
+
+	ksft_print_msg("Mapping %lu Mbytes\n", (unsigned long)length >> 20);
+
+	test_anon_mmap(length, shift);
+	test_file_mmap(length, shift);
+
+	ksft_finished();
 }

tools/testing/selftests/mm/map_hugetlb.c

@@ -1,88 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Example of using hugepage memory in a user application using the mmap
- * system call with MAP_HUGETLB flag.  Before running this program make
- * sure the administrator has allocated enough default sized huge pages
- * to cover the 256 MB allocation.
- */
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-#include "vm_util.h"
-#include "kselftest.h"
-
-#define LENGTH (256UL*1024*1024)
-#define PROTECTION (PROT_READ | PROT_WRITE)
-
-static void check_bytes(char *addr)
-{
-	ksft_print_msg("First hex is %x\n", *((unsigned int *)addr));
-}
-
-static void write_bytes(char *addr, size_t length)
-{
-	unsigned long i;
-
-	for (i = 0; i < length; i++)
-		*(addr + i) = (char)i;
-}
-
-static void read_bytes(char *addr, size_t length)
-{
-	unsigned long i;
-
-	check_bytes(addr);
-	for (i = 0; i < length; i++)
-		if (*(addr + i) != (char)i)
-			ksft_exit_fail_msg("Mismatch at %lu\n", i);
-
-	ksft_test_result_pass("Read correct data\n");
-}
-
-int main(int argc, char **argv)
-{
-	void *addr;
-	size_t hugepage_size;
-	size_t length = LENGTH;
-	int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB;
-	int shift = 0;
-
-	hugepage_size = default_huge_page_size();
-	/* munmap with fail if the length is not page aligned */
-	if (hugepage_size > length)
-		length = hugepage_size;
-
-	ksft_print_header();
-	ksft_set_plan(1);
-
-	if (argc > 1)
-		length = atol(argv[1]) << 20;
-	if (argc > 2) {
-		shift = atoi(argv[2]);
-		if (shift)
-			flags |= (shift & MAP_HUGE_MASK) << MAP_HUGE_SHIFT;
-	}
-
-	if (shift)
-		ksft_print_msg("%u kB hugepages\n", 1 << (shift - 10));
-	else
-		ksft_print_msg("Default size hugepages\n");
-	ksft_print_msg("Mapping %lu Mbytes\n", (unsigned long)length >> 20);
-
-	addr = mmap(NULL, length, PROTECTION, flags, -1, 0);
-	if (addr == MAP_FAILED)
-		ksft_exit_fail_msg("mmap: %s\n", strerror(errno));
-
-	ksft_print_msg("Returned address is %p\n", addr);
-	check_bytes(addr);
-	write_bytes(addr, length);
-	read_bytes(addr, length);
-
-	/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
-	if (munmap(addr, length))
-		ksft_exit_fail_msg("munmap: %s\n", strerror(errno));
-
-	ksft_finished();
-}

tools/testing/selftests/mm/run_vmtests.sh

@@ -292,7 +292,6 @@ CATEGORY="hugetlb" run_test ./hugepage-shm
 echo "$shmmax" > /proc/sys/kernel/shmmax
 echo "$shmall" > /proc/sys/kernel/shmall
 
-CATEGORY="hugetlb" run_test ./map_hugetlb
 CATEGORY="hugetlb" run_test ./hugepage-mremap
 CATEGORY="hugetlb" run_test ./hugepage-vmemmap
 CATEGORY="hugetlb" run_test ./hugetlb-madvise