[PATCH v3 0/3] Restore the kernel v5.13 text attribute write behavior

[PATCH v3 0/3] Restore the kernel v5.13 text attribute write behavior

[Bart Van Assche]

Hi Christoph,

This patch series restores the v5.13 text attribute write behavior and also
adds unit tests for configfs. Please consider these patches for inclusion in
the Linux kernel.

Thanks,

Bart.

Changes compared to v2:
- Modified description of patch 2/3.

Changes compared to v1:
- Instead of making the text attribute write behavior POSIX compliant, restore
  the v5.13 behavior.
- Added more unit tests.

Bart Van Assche (3):
  configfs: Restore the kernel v5.13 text attribute write behavior
  kunit: Add support for suite initialization and cleanup
  configfs: Add unit tests

 fs/configfs/Kconfig         |   8 +
 fs/configfs/Makefile        |   2 +
 fs/configfs/configfs-test.c | 427 ++++++++++++++++++++++++++++++++++++
 fs/configfs/file.c          |  18 +-
 include/kunit/test.h        |   4 +
 lib/kunit/test.c            |  14 ++
 6 files changed, 461 insertions(+), 12 deletions(-)
 create mode 100644 fs/configfs/configfs-test.c

[PATCH v3 1/3] configfs: Restore the kernel v5.13 text attribute write behavior

[Bart Van Assche]

Instead of appending new text attribute data at the offset specified by the
write() system call, only pass the newly written data to the .store()
callback.

Cc: Bodo Stroesser <bostroesser@gmail.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Yanko Kaneti <yaneti@declera.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Reported-by: Bodo Stroesser <bostroesser@gmail.com>
Tested-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 fs/configfs/file.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index 5a0be9985bae..0ad32150611e 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -177,28 +177,22 @@ static ssize_t configfs_bin_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	return retval;
 }
 
-/* Fill [buffer, buffer + pos) with data coming from @from. */
-static int fill_write_buffer(struct configfs_buffer *buffer, loff_t pos,
+/* Fill @buffer with data coming from @from. */
+static int fill_write_buffer(struct configfs_buffer *buffer,
 			     struct iov_iter *from)
 {
-	loff_t to_copy;
 	int copied;
-	u8 *to;
 
 	if (!buffer->page)
 		buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0);
 	if (!buffer->page)
 		return -ENOMEM;
 
-	to_copy = SIMPLE_ATTR_SIZE - 1 - pos;
-	if (to_copy <= 0)
-		return 0;
-	to = buffer->page + pos;
-	copied = copy_from_iter(to, to_copy, from);
+	copied = copy_from_iter(buffer->page, SIMPLE_ATTR_SIZE - 1, from);
 	buffer->needs_read_fill = 1;
 	/* if buf is assumed to contain a string, terminate it by \0,
 	 * so e.g. sscanf() can scan the string easily */
-	to[copied] = 0;
+	buffer->page[copied] = 0;
 	return copied ? : -EFAULT;
 }
 
@@ -227,10 +221,10 @@ static ssize_t configfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct configfs_buffer *buffer = file->private_data;
-	ssize_t len;
+	int len;
 
 	mutex_lock(&buffer->mutex);
-	len = fill_write_buffer(buffer, iocb->ki_pos, from);
+	len = fill_write_buffer(buffer, from);
 	if (len > 0)
 		len = flush_write_buffer(file, buffer, len);
 	if (len > 0)

[PATCH v3 2/3] kunit: Add support for suite initialization and cleanup

[Bart Van Assche]

A common feature of unit testing frameworks is support for sharing a test
configuration across multiple unit tests. Add this functionality to the
KUnit framework. This functionality will be used in the next patch in this
series.

Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: kunit-dev@googlegroups.com
Cc: linux-kselftest@vger.kernel.org
Cc: Bodo Stroesser <bostroesser@gmail.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Yanko Kaneti <yaneti@declera.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 include/kunit/test.h |  4 ++++
 lib/kunit/test.c     | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 24b40e5c160b..a6eef96a409c 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -215,6 +215,8 @@ static inline char *kunit_status_to_ok_not_ok(enum kunit_status status)
  * struct kunit_suite - describes a related collection of &struct kunit_case
  *
  * @name:	the name of the test. Purely informational.
+ * @init_suite:	called once per test suite before the test cases.
+ * @exit_suite:	called once per test suite after all test cases.
  * @init:	called before every test case.
  * @exit:	called after every test case.
  * @test_cases:	a null terminated array of test cases.
@@ -229,6 +231,8 @@ static inline char *kunit_status_to_ok_not_ok(enum kunit_status status)
  */
 struct kunit_suite {
 	const char name[256];
+	int (*init_suite)(void);
+	void (*exit_suite)(void);
 	int (*init)(struct kunit *test);
 	void (*exit)(struct kunit *test);
 	struct kunit_case *test_cases;
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index d79ecb86ea57..c271692ced93 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -397,9 +397,19 @@ int kunit_run_tests(struct kunit_suite *suite)
 {
 	char param_desc[KUNIT_PARAM_DESC_SIZE];
 	struct kunit_case *test_case;
+	int res = 0;
 
 	kunit_print_subtest_start(suite);
 
+	if (suite->init_suite)
+		res = suite->init_suite();
+
+	if (res < 0) {
+		kunit_log(KERN_INFO, suite, KUNIT_SUBTEST_INDENT
+			  "# Suite initialization failed (%d)\n", res);
+		goto end;
+	}
+
 	kunit_suite_for_each_test_case(suite, test_case) {
 		struct kunit test = { .param_value = NULL, .param_index = 0 };
 		test_case->status = KUNIT_SKIPPED;
@@ -439,6 +449,10 @@ int kunit_run_tests(struct kunit_suite *suite)
 				      test.status_comment);
 	}
 
+	if (suite->exit_suite)
+		suite->exit_suite();
+
+end:
 	kunit_print_subtest_end(suite);
 
 	return 0;

[PATCH v3 3/3] configfs: Add unit tests

[Bart Van Assche]

Testing configfs read and write behavior is non-trivial and tedious.
Hence these configfs kunit tests that make it easier to test configfs
text and binary attribute support. This is how I run these tests:

set -e
if [ -e .config ]; then
    make ARCH=um mrproper
fi
if [ ! -e .kunit/.kunitconfig ]; then
    cat <<EOF >.kunit/.kunitconfig
CONFIG_CONFIGFS_FS=y
CONFIG_CONFIGFS_KUNIT_TEST=y
CONFIG_KUNIT=y
CONFIG_PROVE_LOCKING=y
CONFIG_SYSFS=y
CONFIG_UBSAN=y
EOF
    cp .kunit/.kunitconfig .kunit/.config
fi
./tools/testing/kunit/kunit.py run

Cc: Bodo Stroesser <bostroesser@gmail.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Yanko Kaneti <yaneti@declera.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 fs/configfs/Kconfig         |   8 +
 fs/configfs/Makefile        |   2 +
 fs/configfs/configfs-test.c | 427 ++++++++++++++++++++++++++++++++++++
 3 files changed, 437 insertions(+)
 create mode 100644 fs/configfs/configfs-test.c

diff --git a/fs/configfs/Kconfig b/fs/configfs/Kconfig
index 272b64456999..9f8f3d8ca67d 100644
--- a/fs/configfs/Kconfig
+++ b/fs/configfs/Kconfig
@@ -10,3 +10,11 @@ config CONFIGFS_FS
 
