Re: [RFC][PATCH 0/2] Avoiding DWC3 transfer stalls/hangs when using adb over f_fs

[Christoph Hellwig]

On Thu, Feb 06, 2020 at 08:29:45PM +0200, Felipe Balbi wrote:
> > No, it shoudn't.  dma_map_sg returns the number of mapped segments,
> > and the callers need to remember that.
> 
> We _do_ remember that:

That helps :)

> that req->request.num_mapped_sgs is the returned value. So you're saying
> we should test for i == num_mapped_sgs, instead of using
> sg_is_last(). Is that it?

Yes.

> Fair enough. Just out of curiosity, then, when *should* we use
> sg_is_last()?

Outside of sg_next/sg_last it really shoud not be used at all as far
as I'm concerned.