[PATCH 07/18] mmc: meson-gx: check return value of sg_copy_[from, to]_buffer

[khilman@baylibre.com (Kevin Hilman)]

Heiner Kallweit <hkallweit1@gmail.com> writes:

> So far it's only checked whether the requested transfer length exceeds
> the bounce buffer size. Instead let's check that sg_copy_[from,to]_buffer
> transferred exactly the number of requested bytes.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Acked-by: Kevin Hilman <khilman@baylibre.com>

> ---
>  drivers/mmc/host/meson-gx-mmc.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
> index 423b4b17..f3963538 100644
> --- a/drivers/mmc/host/meson-gx-mmc.c
> +++ b/drivers/mmc/host/meson-gx-mmc.c
> @@ -495,14 +495,14 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
>  		cmd->data->bytes_xfered = 0;
>  		xfer_bytes = cmd->data->blksz * cmd->data->blocks;
>  		if (cmd->data->flags & MMC_DATA_WRITE) {
> -			cmd_cfg |= CMD_CFG_DATA_WR;
> -			WARN_ON(xfer_bytes > host->bounce_buf_size);
> -			sg_copy_to_buffer(cmd->data->sg, cmd->data->sg_len,
> -					  host->bounce_buf, xfer_bytes);
> +			size_t len = sg_copy_to_buffer(cmd->data->sg,
> +						       cmd->data->sg_len,
> +						       host->bounce_buf,
> +						       host->bounce_buf_size);
> +			WARN_ON(len != xfer_bytes);
>  			cmd->data->bytes_xfered = xfer_bytes;
> +			cmd_cfg |= CMD_CFG_DATA_WR;
>  			dma_wmb();
> -		} else {
> -			cmd_cfg &= ~CMD_CFG_DATA_WR;
>  		}
>  
>  		cmd_data = host->bounce_dma_addr & CMD_DATA_MASK;
> @@ -657,10 +657,11 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
>  
>  	data = cmd->data;
>  	if (data && data->flags & MMC_DATA_READ) {
> +		size_t len = sg_copy_from_buffer(data->sg, data->sg_len,
> +						 host->bounce_buf,
> +						 host->bounce_buf_size);
>  		xfer_bytes = data->blksz * data->blocks;
> -		WARN_ON(xfer_bytes > host->bounce_buf_size);
> -		sg_copy_from_buffer(data->sg, data->sg_len,
> -				    host->bounce_buf, xfer_bytes);
> +		WARN_ON(len != xfer_bytes);
>  		data->bytes_xfered = xfer_bytes;
>  	}