 	  Both sysfs and configfs can and should exist together on the
 	  same system. One is not a replacement for the other.
+
+config CONFIGFS_KUNIT_TEST
+	tristate "Configfs Kunit test" if !KUNIT_ALL_TESTS
+	depends on CONFIGFS_FS && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Run the configfs unit tests at boot time. For more information, see
+	  also the Kunit documentation in Documentation/dev-tools/kunit/.
diff --git a/fs/configfs/Makefile b/fs/configfs/Makefile
index 0200498ede27..388003fa9f37 100644
--- a/fs/configfs/Makefile
+++ b/fs/configfs/Makefile
@@ -6,3 +6,5 @@
 obj-$(CONFIG_CONFIGFS_FS)	+= configfs.o
 
 configfs-objs	:= inode.o file.o dir.o symlink.o mount.o item.o
+
+obj-$(CONFIG_CONFIGFS_KUNIT_TEST) += configfs-test.o
diff --git a/fs/configfs/configfs-test.c b/fs/configfs/configfs-test.c
new file mode 100644
index 000000000000..03044c5fc9b6
--- /dev/null
+++ b/fs/configfs/configfs-test.c
@@ -0,0 +1,427 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <kunit/test.h>
+#include <linux/configfs.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/uio.h>
+
+/*
+ * Maximum number of bytes supported by the configfs attributes in this unit
+ * test.
+ */
+enum { ATTR_MAX_SIZE = 256 };
+
+static struct test_item {
+	uint32_t nbytes;
+	char data[ATTR_MAX_SIZE];
+} bin_attr, text_attr;
+
+static ssize_t attr_read(struct test_item *ti, void *buf, size_t len)
+{
+	size_t nbytes = min_t(size_t, len, ti->nbytes);
+
+	memcpy(buf, ti->data, nbytes);
+	return nbytes;
+}
+
+static ssize_t attr_write(struct test_item *ti, const void *buf, size_t len)
+{
+	if (len > ATTR_MAX_SIZE)
+		return -EINVAL;
+	ti->nbytes = len;
+	memcpy(ti->data, buf, len);
+	return len;
+}
+
+static DEFINE_SEMAPHORE(bin_attr_written);
+
+static ssize_t bin_attr_read(struct config_item *item, void *buf, size_t len)
+{
+	return buf ? attr_read(&bin_attr, buf, len) : bin_attr.nbytes;
+}
+
+static ssize_t bin_attr_write(struct config_item *item, const void *buf,
+			      size_t len)
+{
+	up(&bin_attr_written);
+	return attr_write(&bin_attr, buf, len);
+}
+
+CONFIGFS_BIN_ATTR(, bin_attr, NULL, ATTR_MAX_SIZE);
+
+static struct configfs_bin_attribute *bin_attrs[] = {
+	&attr_bin_attr,
+	NULL,
+};
+
+static ssize_t text_attr_show(struct config_item *item, char *buf)
+{
+	return attr_read(&text_attr, buf, strlen(buf));
+}
+
+static ssize_t text_attr_store(struct config_item *item, const char *buf,
+			       size_t size)
+{
+	return attr_write(&text_attr, buf, size);
+}
+
+CONFIGFS_ATTR(, text_attr);
+
+static struct configfs_attribute *text_attrs[] = {
+	&attr_text_attr,
+	NULL,
+};
+
+static const struct config_item_type test_configfs_type = {
+	.ct_owner	= THIS_MODULE,
+	.ct_bin_attrs	= bin_attrs,
+	.ct_attrs	= text_attrs,
+};
+
+/*
+ * Return the file mode if @path exists or an error code if opening @path via
+ * filp_open() in read-only mode failed.
+ */
+int get_file_mode(const char *path)
+{
+	struct file *file;
+	int res;
+
+	file = filp_open(path, O_RDONLY, 0400);
+	if (IS_ERR(file)) {
+		res = PTR_ERR(file);
+		goto out;
+	}
+	res = file_inode(file)->i_mode;
+	filp_close(file, NULL);
+
+out:
+	return res;
+}
+
