Re: [PATCH v5] usb-storage: Simplify protocol translation

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Oct 08, 2025 at 12:34:20PM +0530, Shi Hao wrote:
> Simplify protocol translation for usb subclasses.
> 
> As suggested by Alan Stern  to remove the switch case labels  with
> 'default'  or keep the  previous  if statements  instead of the switch
> cases and advised  reasonable value when cmnd[0] >= 0xe0 .
> 
> keep  those usb subclasses to default and simplify logic removing
> switch cases and set 6 as a reasonable value when cmnd[0] >= 0xe0
> which fallbacks  to value 6 which is old cmd_len for those subclasses.
> 
> Signed-off-by: Shi Hao <i.shihao.999@gmail.com>
> 
> ---
> 
> changes v5:
> - Reformulate as  v5  of original patch series
> - No code changes ,clarified versioning history
> 
> changes v4:
> - Simplify  protocol translation logic
> - Set reasonable default when cmnd[0] >= 0xE0
> - Remove switch-case statement
> 
> changes v3:
> - Wrap  commit message lines properly
> - Improve commit description
> - fix  checkpatch.pl script errors
> 
> changes v2:
> - Update subject commit message
> - fix  checkpatch.pl warnings
> - match from: and sign-off: name
> ---
>  drivers/usb/storage/transport.c | 21 +++++++--------------
>  1 file changed, 7 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
> index 4d01f70f39ac..14cc608052d9 100644
> --- a/drivers/usb/storage/transport.c
> +++ b/drivers/usb/storage/transport.c
> @@ -719,17 +719,9 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
>  		scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size);
>  
>  		/* 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;
> -			break;
> -		/* Determine cmd_len based on scsi opcode group */
> -		case USB_SC_RBC:
> -		case USB_SC_SCSI:
> -		case USB_SC_CYP_ATACB:
> +		if (us->subclass == USB_SC_RBC || us->subclass == USB_SC_SCSI ||
> +				us->subclass == USB_SC_CYP_ATACB) {
> +		/* Determine cmd_len based on SCSI opcode group */

Always remember to run scripts/checkpatch.pl before sending changes out
to others :(

thanks,

greg k-h