On Fri, May 22, 2020 at 07:38:31AM -0500, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>
> Export generic_file_buffered_read() to be used to
> supplement incomplete direct reads.
>
> While we are at it, correct the comments and variable names.
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
> Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> ---
> include/linux/fs.h | 2 ++
> mm/filemap.c | 13 +++++++------
> 2 files changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 45cc10cdf6dd..366c533d30cd 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3124,6 +3124,8 @@ extern int generic_file_rw_checks(struct file *file_in, struct file *file_out);
> extern int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
> struct file *file_out, loff_t pos_out,
> size_t *count, unsigned int flags);
> +extern ssize_t generic_file_buffered_read(struct kiocb *iocb,
> + struct iov_iter *to, ssize_t already_read);
> extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
> extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
> extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 23a051a7ef0f..27df1cf35eb4 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1979,7 +1979,7 @@ static void shrink_readahead_size_eio(struct file_ra_state *ra)
> * generic_file_buffered_read - generic file read routine
> * @iocb: the iocb to read
> * @iter: data destination
> - * @written: already copied
> + * @copied: already copied
> *
> * This is a generic file read routine, and uses the
> * mapping->a_ops->readpage() function for the actual low-level stuff.
> @@ -1988,11 +1988,11 @@ static void shrink_readahead_size_eio(struct file_ra_state *ra)
> * of the logic when it comes to error handling etc.
> *
> * Return:
> - * * total number of bytes copied, including those the were already @written
> + * * total number of bytes copied, including those that were @copied
> * * negative error code if nothing was copied
> */
> -static ssize_t generic_file_buffered_read(struct kiocb *iocb,
> - struct iov_iter *iter, ssize_t written)
> +ssize_t generic_file_buffered_read(struct kiocb *iocb,
> + struct iov_iter *iter, ssize_t copied)
> {
> struct file *filp = iocb->ki_filp;
> struct address_space *mapping = filp->f_mapping;
> @@ -2133,7 +2133,7 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb,
> prev_offset = offset;
>
> put_page(page);
> - written += ret;
> + copied += ret;
> if (!iov_iter_count(iter))
> goto out;
> if (ret < nr) {
> @@ -2241,8 +2241,9 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb,
>
> *ppos = ((loff_t)index << PAGE_SHIFT) + offset;
> file_accessed(filp);
> - return written ? written : error;
> + return copied ? copied : error;
> }
> +EXPORT_SYMBOL_GPL(generic_file_buffered_read);
The renamed variable causes build issues with block tree so I've
s/copied/written/ back as we want only the function export.
