[LTP] [PATCH 1/2] ioprio: use ioprio.h kernel header if it exists

[Damien Le Moal]

For the ioprio system call test cases, avoid blindly defining the
IOPRIO_XXX macro internally and instead use the kernel user API header
file if it exists. Given that the definitions in this header file have
changed over time, make sure to test for the existence of the macro
IOPRIO_PRIO_LEVEL macro and define it if it does not exist. Similarly,
use IOPRIO_NR_LEVELS to define IOPRIO_PRIO_NUM if that macro exists.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 configure.ac                              |  1 +
 testcases/kernel/syscalls/ioprio/ioprio.h | 29 +++++++++++++++++------
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index 548288310..e4aa2cadf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -56,6 +56,7 @@ AC_CHECK_HEADERS_ONCE([ \
     linux/if_ether.h \
     linux/if_packet.h \
     linux/io_uring.h \
+    linux/ioprio.h \
     linux/keyctl.h \
     linux/mempolicy.h \
     linux/module.h \
diff --git a/testcases/kernel/syscalls/ioprio/ioprio.h b/testcases/kernel/syscalls/ioprio/ioprio.h
index c74380475..6ca134a54 100644
--- a/testcases/kernel/syscalls/ioprio/ioprio.h
+++ b/testcases/kernel/syscalls/ioprio/ioprio.h
@@ -6,6 +6,12 @@
 #ifndef LTP_IOPRIO_H
 #define LTP_IOPRIO_H
 
+#ifdef HAVE_LINUX_IOPRIO_H
+
+# include <linux/ioprio.h>
+
+#else
+
 enum {
 	IOPRIO_CLASS_NONE = 0,
 	IOPRIO_CLASS_RT,
@@ -19,15 +25,24 @@ enum {
 	IOPRIO_WHO_USER,
 };
 
-/* The I/O scheduler classes have 8 priorities 0..7 except for the IDLE class */
-#define IOPRIO_PRIO_NUM		8
+# define IOPRIO_CLASS_SHIFT	(13)
+# define IOPRIO_PRIO_MASK	((1UL << IOPRIO_CLASS_SHIFT) - 1)
+
+# define IOPRIO_PRIO_CLASS(data)	((data) >> IOPRIO_CLASS_SHIFT)
+# define IOPRIO_PRIO_VALUE(class, data)	(((class) << IOPRIO_CLASS_SHIFT) | data)
 
-#define IOPRIO_CLASS_SHIFT	(13)
-#define IOPRIO_PRIO_MASK	((1UL << IOPRIO_CLASS_SHIFT) - 1)
+#endif
+
+/* The RT and BE I/O priority classes have 8 priority levels 0..7 */
+#ifdef IOPRIO_NR_LEVELS
+# define IOPRIO_PRIO_NUM		IOPRIO_NR_LEVELS
+#else
+# define IOPRIO_PRIO_NUM		8
+#endif
 
-#define IOPRIO_PRIO_CLASS(data)	((data) >> IOPRIO_CLASS_SHIFT)
-#define IOPRIO_PRIO_LEVEL(data)	((data) & IOPRIO_PRIO_MASK)
-#define IOPRIO_PRIO_VALUE(class, data)	(((class) << IOPRIO_CLASS_SHIFT) | data)
+#ifndef IOPRIO_PRIO_LEVEL
+# define IOPRIO_PRIO_LEVEL(data)	((data) & IOPRIO_PRIO_MASK)
+#endif
 
 static const char * const to_class_str[] = {
 	[IOPRIO_CLASS_NONE] = "NONE",
-- 
2.40.1