tests/migration: mem leak fix

‘data’ has the possibility of memory leaks， so use the
glib macros g_autofree recommended by CODING_STYLE.rst
to automatically release the memory that returned from
g_malloc().

Signed-off-by: Mao Zhongyi <maozhongyi@cmss.chinamobile.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20200603080904.997083-2-maozhongyi@cmss.chinamobile.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

tests/migration/stress.c

@@ -170,26 +170,14 @@ static unsigned long long now(void)
 static int stressone(unsigned long long ramsizeMB)
 {
     size_t pagesPerMB = 1024 * 1024 / PAGE_SIZE;
-    char *ram = malloc(ramsizeMB * 1024 * 1024);
+    g_autofree char *ram = g_malloc(ramsizeMB * 1024 * 1024);
     char *ramptr;
     size_t i, j, k;
-    char *data = malloc(PAGE_SIZE);
+    g_autofree char *data = g_malloc(PAGE_SIZE);
     char *dataptr;
     size_t nMB = 0;
     unsigned long long before, after;
 
-    if (!ram) {
-        fprintf(stderr, "%s (%05d): ERROR: cannot allocate %llu MB of RAM: %s\n",
-                argv0, gettid(), ramsizeMB, strerror(errno));
-        return -1;
-    }
-    if (!data) {
-        fprintf(stderr, "%s (%d): ERROR: cannot allocate %d bytes of RAM: %s\n",
-                argv0, gettid(), PAGE_SIZE, strerror(errno));
-        free(ram);
-        return -1;
-    }
-
     /* We don't care about initial state, but we do want
      * to fault it all into RAM, otherwise the first iter
      * of the loop below will be quite slow. We can't use
@@ -198,8 +186,6 @@ static int stressone(unsigned long long ramsizeMB)
     memset(ram, 0xfe, ramsizeMB * 1024 * 1024);
 
     if (random_bytes(data, PAGE_SIZE) < 0) {
-        free(ram);
-        free(data);
         return -1;
     }
 
@@ -227,9 +213,6 @@ static int stressone(unsigned long long ramsizeMB)
             }
         }
     }
-
-    free(data);
-    free(ram);
 }