From 5d419c790e648c7a2f96f34ed1b93b326f725545 Mon Sep 17 00:00:00 2001
From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Date: Sat, 13 Aug 2022 17:17:05 +0200
Subject: [PATCH] Makefile: fix build with kernel < 5.6

Fix the following build failure with kernel >= 5.1 and < 5.5 (i.e.
before
https://github.com/torvalds/linux/commit/9e3aa61ae3e01ce1ce6361a41ef725e1f4d1d2bf)
raised since version 0.11.21 and
https://github.com/ColinIanKing/stress-ng/commit/3d6fccdbe53d0cbcb75dd4b91571aaaae7ee1ad4:

In file included from stress-io-uring.c:26:
io-uring.h:1:9: error: macro names must be identifiers
    1 | #define #define HAVE_IORING_OP_NOP 0
      |         ^

Moreover, IORING_OP_FALLOCATE is not available before kernel 5.6 and
https://github.com/torvalds/linux/commit/d63d1b5edb7b832210bfde587ba9e7549fa064eb

Fixes:
 - http://autobuild.buildroot.org/results/1bf3f2bbc849bdce531d56b1024fa87f0c1ae667

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[Retrieved (and backported) from
https://github.com/ColinIanKing/stress-ng/commit/5d419c790e648c7a2f96f34ed1b93b326f725545]
---
 Makefile          | 2 +-
 stress-io-uring.c | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 2f9cc9918..ee17ae08b 100644
--- a/Makefile
+++ b/Makefile
@@ -528,7 +528,7 @@ stress-personality.c: personality.h
 #
 io-uring.h:
 	$(V)$(CPP) $(CFLAGS) core-io-uring.c  | $(GREP) IORING_OP | sed 's/,//' | \
-	sed 's/IORING_OP_/#define HAVE_IORING_OP_/' > io-uring.h
+	sed 's/.*\(IORING_OP_.*\)/#define HAVE_\1/' > io-uring.h
 	$(Q)echo "MK io-uring.h"
 
 stress-io-uring.c: io-uring.h
diff --git a/stress-io-uring.c b/stress-io-uring.c
index ab9fd0749..84f463611 100644
--- a/stress-io-uring.c
+++ b/stress-io-uring.c
@@ -311,7 +311,11 @@ static inline int stress_io_uring_complete(
 			break;
 
 		cqe = &cring->cqes[head & *submit->cq_ring.ring_mask];
-		if ((cqe->res < 0) && (opcode != IORING_OP_FALLOCATE)) {
+		if ((cqe->res < 0)
+#ifdef HAVE_IORING_OP_FALLOCATE
+			&& (opcode != IORING_OP_FALLOCATE)
+#endif
+		) {
 			const int err = abs(cqe->res);
 
 			/* Silently ignore EOPNOTSUPP completion errors */