TESTS: add a flag --usb so we can clamp all i/o to at most 120k

Add checks for maximum tranfer length to all commands that are limited
by BlockLimits/MTL

test-tool/test_writesame16_wrprotect.c

@@ -18,6 +18,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <alloca.h>
 
 #include <CUnit/CUnit.h>
 
@@ -29,7 +30,7 @@ void
 test_writesame16_wrprotect(void)
 {
 	int i, ret;
-	unsigned char *buf;
+	unsigned char *buf = alloca(block_size);
 
 	CHECK_FOR_DATALOSS;
 	CHECK_FOR_SBC;
@@ -40,12 +41,16 @@ test_writesame16_wrprotect(void)
 	 */
 	logging(LOG_VERBOSE, LOG_BLANK_LINE);
 	logging(LOG_VERBOSE, "Test WRITESAME16 with non-zero WRPROTECT");
-	buf = malloc(block_size);
+
 	for (i = 1; i < 8; i++) {
 		ret = writesame16_invalidfieldincdb(iscsic, tgt_lun, 0,
 						    block_size, 1,
 						    0, 0, i, 0, buf);
+		if (ret == -2) {
+			logging(LOG_NORMAL, "[SKIPPED] WRITESAME16 is not implemented.");
+			CU_PASS("[SKIPPED] Target does not support WRITESAME16. Skipping test");
+			return;
+		}
 		CU_ASSERT_EQUAL(ret, 0);
 	}
-	free(buf);
 }