+static int mkdir(const char *name, umode_t mode)
+{
+	struct dentry *dentry;
+	struct path path;
+	int err;
+
+	err = get_file_mode(name);
+	if (err >= 0 && S_ISDIR(err))
+		return 0;
+
+	dentry = kern_path_create(AT_FDCWD, name, &path, LOOKUP_DIRECTORY);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+
+	err = vfs_mkdir(&init_user_ns, d_inode(path.dentry), dentry, mode);
+	done_path_create(&path, dentry);
+
+	return err;
+}
+
+static int mount_configfs(void)
+{
+	int res;
+
+	res = get_file_mode("/sys/kernel/config/unit-test");
+	if (res >= 0)
+		return 0;
+	res = mkdir("/sys", 0755);
+	if (res < 0)
+		return res;
+	res = mkdir("/sys/kernel", 0755);
+	if (res < 0)
+		return res;
+	res = mkdir("/sys/kernel/config", 0755);
+	if (res < 0)
+		return res;
+	pr_info("mounting configfs ...\n");
+	res = do_mount("", "/sys/kernel/config", "configfs", 0, NULL);
+	if (res < 0)
+		pr_err("mounting configfs failed: %d\n", res);
+	else
+		pr_info("mounted configfs.\n");
+	return res;
+}
+
+static void unmount_configfs(void)
+{
+	/* How to unmount a filesystem from kernel code? */
+}
+
+#define KUNIT_EXPECT_MODE(test, left_arg, mask, right)			\
+({									\
+	const int left = (left_arg);					\
+									\
+	KUNIT_EXPECT_TRUE_MSG(test, left >= 0 && (left & mask) == right, \
+		"(" #left_arg "(%d) & " #mask ") != " #right, left);	\
+})
+
+static void configfs_mounted(struct kunit *test)
+{
+	KUNIT_EXPECT_MODE(test, get_file_mode("/"), 0500, 0500);
+	KUNIT_EXPECT_MODE(test, get_file_mode("/sys"), 0500, 0500);
+	KUNIT_EXPECT_MODE(test, get_file_mode("/sys/kernel"), 0500, 0500);
+	KUNIT_EXPECT_MODE(test, get_file_mode("/sys/kernel/config"), 0500, 0500);
+	KUNIT_EXPECT_MODE(test, get_file_mode("/sys/kernel/config/unit-test"),
+			  0500, 0500);
+	KUNIT_EXPECT_MODE(test, get_file_mode
+			  ("/sys/kernel/config/unit-test/text_attr"),
+			  0700, 0600);
+}
+
+static void configfs_text_attr(struct kunit *test)
+{
+	struct file *f = filp_open("/sys/kernel/config/unit-test/text_attr",
+				   O_RDWR, 0);
+	static const char text1[] =
+		"The quick brown fox jumps over the lazy dog";
+	const int off1 = 0;
+	const int len1 = strlen(text1);
+	static const char text2[] = "huge";
+	const int off2 = strlen(text1) - strlen(text2) - 4;
+	const int len2 = strlen(text2);
+	char text3[sizeof(text1)];
+	int res;
+	loff_t pos;
+
+	KUNIT_EXPECT_EQ(test, PTR_ERR_OR_ZERO(f), 0);
+	if (IS_ERR(f))
+		return;
+	/* Write at a non-zero offset. */
+	pos = off2;
+	res = kernel_write(f, text2, len2, &pos);
+	KUNIT_EXPECT_EQ(test, res, len2);
+	KUNIT_EXPECT_EQ(test, pos, off2 + len2);
+	/* Verify the effect of the above kernel_write() call. */
+	pos = 0;
+	res = kernel_read(f, text3, sizeof(text3), &pos);
+	KUNIT_EXPECT_EQ(test, res, len2);
+	KUNIT_EXPECT_EQ(test, pos, len2);
+	if (res >= 0) {
+		text3[res] = '\0';
+		KUNIT_EXPECT_STREQ(test, text3, text2);
+	}
+	/* Write at offset zero. */
+	pos = off1;
+	res = kernel_write(f, text1, len1, &pos);
+	KUNIT_EXPECT_EQ(test, res, len1);
+	KUNIT_EXPECT_EQ(test, pos, len1);
+	/* Verify the effect of the above kernel_write() call. */
+	pos = 0;
+	res = kernel_read(f, text3, sizeof(text3), &pos);
+	KUNIT_EXPECT_EQ(test, res, len1);
