selftests: enhance membarrier syscall test

Update the membarrier syscall self-test to match the membarrier
interface.  Extend coverage of the interface.  Consider ENOSYS as a
"SKIP" test, since it is a valid configuration, but does not allow
testing the system call.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Pranith Kumar <bobby.prani@gmail.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 75 insertions, 25 deletions

diff --git a/tools/testing/selftests/membarrier/membarrier_test.c b/tools/testing/selftests/membarrier/membarrier_test.c
index 3c9f2179acd8..dde312508007 100644
--- a/tools/testing/selftests/membarrier/membarrier_test.c
+++ b/tools/testing/selftests/membarrier/membarrier_test.c
@@ -10,62 +10,112 @@
 
 #include "../kselftest.h"
 
+enum test_membarrier_status {
+        TEST_MEMBARRIER_PASS = 0,
+        TEST_MEMBARRIER_FAIL,
+        TEST_MEMBARRIER_SKIP,
+};
+
 static int sys_membarrier(int cmd, int flags)
 {
         return syscall(__NR_membarrier, cmd, flags);
 }
 
-static void test_membarrier_fail(void)
+static enum test_membarrier_status test_membarrier_cmd_fail(void)
 {
         int cmd = -1, flags = 0;
 
         if (sys_membarrier(cmd, flags) != -1) {
-                printf("membarrier: Should fail but passed\n");
-                ksft_exit_fail();
+                printf("membarrier: Wrong command should fail but passed.\n");
+                return TEST_MEMBARRIER_FAIL;
+        }
+        return TEST_MEMBARRIER_PASS;
+}
+
+static enum test_membarrier_status test_membarrier_flags_fail(void)
+{
+        int cmd = MEMBARRIER_CMD_QUERY, flags = 1;
+
+        if (sys_membarrier(cmd, flags) != -1) {
+                printf("membarrier: Wrong flags should fail but passed.\n");
+                return TEST_MEMBARRIER_FAIL;
         }
+        return TEST_MEMBARRIER_PASS;
 }
 
-static void test_membarrier_success(void)
+static enum test_membarrier_status test_membarrier_success(void)
 {
-        int flags = 0;
+        int cmd = MEMBARRIER_CMD_SHARED, flags = 0;
 
-        if (sys_membarrier(MEMBARRIER_CMD_SHARED, flags) != 0) {
-                printf("membarrier: Executing MEMBARRIER failed, %s\n",
+        if (sys_membarrier(cmd, flags) != 0) {
+                printf("membarrier: Executing MEMBARRIER_CMD_SHARED failed. %s.\n",
                                 strerror(errno));
-                ksft_exit_fail();
+                return TEST_MEMBARRIER_FAIL;
         }
 
-        printf("membarrier: MEMBARRIER_CMD_SHARED success\n");
+        printf("membarrier: MEMBARRIER_CMD_SHARED success.\n");
+        return TEST_MEMBARRIER_PASS;
 }
 
-static void test_membarrier(void)
+static enum test_membarrier_status test_membarrier(void)
 {
-        test_membarrier_fail();
-        test_membarrier_success();
+        enum test_membarrier_status status;
+
+        status = test_membarrier_cmd_fail();
+        if (status)
+                return status;
+        status = test_membarrier_flags_fail();
+        if (status)
+                return status;
+        status = test_membarrier_success();
+        if (status)
+                return status;
+        return TEST_MEMBARRIER_PASS;
 }
 
-static int test_membarrier_exists(void)
+static enum test_membarrier_status test_membarrier_query(void)
 {
-        int flags = 0;
-
-        if (sys_membarrier(MEMBARRIER_CMD_QUERY, flags))
-                return 0;
+        int flags = 0, ret;
 
-        return 1;
+        printf("membarrier MEMBARRIER_CMD_QUERY ");
+        ret = sys_membarrier(MEMBARRIER_CMD_QUERY, flags);
+        if (ret < 0) {
+                printf("failed. %s.\n", strerror(errno));
+                switch (errno) {
+                case ENOSYS:
+                        /*
+                         * It is valid to build a kernel with
+                         * CONFIG_MEMBARRIER=n. However, this skips the tests.
+                         */
+                        return TEST_MEMBARRIER_SKIP;
+                case EINVAL:
+                default:
+                        return TEST_MEMBARRIER_FAIL;
+                }
+        }
+        if (!(ret & MEMBARRIER_CMD_SHARED)) {
+                printf("command MEMBARRIER_CMD_SHARED is not supported.\n");
+                return TEST_MEMBARRIER_FAIL;
+        }
+        printf("syscall available.\n");
+        return TEST_MEMBARRIER_PASS;
 }
 
 int main(int argc, char **argv)
 {
-        printf("membarrier: MEMBARRIER_CMD_QUERY ");
-        if (test_membarrier_exists()) {
-                printf("syscall implemented\n");
-                test_membarrier();
-        } else {
-                printf("syscall not implemented!\n");
+        switch (test_membarrier_query()) {
+        case TEST_MEMBARRIER_FAIL:
                 return ksft_exit_fail();
+        case TEST_MEMBARRIER_SKIP:
+                return ksft_exit_skip();
+        }
+        switch (test_membarrier()) {
+        case TEST_MEMBARRIER_FAIL:
+                return ksft_exit_fail();
+        case TEST_MEMBARRIER_SKIP:
+                return ksft_exit_skip();
         }
 
         printf("membarrier: tests done!\n");
-
         return ksft_exit_pass();
 }