Re: [PATCH] usb: fix protocol translation in drivers/usb/storage/transport.c

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Oct 03, 2025 at 04:16:33PM +0530, Shi Hao wrote:
> Previously, only a few USB subclasses had srb->cmd_len translated to 6 or 12 bytes, which was insufficient for some SCSI opcodes. This patch extends translation to the correct opcode ranges so that command lengths are set properly.
> 
> Signed-off-by: Shi Hao <i.shihao.999@gmail.com>
> ---
>  drivers/usb/storage/transport.c | 41 ++++++++++++++++++++++++++++-----
>  1 file changed, 35 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
> index 1aa1bd26c81f..4dd6bfa86c23 100644
> --- a/drivers/usb/storage/transport.c
> +++ b/drivers/usb/storage/transport.c
> @@ -718,12 +718,41 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
>  
>  		scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size);
>  
> -		/* FIXME: we must do the protocol translation here */
> -		if (us->subclass == USB_SC_RBC || us->subclass == USB_SC_SCSI ||
> -				us->subclass == USB_SC_CYP_ATACB)
> -			srb->cmd_len = 6;
> -		else
> -			srb->cmd_len = 12;
> +		/* Protocol translation per SCSI opcode group */
> +                switch(us->subclass)
> +                {
> +                case USB_SC_UFI:
> +                case USB_SC_8020:
> +                case USB_SC_8070:
> +                case USB_SC_QIC:
> +                         srb->cmd_len = 12 ;             /* ATAPI/UFI devices always use 12-byte CDBs */
> +                         break;
> +
> +                case USB_SC_RBC:
> +                case USB_SC_SCSI:
> +                case USB_SC_CYP_ATACB:                   /* Determine cmd_len based on SCSI opcode group */
> +
> +                         if(opcode <= 0x1F)             /* Group 0 */
> +                         {
> +                                 srb->cmd_len = 6 ;
> +                         }else if( opcode <= 0x7F)      /* Group 1 & 2 */
> +                         {
> +                                 srb->cmd_len = 10;
> +                         }else if(opcode <= 0x9F )      /* Group 5 */
> +                         {
> +                                srb->cmd_len = 16 ;
> +                         }else if(opcode <=0xBF)        /* Group 6 */
> +                         {
> +                                srb->cmd_len = 12 ;
> +                         }else if( opcode <=0xDF)       /* Group 7 */
> +                         {
> +                                srb->cmd_len = 16;
> +                         }else{
> +                                ;                       /* Leaving cmd_len  value unchanged  for  0xE0–0xFF vendor-specific*/
> +
> +                         }
> +                        break;
> +                }
>  
>  		/* issue the auto-sense command */
>  		scsi_set_resid(srb, 0);
> -- 
> 2.51.0
> 
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
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