libbb/loop.c: style and readability fixes, no code changes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/libbb/loop.c b/libbb/loop.c
index 3fec7ad..a11933f 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -56,14 +56,16 @@
 {
 	int fd;
 	bb_loop_info loopinfo;
-	char *dev = 0;
+	char *dev = NULL;
 
 	fd = open(device, O_RDONLY);
-	if (fd < 0) return 0;
-	if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo))
-		dev = xasprintf("%ld %s", (long) loopinfo.lo_offset,
-				(char *)loopinfo.lo_file_name);
-	close(fd);
+	if (fd >= 0) {
+		if (ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo) == 0) {
+			dev = xasprintf("%lu %s", (long) loopinfo.lo_offset,
+					(char *)loopinfo.lo_file_name);
+		}
+		close(fd);
+	}
 
 	return dev;
 }
@@ -73,7 +75,8 @@
 	int fd, rc;
 
 	fd = open(device, O_RDONLY);
-	if (fd < 0) return 1;
+	if (fd < 0)
+		return 1;
 	rc = ioctl(fd, LOOP_CLR_FD, 0);
 	close(fd);
 
@@ -110,7 +113,7 @@
 		sprintf(dev, LOOP_FORMAT, i);
 
 		/* Ran out of block devices, return failure.  */
-		if (stat(try, &statbuf) || !S_ISBLK(statbuf.st_mode)) {
+		if (stat(try, &statbuf) != 0 || !S_ISBLK(statbuf.st_mode)) {
 			rc = -ENOENT;
 			break;
 		}
@@ -131,8 +134,8 @@
 			safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
 			loopinfo.lo_offset = offset;
 			/* Associate free loop device with file.  */
-			if (!ioctl(dfd, LOOP_SET_FD, ffd)) {
-				if (!ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo))
+			if (ioctl(dfd, LOOP_SET_FD, ffd) == 0) {
+				if (ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo) == 0)
 					rc = 0;
 				else
 					ioctl(dfd, LOOP_CLR_FD, 0);
@@ -143,8 +146,10 @@
 		   file isn't pretty either.  In general, mounting the same file twice
 		   without using losetup manually is problematic.)
 		 */
-		} else if (strcmp(file, (char *)loopinfo.lo_file_name) != 0
-		|| offset != loopinfo.lo_offset) {
+		} else
+		if (strcmp(file, (char *)loopinfo.lo_file_name) != 0
+		 || offset != loopinfo.lo_offset
+		) {
 			rc = -1;
 		}
 		close(dfd);
@@ -152,7 +157,7 @@
 		if (*device) break;
 	}
 	close(ffd);
-	if (!rc) {
+	if (rc == 0) {
 		if (!*device)
 			*device = xstrdup(dev);
 		return (mode == O_RDONLY); /* 1:ro, 0:rw */