On Mon, Feb 08, 2021 at 07:30:07PM -0700, Jens Axboe wrote:
> For the generic page cache read helper, use the better variant of checking
> for the need to call filemap_write_and_wait_range() when doing O_DIRECT
> reads. This avoids falling back to the slow path for IOCB_NOWAIT, if there
> are no pages to wait for (or write out).
>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> mm/filemap.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 6a58d50fbd31..c80acb80e8f7 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2643,8 +2643,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
>
> size = i_size_read(inode);
> if (iocb->ki_flags & IOCB_NOWAIT) {
> - if (filemap_range_has_page(mapping, iocb->ki_pos,
> - iocb->ki_pos + count - 1))
> + if (filemap_range_needs_writeback(mapping, iocb->ki_pos,
> + iocb->ki_pos + count - 1))
Please avoid the overy long line, which is trivial to do by using the
normal two tab indent for the continuation.
