Merge branch 'akpm' (patches from Andrew)

Merge fourth patch-bomb from Andrew Morton:

 - sys_membarier syscall

 - seq_file interface changes

 - a few misc fixups

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  revert "ocfs2/dlm: use list_for_each_entry instead of list_for_each"
  mm/early_ioremap: add explicit #include of asm/early_ioremap.h
  fs/seq_file: convert int seq_vprint/seq_printf/etc... returns to void
  selftests: enhance membarrier syscall test
  selftests: add membarrier syscall test
  sys_membarrier(): system-wide memory barrier (generic, x86)
  MODSIGN: fix a compilation warning in extract-cert

tools/testing/selftests/membarrier/Makefile

+CFLAGS += -g -I../../../../usr/include/
+
+all:
+	$(CC) $(CFLAGS) membarrier_test.c -o membarrier_test
+
+TEST_PROGS := membarrier_test
+
+include ../lib.mk
+
+clean:
+	$(RM) membarrier_test

tools/testing/selftests/membarrier/membarrier_test.c

+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__
+
+#include <linux/membarrier.h>
+#include <asm-generic/unistd.h>
+#include <sys/syscall.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+#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 enum test_membarrier_status test_membarrier_cmd_fail(void)
+{
+	int cmd = -1, flags = 0;
+
+	if (sys_membarrier(cmd, flags) != -1) {
+		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 enum test_membarrier_status test_membarrier_success(void)
+{
+	int cmd = MEMBARRIER_CMD_SHARED, flags = 0;
+
+	if (sys_membarrier(cmd, flags) != 0) {
+		printf("membarrier: Executing MEMBARRIER_CMD_SHARED failed. %s.\n",
+				strerror(errno));
+		return TEST_MEMBARRIER_FAIL;
+	}
+
+	printf("membarrier: MEMBARRIER_CMD_SHARED success.\n");
+	return TEST_MEMBARRIER_PASS;
+}
+
+static enum test_membarrier_status test_membarrier(void)
+{
+	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 enum test_membarrier_status test_membarrier_query(void)
+{
+	int flags = 0, ret;
+
+	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)
+{
+	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();
+}