+	KUNIT_EXPECT_EQ(test, pos, len1);
+	if (res >= 0) {
+		text3[res] = '\0';
+		KUNIT_EXPECT_STREQ(test, text3, text1);
+	}
+	/* Write at a non-zero offset. */
+	pos = off2;
+	res = kernel_write(f, text2, len2, &pos);
+	KUNIT_EXPECT_EQ(test, res, len2);
+	KUNIT_EXPECT_EQ(test, pos, off2 + len2);
+	/* Verify that the above kernel_write() call truncated the attribute. */
+	pos = 0;
+	res = kernel_read(f, text3, sizeof(text3), &pos);
+	KUNIT_EXPECT_EQ(test, res, len2);
+	KUNIT_EXPECT_EQ(test, pos, len2);
+	if (res >= 0) {
+		text3[res] = '\0';
+		KUNIT_EXPECT_STREQ(test, text3, text2);
+	}
+	/* Read from offset 1. */
+	pos = 1;
+	res = kernel_read(f, text3, sizeof(text3), &pos);
+	KUNIT_EXPECT_EQ(test, res, len2 - 1);
+	KUNIT_EXPECT_EQ(test, pos, len2);
+	if (res >= 0) {
+		text3[res] = '\0';
+		KUNIT_EXPECT_STREQ(test, text3, text2 + 1);
+	}
+	/* Write at offset -1. */
+	pos = -1;
+	res = kernel_write(f, text1, len1, &pos);
+	KUNIT_EXPECT_EQ(test, res, -EINVAL);
+	/* Write at the largest possible positive offset. */
+	pos = LLONG_MAX - len1;
+	res = kernel_write(f, text1, len1, &pos);
+	KUNIT_EXPECT_EQ(test, res, len1);
+	/* Read from offset -1. */
+	pos = -1;
+	res = kernel_read(f, text3, sizeof(text3), &pos);
+	KUNIT_EXPECT_EQ(test, res, -EINVAL);
+	/* Read from the largest possible positive offset. */
+	pos = LLONG_MAX - sizeof(text3);
+	res = kernel_read(f, text3, sizeof(text3), &pos);
+	KUNIT_EXPECT_EQ(test, res, 0);
+	/* Verify the effect of the latest kernel_write() call. */
+	pos = 0;
+	res = kernel_read(f, text3, sizeof(text3), &pos);
+	KUNIT_EXPECT_EQ(test, res, len1);
+	KUNIT_EXPECT_EQ(test, pos, len1);
+	if (res >= 0) {
+		text3[res] = '\0';
+		KUNIT_EXPECT_STREQ(test, text3, text1);
+	}
+	filp_close(f, NULL);
+}
+
+#define KUNIT_EXPECT_MEMEQ(test, left, right, len)			\
+	KUNIT_EXPECT_TRUE_MSG(test, memcmp(left, right, len) == 0,	\
+			      #left " != " #right ": %.*s <> %.*s",	\
+			      (int)len, left, (int)len, right)
+
+static void configfs_bin_attr(struct kunit *test)
+{
+	struct file *f = filp_open("/sys/kernel/config/unit-test/bin_attr",
+				   O_RDWR, 0);
+	static const u8 data1[] =
+		"\xff\x00The quick brown fox jumps over the lazy dog";
+	const int off1 = 0;
+	const int len1 = sizeof(data1) - 1;
+	static const u8 data2[] = "huge";
+	const int off2 = len1 - strlen(data2) - 4;
+	const int len2 = strlen(data2);
+	u8 data3[sizeof(data1)];
+	int res;
+	loff_t pos;
+
+	bin_attr.nbytes = len1;
+
+	KUNIT_EXPECT_EQ(test, PTR_ERR_OR_ZERO(f), 0);
+	if (IS_ERR(f))
+		return;
+	/* Write at offset zero. */
+	pos = off1;
+	res = kernel_write(f, data1, len1, &pos);
+	KUNIT_EXPECT_EQ(test, res, len1);
+	KUNIT_EXPECT_EQ(test, pos, off1 + len1);
+	/* Write at a non-zero offset. */
+	pos = off2;
+	res = kernel_write(f, data2, len2, &pos);
+	KUNIT_EXPECT_EQ(test, res, len2);
+	KUNIT_EXPECT_EQ(test, pos, off2 + len2);
+	filp_close(f, NULL);
+
+	/*
+	 * buffer->bin_attr->write() is called from inside
+	 * configfs_release_bin_file() and the latter function is
+	 * called asynchronously. Hence the down() calls below to wait
+	 * until the write method has been called.
+	 */
+	down(&bin_attr_written);
