Merge tag 'iter-ubuf.2-2023-04-21' of git://git.kernel.dk/linux

Pull ITER_UBUF updates from Jens Axboe:
 "This turns singe vector imports into ITER_UBUF, rather than
  ITER_IOVEC.

  The former is more trivial to iterate and advance, and hence a bit
  more efficient. From some very unscientific testing, ~60% of all iovec
  imports are single vector"

* tag 'iter-ubuf.2-2023-04-21' of git://git.kernel.dk/linux:
  iov_iter: Mark copy_compat_iovec_from_user() noinline
  iov_iter: import single vector iovecs as ITER_UBUF
  iov_iter: convert import_single_range() to ITER_UBUF
  iov_iter: overlay struct iovec and ubuf/len
  iov_iter: set nr_segs = 1 for ITER_UBUF
  iov_iter: remove iov_iter_iovec()
  iov_iter: add iter_iov_addr() and iter_iov_len() helpers
  ALSA: pcm: check for user backed iterator, not specific iterator type
  IB/qib: check for user backed iterator, not specific iterator type
  IB/hfi1: check for user backed iterator, not specific iterator type
  iov_iter: add iter_iovec() helper
  block: ensure bio_alloc_map_data() deals with ITER_UBUF correctly

1 files changed, 8 insertions, 3 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 5cc5a1faaef5..f649647392e0 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3730,10 +3730,15 @@ static int check_direct_read(struct btrfs_fs_info *fs_info,
 	if (!iter_is_iovec(iter))
 		return 0;
 
-	for (seg = 0; seg < iter->nr_segs; seg++)
-		for (i = seg + 1; i < iter->nr_segs; i++)
-			if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
+	for (seg = 0; seg < iter->nr_segs; seg++) {
+		for (i = seg + 1; i < iter->nr_segs; i++) {
+			const struct iovec *iov1 = iter_iov(iter) + seg;
+			const struct iovec *iov2 = iter_iov(iter) + i;
+
+			if (iov1->iov_base == iov2->iov_base)
 				return -EINVAL;
+		}
+	}
 	return 0;
 }