mremap: Fix to work correctly when old_page is large_page

Change-Id: I5a589383644a8098d910e49cd7ade6df325e0366
Refs: #1383

test/issues/1383/C1383T01.c

@@ -0,0 +1,93 @@
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define PAGES 3
+#define MAP_HUGE_SHIFT 26
+
+static unsigned long ps, hps;
+
+void *hugetlb_mmap(unsigned long size, int pgshift)
+{
+	return mmap(NULL, size, PROT_WRITE | PROT_READ,
+			MAP_ANONYMOUS | MAP_PRIVATE |
+			MAP_HUGETLB | (pgshift << MAP_HUGE_SHIFT),
+			-1, 0);
+}
+
+int main(int argc, char **argv)
+{
+	void *p1, *p2, *p3, *p4, *old_addr, *new_addr;
+	int i, pgshift, err, ret = 0;
+	unsigned long base_start, base_size, new_start, new_size;
+	size_t size, remap_size;
+
+	if (argc < 2) {
+		printf("error: too few arguments\n");
+		ret = -1;
+		goto out;
+	}
+	pgshift = atoi(argv[1]);
+	hps = (1 << pgshift);
+	ps = getpagesize();
+	size = hps * PAGES;
+
+	for (i = 0; i < 4; i++) {
+		p1 = hugetlb_mmap(size, pgshift);
+		if (p1 == MAP_FAILED) {
+			perror("mmap fail: ");
+			ret = -1;
+			goto out;
+		}
+		printf("** mmap p1: %p - %p\n", p1, p1 + size);
+
+		p2 = hugetlb_mmap(size, pgshift);
+		if (p2 == MAP_FAILED) {
+			perror("mmap fail: ");
+			ret = -1;
+			goto out;
+		}
+		printf("** mmap p2: %p - %p\n", p2, p2 + size);
+
+		p3 = hugetlb_mmap(size, pgshift);
+		if (p3 == MAP_FAILED) {
+			perror("mmap fail: ");
+			ret = -1;
+			goto out;
+		}
+		printf("** mmap p3: %p - %p\n", p3, p3 + size);
+
+		/* make page populate */
+		memset(p1, 0xff, size);
+		memset(p2, 0xff, size);
+		memset(p3, 0x77, size);
+
+		remap_size = size - ps;
+		old_addr = p1 + ps * (i >> 1);
+		new_addr = p3 + ps * (i & 1);
+
+		p4 = mremap(old_addr, remap_size, remap_size,
+				MREMAP_FIXED | MREMAP_MAYMOVE, new_addr);
+		if (p4 == MAP_FAILED) {
+			perror("mremap fail: ");
+			ret = -1;
+			goto out;
+		}
+		if (memcmp(p4, p2, remap_size)) {
+			printf("memcmp detect DIFF!!\n");
+			ret = -1;
+			goto out;
+		}
+		printf("*** mremap p4: %p - %p\n", p4, p4 + remap_size);
+
+	}
+
+	printf("[OK] mremap on HUGETLB\n");
+out:
+	return ret;
+}