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From:   Peter Xu <peterx@redhat.com>
To:     linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc:     Mike Kravetz <mike.kravetz@oracle.com>,
        Mike Rapoport <rppt@linux.vnet.ibm.com>,
        Andrea Arcangeli <aarcange@redhat.com>, peterx@redhat.com,
        Leonardo Bras Soares Passos <lsoaresp@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Hildenbrand <david@redhat.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Nadav Amit <nadav.amit@gmail.com>
Subject: [PATCH 20/29] selftests/mm: Allow allocate_area() to fail properly
Date:   Thu, 30 Mar 2023 12:08:15 -0400
Message-Id: <20230330160815.3107534-1-peterx@redhat.com>
In-Reply-To: <20230330155707.3106228-1-peterx@redhat.com>
References: <20230330155707.3106228-1-peterx@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Mostly to detect hugetlb allocation errors and skip hugetlb tests when
pages are not allocated.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 tools/testing/selftests/mm/uffd-common.c | 32 +++++++++++++++++-------
 tools/testing/selftests/mm/uffd-common.h |  4 +--
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c
index 92b7e00efa8a..ae6b61144b53 100644
--- a/tools/testing/selftests/mm/uffd-common.c
+++ b/tools/testing/selftests/mm/uffd-common.c
@@ -44,10 +44,13 @@ static void anon_release_pages(char *rel_area)
 		err("madvise(MADV_DONTNEED) failed");
 }
 
-static void anon_allocate_area(void **alloc_area, bool is_src)
+static int anon_allocate_area(void **alloc_area, bool is_src)
 {
 	*alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 			   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (*alloc_area == MAP_FAILED)
+		err("ENOMEM");
+	return 0;
 }
 
 static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
@@ -65,7 +68,7 @@ static void hugetlb_release_pages(char *rel_area)
 	}
 }
 
-static void hugetlb_allocate_area(void **alloc_area, bool is_src)
+static int hugetlb_allocate_area(void **alloc_area, bool is_src)
 {
 	off_t size = nr_pages * page_size;
 	off_t offset = is_src ? 0 : size;
@@ -77,14 +80,16 @@ static void hugetlb_allocate_area(void **alloc_area, bool is_src)
 			   (map_shared ? MAP_SHARED : MAP_PRIVATE) |
 			   (is_src ? 0 : MAP_NORESERVE),
 			   mem_fd, offset);
-	if (*alloc_area == MAP_FAILED)
-		err("mmap of hugetlbfs file failed");
+	if (*alloc_area == MAP_FAILED) {
+		*alloc_area = NULL;
+		return -errno;
+	}
 
 	if (map_shared) {
 		area_alias = mmap(NULL, size, PROT_READ | PROT_WRITE,
 				  MAP_SHARED, mem_fd, offset);
 		if (area_alias == MAP_FAILED)
-			err("mmap of hugetlb file alias failed");
+			return -errno;
 	}
 
 	if (is_src) {
@@ -96,6 +101,7 @@ static void hugetlb_allocate_area(void **alloc_area, bool is_src)
 		*alloc_area_alias = area_alias;
 
 	close(mem_fd);
+	return 0;
 }
 
 static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
@@ -112,7 +118,7 @@ static void shmem_release_pages(char *rel_area)
 		err("madvise(MADV_REMOVE) failed");
 }
 
-static void shmem_allocate_area(void **alloc_area, bool is_src)
+static int shmem_allocate_area(void **alloc_area, bool is_src)
 {
 	void *area_alias = NULL;
 	size_t bytes = nr_pages * page_size, hpage_size = read_pmd_pagesize();
@@ -150,6 +156,7 @@ static void shmem_allocate_area(void **alloc_area, bool is_src)
 		area_dst_alias = area_alias;
 
 	close(mem_fd);
+	return 0;
 }
 
 static void shmem_alias_mapping(__u64 *start, size_t len, unsigned long offset)
@@ -282,14 +289,19 @@ static void uffd_test_ctx_clear(void)
 	munmap_area((void **)&area_remap);
 }
 
-void uffd_test_ctx_init(uint64_t features)
+int uffd_test_ctx_init(uint64_t features)
 {
 	unsigned long nr, cpu;
+	int ret;
 
 	uffd_test_ctx_clear();
 
-	uffd_test_ops->allocate_area((void **)&area_src, true);
-	uffd_test_ops->allocate_area((void **)&area_dst, false);
+	ret = uffd_test_ops->allocate_area((void **)&area_src, true);
+	if (ret)
+		return ret;
+	ret = uffd_test_ops->allocate_area((void **)&area_dst, false);
+	if (ret)
+		return ret;
 
 	userfaultfd_open(&features);
 
@@ -337,6 +349,8 @@ void uffd_test_ctx_init(uint64_t features)
 	for (cpu = 0; cpu < nr_cpus; cpu++)
 		if (pipe2(&pipefd[cpu * 2], O_CLOEXEC | O_NONBLOCK))
 			err("pipe");
+
+	return 0;
 }
 
 void wp_range(int ufd, __u64 start, __u64 len, bool wp)
diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h
index f4bc73ce3b48..51ec75f6d0c1 100644
--- a/tools/testing/selftests/mm/uffd-common.h
+++ b/tools/testing/selftests/mm/uffd-common.h
@@ -80,7 +80,7 @@ struct uffd_stats {
 };
 
 struct uffd_test_ops {
-	void (*allocate_area)(void **alloc_area, bool is_src);
+	int (*allocate_area)(void **alloc_area, bool is_src);
 	void (*release_pages)(char *rel_area);
 	void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
 	void (*check_pmd_mapping)(void *p, int expect_nr_hpages);
@@ -101,7 +101,7 @@ extern uffd_test_ops_t hugetlb_uffd_test_ops;
 extern uffd_test_ops_t *uffd_test_ops;
 
 void uffd_stats_report(struct uffd_stats *stats, int n_cpus);
-void uffd_test_ctx_init(uint64_t features);
+int uffd_test_ctx_init(uint64_t features);
 void userfaultfd_open(uint64_t *features);
 int uffd_read_msg(int ufd, struct uffd_msg *msg);
 void wp_range(int ufd, __u64 start, __u64 len, bool wp);
-- 
2.39.1