src/Makefile: improve header check for miniublk

After make / make install, src/nvme-passthru-admin-uring is not built
when linux/ublk_cmd.h is missing from userspace kernel headers, even if
liburing is new enough (IORING_OP_URING_CMD). Tests such as nvme/067
then fail with sudo: src/nvme-passthru-admin-uring: command not found.
nvme-passthru-admin-uring does not include linux/ublk_cmd.h; only
miniublk needs it. The Makefile currently ties all C_URING_TARGETS to
the same HAVE_LIBURING + HAVE_UBLK_HEADER gate (or equivalent), so the
NVMe helper is skipped together with miniublk.

When ublk stack is not available, still build metadata and
nvme-passthru-admin-uring if HAVE_LIBURING is 1, and only skip miniublk
with an explicit message when linux/ublk_cmd.h is missing. For that
purpose, split miniublk from the variable C_URING_TARGETS.

Link: #236
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Signed-off-by: Changhui Zhong <[email protected]>

Author: zhongchanghui

src/Makefile

@@ -22,21 +22,28 @@ C_TARGETS := \
 	sg/syzkaller1 \
 	zbdioctl
 
-C_URING_TARGETS := miniublk \
-		metadata \
-		nvme-passthru-admin-uring
+C_URING_TARGETS := metadata \
+	nvme-passthru-admin-uring
+C_UBLK_TARGETS := miniublk
 
 HAVE_LIBURING := $(call HAVE_C_MACRO,liburing.h,IORING_OP_URING_CMD)
 HAVE_UBLK_HEADER := $(call HAVE_C_HEADER,linux/ublk_cmd.h,1)
 
 CXX_TARGETS := \
 	discontiguous-io
 
-ifeq ($(HAVE_LIBURING)$(HAVE_UBLK_HEADER), 11)
-TARGETS := $(C_TARGETS) $(CXX_TARGETS) $(C_URING_TARGETS)
-else
-$(info Skip $(C_URING_TARGETS) build due to missing kernel header(v6.0+) or liburing(2.2+))
 TARGETS := $(C_TARGETS) $(CXX_TARGETS)
+
+ifeq ($(HAVE_UBLK_HEADER), 1)
+C_URING_TARGETS += $(C_UBLK_TARGETS)
+else
+$(info Skip $(C_UBLK_TARGETS) build due to missing kernel header(v6.0+))
+endif
+
+ifeq ($(HAVE_LIBURING), 1)
+TARGETS += $(C_URING_TARGETS)
+else
+$(info Skip $(C_URING_TARGETS) build due to missing liburing(2.2+))
 endif
 
 CONFIG_DEFS := $(call HAVE_C_HEADER,linux/blkzoned.h,-DHAVE_LINUX_BLKZONED_H)