Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs fixes from Al Viro:
 "Fairly old DIO bug caught by Andreas (3.10+) and several slightly
  younger blk_rq_map_user_iov() bugs, both on map and copy codepaths
  (Vitaly and me)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  bio_copy_user_iov(): don't ignore ->iov_offset
  more bio_map_user_iov() leak fixes
  fix unbalanced page refcounting in bio_map_user_iov
  direct-io: Prevent NULL pointer access in submit_page_section

2 files changed, 21 insertions, 8 deletions

diff --git a/block/bio.c b/block/bio.c
index b38e962fa83e..101c2a9b5481 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1239,8 +1239,8 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
          */
         bmd->is_our_pages = map_data ? 0 : 1;
         memcpy(bmd->iov, iter->iov, sizeof(struct iovec) * iter->nr_segs);
-        iov_iter_init(&bmd->iter, iter->type, bmd->iov,
-                        iter->nr_segs, iter->count);
+        bmd->iter = *iter;
+        bmd->iter.iov = bmd->iov;
 
         ret = -ENOMEM;
         bio = bio_kmalloc(gfp_mask, nr_pages);
@@ -1331,6 +1331,7 @@ struct bio *bio_map_user_iov(struct request_queue *q,
         int ret, offset;
         struct iov_iter i;
         struct iovec iov;
+        struct bio_vec *bvec;
 
         iov_for_each(iov, i, *iter) {
                 unsigned long uaddr = (unsigned long) iov.iov_base;
@@ -1375,7 +1376,12 @@ struct bio *bio_map_user_iov(struct request_queue *q,
                 ret = get_user_pages_fast(uaddr, local_nr_pages,
                                 (iter->type & WRITE) != WRITE,
                                 &pages[cur_page]);
-                if (ret < local_nr_pages) {
+                if (unlikely(ret < local_nr_pages)) {
+                        for (j = cur_page; j < page_limit; j++) {
+                                if (!pages[j])
+                                        break;
+                                put_page(pages[j]);
+                        }
                         ret = -EFAULT;
                         goto out_unmap;
                 }
@@ -1383,6 +1389,7 @@ struct bio *bio_map_user_iov(struct request_queue *q,
                 offset = offset_in_page(uaddr);
                 for (j = cur_page; j < page_limit; j++) {
                         unsigned int bytes = PAGE_SIZE - offset;
+                        unsigned short prev_bi_vcnt = bio->bi_vcnt;
 
                         if (len <= 0)
                                 break;
@@ -1397,6 +1404,13 @@ struct bio *bio_map_user_iov(struct request_queue *q,
                                             bytes)
                                 break;
 
+                        /*
+                         * check if vector was merged with previous
+                         * drop page reference if needed
+                         */
+                        if (bio->bi_vcnt == prev_bi_vcnt)
+                                put_page(pages[j]);
+
                         len -= bytes;
                         offset = 0;
                 }
@@ -1423,10 +1437,8 @@ struct bio *bio_map_user_iov(struct request_queue *q,
         return bio;
 
  out_unmap:
-        for (j = 0; j < nr_pages; j++) {
-                if (!pages[j])
-                        break;
-                put_page(pages[j]);
+        bio_for_each_segment_all(bvec, bio, j) {
+                put_page(bvec->bv_page);
         }
  out:
         kfree(pages);
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 62cf812ed0e5..96415c65bbdc 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -866,7 +866,8 @@ out:
          */
         if (sdio->boundary) {
                 ret = dio_send_cur_page(dio, sdio, map_bh);
-                dio_bio_submit(dio, sdio);
+                if (sdio->bio)
+                        dio_bio_submit(dio, sdio);
                 put_page(sdio->cur_page);
                 sdio->cur_page = NULL;
         }