trivial warn_unused_result squashing

Made the mistake of recompiling the F9 mdadm rpm which has a patch to
remove -Werror and add "-Wp,-D_FORTIFY_SOURCE -O2" which turns on lots
of errors:

config.c:568: warning: ignoring return value of asprintf
Assemble.c:411: warning: ignoring return value of asprintf
Assemble.c:413: warning: ignoring return value of asprintf
super0.c:549: warning: ignoring return value of posix_memalign
super0.c:742: warning: ignoring return value of posix_memalign
super0.c:812: warning: ignoring return value of posix_memalign
super1.c:692: warning: ignoring return value of posix_memalign
super1.c:1039: warning: ignoring return value of posix_memalign
super1.c:1155: warning: ignoring return value of posix_memalign
super-ddf.c:508: warning: ignoring return value of posix_memalign
super-ddf.c:645: warning: ignoring return value of posix_memalign
super-ddf.c:696: warning: ignoring return value of posix_memalign
super-ddf.c:715: warning: ignoring return value of posix_memalign
super-ddf.c:1476: warning: ignoring return value of posix_memalign
super-ddf.c:1603: warning: ignoring return value of posix_memalign
super-ddf.c:1614: warning: ignoring return value of posix_memalign
super-ddf.c:1842: warning: ignoring return value of posix_memalign
super-ddf.c:2013: warning: ignoring return value of posix_memalign
super-ddf.c:2140: warning: ignoring return value of write
super-ddf.c:2143: warning: ignoring return value of write
super-ddf.c:2147: warning: ignoring return value of write
super-ddf.c:2150: warning: ignoring return value of write
super-ddf.c:2162: warning: ignoring return value of write
super-ddf.c:2169: warning: ignoring return value of write
super-ddf.c:2172: warning: ignoring return value of write
super-ddf.c:2176: warning: ignoring return value of write
super-ddf.c:2181: warning: ignoring return value of write
super-ddf.c:2686: warning: ignoring return value of posix_memalign
super-ddf.c:2690: warning: ignoring return value of write
super-ddf.c:3070: warning: ignoring return value of posix_memalign
super-ddf.c:3254: warning: ignoring return value of posix_memalign
bitmap.c:128: warning: ignoring return value of posix_memalign
mdmon.c:94: warning: ignoring return value of write
mdmon.c:221: warning: ignoring return value of pipe
mdmon.c:327: warning: ignoring return value of write
mdmon.c:330: warning: ignoring return value of chdir
mdmon.c:335: warning: ignoring return value of dup
monitor.c:415: warning: rv may be used uninitialized in this function

...some of these like the write() ones are not so trivial so save those
fixes for the next patch.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/Assemble.c b/Assemble.c
index a73e101..c691ec9 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -396,6 +396,8 @@ int Assemble(struct supertype *st, char *mddev, int mdfd,
 		mdu_array_info_t inf;
 		char *c;
 		char nbuf[64];
+		int rc;
+
 		if (!st || !st->sb) {
 			return 2;
 		}
@@ -408,10 +410,13 @@ int Assemble(struct supertype *st, char *mddev, int mdfd,
 		}
 		if (isdigit(*c) && ((ident->autof & 7)==4 || (ident->autof&7)==6))
 			/* /dev/md/d0 style for partitionable */
-			asprintf(&mddev, "/dev/md/d%s", c);
+			rc = asprintf(&mddev, "/dev/md/d%s", c);
+		else
+			rc = asprintf(&mddev, "/dev/md/%s", c);
+		if (rc < 0)
+			mdfd = -1;
 		else
-			asprintf(&mddev, "/dev/md/%s", c);
-		mdfd = open_mddev(mddev, ident->autof);
+			mdfd = open_mddev(mddev, ident->autof);
 		if (mdfd < 0) {
 			st->ss->free_super(st);
 			free(devices);