block: make bio_rw_flagged() return a bool

Makes for a saner interface, instead of returning the bit position.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/bio.h b/include/linux/bio.h
index a299ed3..4f8fd02 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -177,7 +177,10 @@
 	BIO_RW_NOIDLE,
 };
 
-#define bio_rw_flagged(bio, flag)	((bio)->bi_rw & (1 << (flag)))
+static inline bool bio_rw_flagged(struct bio *bio, enum bio_rw_flags flag)
+{
+	return (bio->bi_rw & (1 << flag)) != 0;
+}
 
 /*
  * Old defines, these should eventually be replaced by direct usage of