+	down(&bin_attr_written);
+
+	f = filp_open("/sys/kernel/config/unit-test/bin_attr", O_RDONLY, 0);
+	KUNIT_EXPECT_EQ(test, PTR_ERR_OR_ZERO(f), 0);
+	if (IS_ERR(f))
+		return;
+	/* Verify the effect of the two kernel_write() calls. */
+	pos = 0;
+	res = kernel_read(f, data3, sizeof(data3), &pos);
+	KUNIT_EXPECT_EQ(test, res, len1);
+	KUNIT_EXPECT_EQ(test, pos, len1);
+	if (res >= 0) {
+		data3[res] = '\0';
+		KUNIT_EXPECT_MEMEQ(test, data3,
+			"\xff\x00The quick brown fox jumps over the huge dog",
+			len1);
+	}
+	/* Read from offset 1. */
+	pos = 1;
+	res = kernel_read(f, data3, sizeof(data3), &pos);
+	KUNIT_EXPECT_EQ(test, res, len1 - 1);
+	KUNIT_EXPECT_EQ(test, pos, len1);
+	if (res >= 0) {
+		data3[res] = '\0';
+		KUNIT_EXPECT_MEMEQ(test, data3,
+			"\x00The quick brown fox jumps over the huge dog",
+			len1 - 1);
+	}
+	filp_close(f, NULL);
+
+	f = filp_open("/sys/kernel/config/unit-test/bin_attr", O_RDWR, 0);
+	KUNIT_EXPECT_EQ(test, PTR_ERR_OR_ZERO(f), 0);
+	if (IS_ERR(f))
+		return;
+	/* Write at offset -1. */
+	pos = -1;
+	res = kernel_write(f, data1, len1, &pos);
+	KUNIT_EXPECT_EQ(test, res, -EINVAL);
+	/* Write at the largest possible positive offset. */
+	pos = LLONG_MAX - len1;
+	res = kernel_write(f, data1, len1, &pos);
+	KUNIT_EXPECT_EQ(test, res, -EFBIG);
+	filp_close(f, NULL);
+
+	/* Wait until the .write() function has been called. */
+	down(&bin_attr_written);
+
+	KUNIT_EXPECT_EQ(test, bin_attr.nbytes, 0);
+
+	f = filp_open("/sys/kernel/config/unit-test/bin_attr", O_RDONLY, 0);
+	KUNIT_EXPECT_EQ(test, PTR_ERR_OR_ZERO(f), 0);
+	if (IS_ERR(f))
+		return;
+	/* Read from offset -1. */
+	pos = -1;
+	res = kernel_read(f, data3, sizeof(data3), &pos);
+	KUNIT_EXPECT_EQ(test, res, -EINVAL);
+	/* Read from the largest possible positive offset. */
+	pos = LLONG_MAX - sizeof(data3);
+	res = kernel_read(f, data3, sizeof(data3), &pos);
+	KUNIT_EXPECT_EQ(test, res, 0);
+	KUNIT_EXPECT_EQ(test, pos, LLONG_MAX - sizeof(data3));
+	/* Read from offset zero. */
+	pos = 0;
+	res = kernel_read(f, data3, sizeof(data3), &pos);
+	KUNIT_EXPECT_EQ(test, res, 0);
+	KUNIT_EXPECT_EQ(test, pos, 0);
+	filp_close(f, NULL);
+}
+
+static struct kunit_case configfs_test_cases[] = {
+	KUNIT_CASE(configfs_mounted),
+	KUNIT_CASE(configfs_text_attr),
+	KUNIT_CASE(configfs_bin_attr),
+	{},
+};
+
+static struct configfs_subsystem test_subsys = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf = "unit-test",
+			.ci_type    = &test_configfs_type,
+		}
+	},
+};
+
+static int configfs_suite_init(void)
+{
+	int res;
+
+	config_group_init(&test_subsys.su_group);
+	mutex_init(&test_subsys.su_mutex);
+	res = configfs_register_subsystem(&test_subsys);
+	if (res < 0) {
+		pr_err("Registration of configfs subsystem failed: %d\n", res);
+		return res;
+	}
+	return mount_configfs();
+}
+
+static void configfs_suite_exit(void)
+{
+	configfs_unregister_subsystem(&test_subsys);
+	unmount_configfs();
+}
+
+static struct kunit_suite configfs_test_module = {
+	.name		= "configfs unit tests",
+	.init_suite	= configfs_suite_init,
+	.exit_suite	= configfs_suite_exit,
+	.test_cases	= configfs_test_cases,
+};
+kunit_test_suites(&configfs_test_module);

