Re: [linux-next PATCH] rapidio: Fix error handling path

[Ira Weiny]

On Wed, Sep 16, 2020 at 09:12:17AM +0530, Souptick Joarder wrote:
> There is an error when pin_user_pages_fast() returns -ERRNO and
> inside error handling path driver end up calling unpin_user_pages()
> with -ERRNO which is not correct.
> 
> This patch will fix the problem.
> 
> Fixes: e8de370188d09 ("rapidio: add mport char device driver")
> Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
> Cc: Ira Weiny <ira.weiny@xxxxxxxxx>

Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>

> Cc: John Hubbard <jhubbard@xxxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> ---
>  drivers/rapidio/devices/rio_mport_cdev.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c
> index a303429..163b6c72 100644
> --- a/drivers/rapidio/devices/rio_mport_cdev.c
> +++ b/drivers/rapidio/devices/rio_mport_cdev.c
> @@ -871,15 +871,16 @@ static int do_dma_request(struct mport_dma_req *req,
>  				rmcd_error("pin_user_pages_fast err=%ld",
>  					   pinned);
>  				nr_pages = 0;
> -			} else
> +			} else {
>  				rmcd_error("pinned %ld out of %ld pages",
>  					   pinned, nr_pages);
> +				/*
> +				 * Set nr_pages up to mean "how many pages to unpin, in
> +				 * the error handler:
> +				 */
> +				nr_pages = pinned;
> +			}
>  			ret = -EFAULT;
> -			/*
> -			 * Set nr_pages up to mean "how many pages to unpin, in
> -			 * the error handler:
> -			 */
> -			nr_pages = pinned;
>  			goto err_pg;
>  		}
>  
> -- 
> 1.9.1
>