bio_map_user_iov(): move alignment check into the main loop

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

diff --git a/block/bio.c b/block/bio.c
index fe40948d62afd7d4e02b8833e211ee900dd29d9d..d851f68727f1797edfae1829e743654edd848922 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1344,11 +1344,6 @@ struct bio *bio_map_user_iov(struct request_queue *q,
                        return ERR_PTR(-EINVAL);
 
                nr_pages += end - start;
-               /*
-                * buffer must be aligned to at least logical block size for now
-                */
-               if (uaddr & queue_dma_alignment(q))
-                       return ERR_PTR(-EINVAL);
        }
 
        if (!nr_pages)
@@ -1373,29 +1368,34 @@ struct bio *bio_map_user_iov(struct request_queue *q,
 
                npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
 
-               for (j = 0; j < npages; j++) {
-                       unsigned int n = PAGE_SIZE - offs;
-                       unsigned short prev_bi_vcnt = bio->bi_vcnt;
-
-                       if (n > bytes)
-                               n = bytes;
-
-                       if (!bio_add_pc_page(q, bio, pages[j], n, offs))
-                               break;
-
-                       /*
-                        * check if vector was merged with previous
-                        * drop page reference if needed
-                        */
-                       if (bio->bi_vcnt == prev_bi_vcnt)
-                               put_page(pages[j]);
-
-                       added += n;
-                       bytes -= n;
-                       offs = 0;
+               if (unlikely(offs & queue_dma_alignment(q))) {
+                       ret = -EINVAL;
+                       j = 0;
+               } else {
+                       for (j = 0; j < npages; j++) {
+                               struct page *page = pages[j];
+                               unsigned int n = PAGE_SIZE - offs;
+                               unsigned short prev_bi_vcnt = bio->bi_vcnt;
+
+                               if (n > bytes)
+                                       n = bytes;
+
+                               if (!bio_add_pc_page(q, bio, page, n, offs))
+                                       break;
+
+                               /*
+                                * check if vector was merged with previous
+                                * drop page reference if needed
+                                */
+                               if (bio->bi_vcnt == prev_bi_vcnt)
+                                       put_page(page);
+
+                               added += n;
+                               bytes -= n;
+                               offs = 0;
+                       }
+                       iov_iter_advance(&i, added);
                }
-               iov_iter_advance(&i, added);
-
                /*
                 * release the pages we didn't map into the bio, if any
                 */