Re: [PATCH v3 3/3] configfs: Add unit tests

[kernel test robot]

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Hi Bart,

I love your patch! Yet something to improve:

[auto build test ERROR on hch-configfs/for-next]
[also build test ERROR on linus/master v5.14-rc3 next-20210729]
[cannot apply to linux/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Bart-Van-Assche/Restore-the-kernel-v5-13-text-attribute-write-behavior/20210730-113708
base:   git://git.infradead.org/users/hch/configfs.git for-next
config: microblaze-randconfig-r036-20210730 (attached as .config)
compiler: microblaze-linux-gcc (GCC) 10.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/808490b67fe8580bcfca28bc36abb79d6ec13bd4
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Bart-Van-Assche/Restore-the-kernel-v5-13-text-attribute-write-behavior/20210730-113708
        git checkout 808490b67fe8580bcfca28bc36abb79d6ec13bd4
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=microblaze 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>, old ones prefixed by <<):

ERROR: modpost: missing MODULE_LICENSE() in fs/configfs/configfs-test.o
>> ERROR: modpost: "do_mount" [fs/configfs/configfs-test.ko] undefined!

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

[-- Attachment #2: config.gz --]
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Re: [PATCH v3 0/3] Restore the kernel v5.13 text attribute write behavior

[Bart Van Assche]

On 7/29/21 8:35 PM, Bart Van Assche wrote:
> This patch series restores the v5.13 text attribute write behavior and also
> adds unit tests for configfs. Please consider these patches for inclusion in
> the Linux kernel.

(replying to my own email)

The build bot reported the following for this patch series:

All errors (new ones prefixed by >>, old ones prefixed by <<):

ERROR: modpost: missing MODULE_LICENSE() in fs/configfs/configfs-test.o
 >> ERROR: modpost: "do_mount" [fs/configfs/configfs-test.ko] undefined!

I will fix these issues and repost this patch series.

Bart.