[PATCH 1/3] src/feature: add IO_URING feature checking

[Zorro Lang <zlang@redhat.com>]

IO_URING is a new feature for GNU/Linux system, if someone case of
xfstests tests this feature, better to check if current system
supports it, or need _notrun.

Signed-off-by: Zorro Lang <zlang@redhat.com>
---
 src/Makefile  |  4 ++++
 src/feature.c | 41 ++++++++++++++++++++++++++++++++++++++---
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index 643c1916..f1422c5c 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -65,6 +65,10 @@ SUBDIRS += aio-dio-regress
 LLDLIBS += -laio
 endif
 
+ifeq ($(HAVE_URING), true)
+LLDLIBS += -luring
+endif
+
 CFILES = $(TARGETS:=.c)
 LDIRT = $(TARGETS) fssum
 
diff --git a/src/feature.c b/src/feature.c
index a7eb7595..df550cf6 100644
--- a/src/feature.c
+++ b/src/feature.c
@@ -19,6 +19,7 @@
  *
  * Test for machine features
  *   -A  test whether AIO syscalls are available
+ *   -R  test whether IO_URING syscalls are available
  *   -o  report a number of online cpus
  *   -s  report pagesize
  *   -w  report bits per long
@@ -39,6 +40,10 @@
 #include <libaio.h>
 #endif
 
+#ifdef HAVE_LIBURING_H
+#include <liburing.h>
+#endif
+
 #ifndef USRQUOTA
 #define USRQUOTA  0
 #endif
@@ -59,7 +64,7 @@ usage(void)
 	fprintf(stderr, "Usage: feature [-v] -<q|u|g|p|U|G|P> <filesystem>\n");
 	fprintf(stderr, "       feature [-v] -c <file>\n");
 	fprintf(stderr, "       feature [-v] -t <file>\n");
-	fprintf(stderr, "       feature -A | -o | -s | -w\n");
+	fprintf(stderr, "       feature -A | -R | -o | -s | -w\n");
 	exit(1);
 }
 
@@ -215,6 +220,29 @@ check_aio_support(void)
 #endif
 }
 
+static int
+check_uring_support(void)
+{
+#ifdef HAVE_LIBURING_H
+	struct io_uring ring;
+	int err;
+
+	err = io_uring_queue_init(1, &ring, 0);
+	if (err == 0)
+		return 0;
+
+	if (err == -ENOSYS) /* CONFIG_IO_URING=n */
+		return 1;
+
+	fprintf(stderr, "unexpected error from io_uring_queue_init(): %s\n",
+		strerror(-err));
+	return 2;
+#else
+	/* liburing is unavailable, assume IO_URING is unsupported */
+	return 1;
+#endif
+}
+
 
 int
 main(int argc, char **argv)
@@ -228,6 +256,7 @@ main(int argc, char **argv)
 	int	pflag = 0;
 	int	Pflag = 0;
 	int	qflag = 0;
+	int	Rflag = 0;
 	int	sflag = 0;
 	int	uflag = 0;
 	int	Uflag = 0;
@@ -235,7 +264,7 @@ main(int argc, char **argv)
 	int	oflag = 0;
 	char	*fs = NULL;
 
-	while ((c = getopt(argc, argv, "ActgGopPqsuUvw")) != EOF) {
+	while ((c = getopt(argc, argv, "ActgGopPqRsuUvw")) != EOF) {
 		switch (c) {
 		case 'A':
 			Aflag++;
@@ -264,6 +293,9 @@ main(int argc, char **argv)
 		case 'q':
 			qflag++;
 			break;
+		case 'R':
+			Rflag++;
+			break;
 		case 's':
 			sflag++;
 			break;
@@ -289,7 +321,7 @@ main(int argc, char **argv)
 		if (optind != argc-1)	/* need a device */
 			usage();
 		fs = argv[argc-1];
-	} else if (Aflag || wflag || sflag || oflag) {
+	} else if (Aflag || Rflag || wflag || sflag || oflag) {
 		if (optind != argc)
 			usage();
 	} else 
@@ -317,6 +349,9 @@ main(int argc, char **argv)
 	if (Aflag)
 		return(check_aio_support());
 
+	if (Rflag)
+		return(check_uring_support());
+
 	if (sflag) {
 		printf("%d\n", getpagesize());
 		exit(0);
-- 
2.20.1