On Wed, 13 Jul 2005, Alan Stern wrote:
> On Sun, 10 Jul 2005, Pete Zaitcev wrote:
>
> > Hi, All:
> >
> > I've refactored the friends of usb_sg_request to permit it being used
> > by ub. The result is attached FYI. It's probably buggy. I cannot convince
> > myself that all this is correct.
> >
> > In case anyone is curious, fields in usb_sg_request were renamed because
> > their functions morphed in a way which made some of uses incorrect for
> > each of them. The renaming ensures that programmer examines every use.
>
> In general this looks pretty good. I didn't read through your changes to
> ub, just to the usb_sg library. Here's what I noticed:
I forgot to mention a couple of other things. In usb_sg_submit you
commented out the call to usb_sg_cancel when a submission fails. I think
you should leave it in. After all, there's no point waiting for the first
few URBs to complete normally if you already know that the transfer as a
whole is doomed.
There's a lot of duplicated code in usb_sg_wait and usb_sg_submit. When
you're confident that the new code works okay, you could simplify
usb_sg_wait to this:
void usb_sg_wait (struct usb_sg_request *io)
{
struct completion done;
init_completion (&done);
io->complete = sg_complete_sync;
io->context = &done;
if (usb_sg_submit (io) == 0)
wait_for_completion (&done);
sg_clean (io);
}
However this ignores the matter of retrying submissions that fail with
-ENXIO, -EAGAIN, or -ENOMEM. Maybe you could add an additional argument
to usb_sg_submit to specify whether such failures should be retried.
Alan Stern
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