On Mon, 4 Jan 2021 10:37:12 -0800
Keith Busch <kbusch@xxxxxxxxxx> wrote:
> On Mon, Jan 04, 2021 at 07:56:11PM +0200, Lauri Kasanen wrote:
> > +static blk_status_t get_seg(struct request *req)
> > +{
> > + u32 bstart = blk_rq_pos(req) * 512;
> > + u32 len = blk_rq_cur_bytes(req);
> > + void *dst = bio_data(req->bio);
...
> > + memcpy(dst, buf, curlen);
>
> Is there a reason for using a bounce buffer rather than reading directly
> into the destination?
DMA alignment restrictions, I wasn't sure what guarantees the bio data
buffers have. Or even if they are guaranteed to be X-aligned virtually,
whether it holds physically.
- Lauri
