---

yaml
---
r: 85888
b: refs/heads/master
c: 40b01b9
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 56c819df77f96c3fc0c2a979e12b478403728790
+refs/heads/master: 40b01b9bbdf51ae543a04744283bf2d56c4a6afa

trunk/block/blk-map.c

@@ -139,6 +139,23 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
 		ubuf += ret;
 	}
 
+	/*
+	 * __blk_rq_map_user() copies the buffers if starting address
+	 * or length isn't aligned.  As the copied buffer is always
+	 * page aligned, we know that there's enough room for padding.
+	 * Extend the last bio and update rq->data_len accordingly.
+	 *
+	 * On unmap, bio_uncopy_user() will use unmodified
+	 * bio_map_data pointed to by bio->bi_private.
+	 */
+	if (len & queue_dma_alignment(q)) {
+		unsigned int pad_len = (queue_dma_alignment(q) & ~len) + 1;
+		struct bio *bio = rq->biotail;
+
+		bio->bi_io_vec[bio->bi_vcnt - 1].bv_len += pad_len;
+		bio->bi_size += pad_len;
+	}
+
 	rq->buffer = rq->data = NULL;
 	return 0;
 unmap_rq: