Re: Return of PENDING status to SCSI driver

Ramya Desai
2009-06-15T14:07:36Z

On 6/15/09, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Mon, 15 Jun 2009, Boaz Harrosh wrote:
>
> > >> If you are using the existing USB mass storage infrastructure then
> > >> it will not work. This is because all commands are issued from a
> > >> thread per host, which does a synchronous execution of one command
> > >> at a time. In fact it does not even have a Q, but a global one cmnd
> > >> pointer per host. And therefor sets can_queue to 1.
> > >>
> > >> Are you using the existing USB infrastructure?
> > >>
> > >>
> > >> Boaz
> > >>
> > > I am replacing the default USB mass storage driver with the one I am
> > > developing. But I am using the default SCSI and USB stack provided by
> > > Linux.
> > >
> > > So is there any another way to make my driver asynchronous?
> > >
> > > -RD
> >
> > I was afraid so.
> >
> > There is a lot of code you will need to change in current USB storage stack
> > SCSI is built with native support for queuing, but not so USB-storage-stack.
>
>
> Boaz:
>
> It looks like you didn't read Ramya's reply to your last message.
> Ramya isn't keeping the USB storage "stack" -- it is being replaced by
> a new driver -- so there's no point talking about making changes to it.
>
>
> Alan Stern
>
>

I already have an array length of 10 for the bellow members.
struct scsi_cmnd *srb; /* current srb */
unsigned int tag; /* current dCBWTag */

I am maintaining an internal queue for the commands.
My main problem is , I am not getting the next command in my USB
storage driver ( My custom) , until the first command is done.
How can I get the next command, while processing the first command?

-Ramya