[LTP] [PATCH 2/2] scsi_debug/tlibio/lio_read_buffer: Always return total amount of read bytes

Petr Vorel pvorel@suse.cz
Wed May 17 02:24:56 CEST 2023


> This issue behind this patch is noticed while fixing the
> lio_write_buffer().

> Here in lio_read_buffer() we have similar situation: in case of a
> partial read, we cycle, but lio_read_buffer() returns back the amount of
> bytes read during the last read() call while it's expected to return the
> whole amount of read bytes.

> Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
> ---
>  lib/tlibio.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

> diff --git a/lib/tlibio.c b/lib/tlibio.c
> index 8298e2de9..604663307 100644
> --- a/lib/tlibio.c
> +++ b/lib/tlibio.c
> @@ -1112,6 +1112,8 @@ int lio_read_buffer(int fd,	/* open file descriptor */
>  		long wrd)	/* to allow future features, use zero for now */
>  {
>  	int ret = 0;		/* syscall return or used to get random method */
> +	int totally_read = 0;	/* as we cycle reads in case of partial reads, */
> +				/* we have to report up total bytes read */

Again, multiline comment would be more readable:

	/* as we cycle reads in case of partial reads,
	 * we have to report up total bytes read */
	int totally_read = 0;

Reviewed-by: Petr Vorel <pvorel@suse.cz>

Kind regards,
Petr

>  	char *io_type;		/* Holds string of type of io */
>  	int listio_cmd;		/* Holds the listio/lio_listio cmd */
>  	int omethod = method;
> @@ -1323,13 +1325,14 @@ int lio_read_buffer(int fd,	/* open file descriptor */
>  						fd, size, ret);
>  					size -= ret;
>  					buffer += ret;
> +					totally_read += ret;
>  				} else {
>  					if (Debug_level > 1)
>  						printf
>  						    ("DEBUG %s/%d: read completed without error (ret %d)\n",
>  						     __FILE__, __LINE__, ret);

> -					return ret;
> +					return totally_read + ret;
>  				}
>  			}
>  			wait4sync_io(fd, 1);


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