fix the copy vs. map logics in blk_rq_map_user_iov()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 39 deletions

diff --git a/block/blk-map.c b/block/blk-map.c
index a54f0543b956..b9f88b7751fb 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -9,24 +9,6 @@
 
 #include "blk.h"
 
-static bool iovec_gap_to_prv(struct request_queue *q,
-			     struct iovec *prv, struct iovec *cur)
-{
-	unsigned long prev_end;
-
-	if (!queue_virt_boundary(q))
-		return false;
-
-	if (prv->iov_base == NULL && prv->iov_len == 0)
-		/* prv is not set - don't check */
-		return false;
-
-	prev_end = (unsigned long)(prv->iov_base + prv->iov_len);
-
-	return (((unsigned long)cur->iov_base & queue_virt_boundary(q)) ||
-		prev_end & queue_virt_boundary(q));
-}
-
 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
 		      struct bio *bio)
 {
@@ -125,31 +107,18 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 			struct rq_map_data *map_data,
 			const struct iov_iter *iter, gfp_t gfp_mask)
 {
-	struct iovec iov, prv = {.iov_base = NULL, .iov_len = 0};
-	bool copy = (q->dma_pad_mask & iter->count) || map_data;
+	bool copy = false;
+	unsigned long align = q->dma_pad_mask | queue_dma_alignment(q);
 	struct bio *bio = NULL;
 	struct iov_iter i;
 	int ret;
 
-	if (!iter || !iter->count)
-		return -EINVAL;
-
-	iov_for_each(iov, i, *iter) {
-		unsigned long uaddr = (unsigned long) iov.iov_base;
-
-		if (!iov.iov_len)
-			return -EINVAL;
-
-		/*
-		 * Keep going so we check length of all segments
-		 */
-		if ((uaddr & queue_dma_alignment(q)) ||
-		    iovec_gap_to_prv(q, &prv, &iov))
-			copy = true;
-
-		prv.iov_base = iov.iov_base;
-		prv.iov_len = iov.iov_len;
-	}
+	if (map_data)
+		copy = true;
+	else if (iov_iter_alignment(iter) & align)
+		copy = true;
+	else if (queue_virt_boundary(q))
+		copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);
 
 	i = *iter;
 	do {