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From:   John Hubbard <jhubbard@nvidia.com>
To:     Andrew Morton <akpm@linux-foundation.org>
CC:     David Hildenbrand <david@redhat.com>, Peter Xu <peterx@redhat.com>,
        "Shuah Khan" <shuah@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>, <linux-mm@kvack.org>,
        <linux-kselftest@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        John Hubbard <jhubbard@nvidia.com>
Subject: [PATCH v3 09/11] selftests/mm: move certain uffd*() routines from vm_util.c to uffd-common.c
Date:   Tue, 6 Jun 2023 00:16:35 -0700
Message-ID: <20230606071637.267103-10-jhubbard@nvidia.com>
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References: <20230606071637.267103-1-jhubbard@nvidia.com>
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There are only three uffd*() routines that are used outside of the uffd
selftests. Leave these in vm_util.c, where they are available to any mm
selftest program:

    uffd_register()
    uffd_unregister()
    uffd_register_with_ioctls().

A few other uffd*() routines, however, are only used by the uffd-focused
tests found in uffd-stress.c and uffd-unit-tests.c. Move those routines
into uffd-common.c.

Cc: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/mm/uffd-common.c | 59 ++++++++++++++++++++++++
 tools/testing/selftests/mm/uffd-common.h |  5 ++
 tools/testing/selftests/mm/vm_util.c     | 59 ------------------------
 tools/testing/selftests/mm/vm_util.h     |  4 --
 4 files changed, 64 insertions(+), 63 deletions(-)

diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c
index 61c6250adf93..ba20d7504022 100644
--- a/tools/testing/selftests/mm/uffd-common.c
+++ b/tools/testing/selftests/mm/uffd-common.c
@@ -616,3 +616,62 @@ int copy_page(int ufd, unsigned long offset, bool wp)
 {
 	return __copy_page(ufd, offset, false, wp);
 }
+
+int uffd_open_dev(unsigned int flags)
+{
+	int fd, uffd;
+
+	fd = open("/dev/userfaultfd", O_RDWR | O_CLOEXEC);
+	if (fd < 0)
+		return fd;
+	uffd = ioctl(fd, USERFAULTFD_IOC_NEW, flags);
+	close(fd);
+
+	return uffd;
+}
+
+int uffd_open_sys(unsigned int flags)
+{
+#ifdef __NR_userfaultfd
+	return syscall(__NR_userfaultfd, flags);
+#else
+	return -1;
+#endif
+}
+
+int uffd_open(unsigned int flags)
+{
+	int uffd = uffd_open_sys(flags);
+
+	if (uffd < 0)
+		uffd = uffd_open_dev(flags);
+
+	return uffd;
+}
+
+int uffd_get_features(uint64_t *features)
+{
+	struct uffdio_api uffdio_api = { .api = UFFD_API, .features = 0 };
+	/*
+	 * This should by default work in most kernels; the feature list
+	 * will be the same no matter what we pass in here.
+	 */
+	int fd = uffd_open(UFFD_USER_MODE_ONLY);
+
+	if (fd < 0)
+		/* Maybe the kernel is older than user-only mode? */
+		fd = uffd_open(0);
+
+	if (fd < 0)
+		return fd;
+
+	if (ioctl(fd, UFFDIO_API, &uffdio_api)) {
+		close(fd);
+		return -errno;
+	}
+
+	*features = uffdio_api.features;
+	close(fd);
+
+	return 0;
+}
diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h
index 6068f2346b86..197f5262fe0d 100644
--- a/tools/testing/selftests/mm/uffd-common.h
+++ b/tools/testing/selftests/mm/uffd-common.h
@@ -110,6 +110,11 @@ int __copy_page(int ufd, unsigned long offset, bool retry, bool wp);
 int copy_page(int ufd, unsigned long offset, bool wp);
 void *uffd_poll_thread(void *arg);
 
+int uffd_open_dev(unsigned int flags);
+int uffd_open_sys(unsigned int flags);
+int uffd_open(unsigned int flags);
+int uffd_get_features(uint64_t *features);
+
 #define TEST_ANON	1
 #define TEST_HUGETLB	2
 #define TEST_SHMEM	3
diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index 9b06a5034808..681277615839 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -242,62 +242,3 @@ int uffd_unregister(int uffd, void *addr, uint64_t len)
 
 	return ret;
 }
-
-int uffd_open_dev(unsigned int flags)
-{
-	int fd, uffd;
-
-	fd = open("/dev/userfaultfd", O_RDWR | O_CLOEXEC);
-	if (fd < 0)
-		return fd;
-	uffd = ioctl(fd, USERFAULTFD_IOC_NEW, flags);
-	close(fd);
-
-	return uffd;
-}
-
-int uffd_open_sys(unsigned int flags)
-{
-#ifdef __NR_userfaultfd
-	return syscall(__NR_userfaultfd, flags);
-#else
-	return -1;
-#endif
-}
-
-int uffd_open(unsigned int flags)
-{
-	int uffd = uffd_open_sys(flags);
-
-	if (uffd < 0)
-		uffd = uffd_open_dev(flags);
-
-	return uffd;
-}
-
-int uffd_get_features(uint64_t *features)
-{
-	struct uffdio_api uffdio_api = { .api = UFFD_API, .features = 0 };
-	/*
-	 * This should by default work in most kernels; the feature list
-	 * will be the same no matter what we pass in here.
-	 */
-	int fd = uffd_open(UFFD_USER_MODE_ONLY);
-
-	if (fd < 0)
-		/* Maybe the kernel is older than user-only mode? */
-		fd = uffd_open(0);
-
-	if (fd < 0)
-		return fd;
-
-	if (ioctl(fd, UFFDIO_API, &uffdio_api)) {
-		close(fd);
-		return -errno;
-	}
-
-	*features = uffdio_api.features;
-	close(fd);
-
-	return 0;
-}
diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h
index 07f39ed2efba..c2d4ff798b91 100644
--- a/tools/testing/selftests/mm/vm_util.h
+++ b/tools/testing/selftests/mm/vm_util.h
@@ -48,10 +48,6 @@ unsigned long default_huge_page_size(void);
 int uffd_register(int uffd, void *addr, uint64_t len,
 		  bool miss, bool wp, bool minor);
 int uffd_unregister(int uffd, void *addr, uint64_t len);
-int uffd_open_dev(unsigned int flags);
-int uffd_open_sys(unsigned int flags);
-int uffd_open(unsigned int flags);
-int uffd_get_features(uint64_t *features);
 int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len,
 			      bool miss, bool wp, bool minor, uint64_t *ioctls);
 
-- 
2.40.1