Re: [PATCH 02/15] libata: zero xfer length on ATAPI data xfer IRQ is HSM violation

[Albert Lee <albertcc@tw.ibm.com>]

Tejun Heo wrote:
> From: Albert Lee <albertcc@tw.ibm.com>
> 
> Treat zero xfer length as HSM violation.  While at it, add
> unlikely()'s to ATAPI ireason and transfer length checks.
> 
> tj: Formatted patch and added unlikely()'s.
> 
> Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
> Signed-off-by: Tejun Heo <htejun@gmail.com>
> ---
>  drivers/ata/libata-core.c |    7 +++++--
>  1 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index 597e07c..88f7637 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -5280,12 +5280,15 @@ static void atapi_pio_bytes(struct ata_queued_cmd *qc)
>  	bytes = (bc_hi << 8) | bc_lo;
>  
>  	/* shall be cleared to zero, indicating xfer of data */
> -	if (ireason & (1 << 0))
> +	if (unlikely(ireason & (1 << 0)))
>  		goto err_out;
>  
>  	/* make sure transfer direction matches expected */
>  	i_write = ((ireason & (1 << 1)) == 0) ? 1 : 0;
> -	if (do_write != i_write)
> +	if (unlikely(do_write != i_write))
> +		goto err_out;
> +
> +	if (unlikely(!bytes))
>  		goto err_out;
>  
>  	VPRINTK("ata%u: xfering %d bytes\n", ap->print_id, bytes);


Looks good.

Acked-by: Albert Lee <albertcc@tw.ibm.com>