X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=block%2Fblk-map.c;h=c07d9c8317f4c055d3821302c22df20cf2627195;hb=4597a0ce0849eaa62fc9083c21943e0c434e4135;hp=955d75c1a58fd634e3f168ec8d091c4c9e93a965;hpb=8f859016ea49cd8d7c743533bd1ab3db9a813ffa;p=deliverable%2Flinux.git

diff --git a/block/blk-map.c b/block/blk-map.c
index 955d75c1a58f..c07d9c8317f4 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -43,6 +43,7 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
 			     void __user *ubuf, unsigned int len)
 {
 	unsigned long uaddr;
+	unsigned int alignment;
 	struct bio *bio, *orig_bio;
 	int reading, ret;
 
@@ -53,8 +54,8 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
 	 * direct dma. else, set up kernel bounce buffers
 	 */
 	uaddr = (unsigned long) ubuf;
-	if (!(uaddr & queue_dma_alignment(q)) &&
-	    !(len & queue_dma_alignment(q)))
+	alignment = queue_dma_alignment(q) | q->dma_pad_mask;
+	if (!(uaddr & alignment) && !(len & alignment))
 		bio = bio_map_user(q, NULL, uaddr, len, reading);
 	else
 		bio = bio_copy_user(q, uaddr, len, reading);
@@ -139,10 +140,31 @@ 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 to dma_pad_mask.  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 & q->dma_pad_mask) {
+		unsigned int pad_len = (q->dma_pad_mask & ~len) + 1;
+		struct bio *tail = rq->biotail;
+
+		tail->bi_io_vec[tail->bi_vcnt - 1].bv_len += pad_len;
+		tail->bi_size += pad_len;
+
+		rq->extra_len += pad_len;
+	}
+
 	rq->buffer = rq->data = NULL;
 	return 0;
 unmap_rq:
 	blk_rq_unmap_user(bio);
+	rq->bio = NULL;
 	return ret;
 }
 EXPORT_SYMBOL(blk_rq_map_user);
@@ -195,7 +217,6 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 	rq->buffer = rq->data = NULL;
 	return 0;
 }
-EXPORT_SYMBOL(blk_rq_map_user_iov);
 
 /**
  * blk_rq_unmap_user - unmap a request with user data