Re: [PATCH 4/9 next] fs/io_uring Don't use the return value from import_iovec().

[Christoph Hellwig <hch@infradead.org>]

On Tue, Sep 15, 2020 at 02:55:20PM +0000, David Laight wrote:
> 
> This is the only code that relies on import_iovec() returning
> iter.count on success.
> This allows a better interface to import_iovec().

This looks generall sane, but a comment below:

> @@ -3123,7 +3123,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
>  	if (ret < 0)
>  		return ret;
>  	iov_count = iov_iter_count(iter);
> -	io_size = ret;
> +	io_size = iov_count;
>  	req->result = io_size;
>  	ret = 0;
>  
> @@ -3246,7 +3246,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
>  	if (ret < 0)
>  		return ret;
>  	iov_count = iov_iter_count(iter);
> -	io_size = ret;
> +	io_size = iov_count;
>  	req->result = io_size;

I tink the local iov_count variable can go away in both functions,
as io_size only changes after the last use of iov_count (io_read) or
not at all (io_write).