On Tue, May 01, 2018 at 09:22:31AM +0100, Roger Pau Monné wrote:
> On Mon, Apr 30, 2018 at 11:01:50PM +0200, Marek Marczykowski-Górecki wrote:
> > struct request *req,
> > - struct blkif_request **ring_req)
> > + struct blkif_request *ring_req)
> > {
> > unsigned long id;
> >
> > - *ring_req = RING_GET_REQUEST(&rinfo->ring, rinfo->ring.req_prod_pvt);
> > - rinfo->ring.req_prod_pvt++;
> > -
> > id = get_id_from_freelist(rinfo);
> > rinfo->shadow[id].request = req;
> > rinfo->shadow[id].status = REQ_WAITING;
> > rinfo->shadow[id].associated_id = NO_ASSOCIATED_ID;
> >
> > - (*ring_req)->u.rw.id = id;
> > + ring_req->u.rw.id = id;
> >
> > return id;
> > }
> > @@ -545,23 +542,28 @@ static unsigned long blkif_ring_get_request(struct blkfront_ring_info *rinfo,
> > static int blkif_queue_discard_req(struct request *req, struct blkfront_ring_info *rinfo)
> > {
> > struct blkfront_info *info = rinfo->dev_info;
> > - struct blkif_request *ring_req;
> > + struct blkif_request ring_req = { 0 };
> > unsigned long id;
> >
> > /* Fill out a communications ring structure. */
> > id = blkif_ring_get_request(rinfo, req, &ring_req);
>
> Maybe I'm missing something obvious here, but you are adding a struct
> allocated on the stack to the shadow ring copy, isn't this dangerous?
The above comment is wrong, you are storing a pointer to 'req' in the
shadow ring copy, which is fine and is not the ring request.
Roger.
