Re: [PATCH 5/5] virtiofs: Retry request submission from worker context

[Vivek Goyal <vgoyal@redhat.com>]

On Mon, Oct 21, 2019 at 10:15:18AM +0200, Miklos Szeredi wrote:
[..]
> > @@ -268,13 +272,43 @@ static void virtio_fs_request_dispatch_work(struct work_struct *work)
> >                                                list);
> >                 if (!req) {
> >                         spin_unlock(&fsvq->lock);
> > -                       return;
> > +                       break;
> >                 }
> >
> >                 list_del_init(&req->list);
> >                 spin_unlock(&fsvq->lock);
> >                 fuse_request_end(fc, req);
> >         }
> > +
> > +       /* Dispatch pending requests */
> > +       while (1) {
> > +               spin_lock(&fsvq->lock);
> > +               req = list_first_entry_or_null(&fsvq->queued_reqs,
> > +                                              struct fuse_req, list);
> > +               if (!req) {
> > +                       spin_unlock(&fsvq->lock);
> > +                       return;
> > +               }
> > +               list_del_init(&req->list);
> > +               spin_unlock(&fsvq->lock);
> > +
> > +               ret = virtio_fs_enqueue_req(fsvq, req, true);
> > +               if (ret < 0) {
> > +                       if (ret == -ENOMEM || ret == -ENOSPC) {
> > +                               spin_lock(&fsvq->lock);
> > +                               list_add_tail(&req->list, &fsvq->queued_reqs);
> > +                               schedule_delayed_work(&fsvq->dispatch_work,
> > +                                                     msecs_to_jiffies(1));
> > +                               spin_unlock(&fsvq->lock);
> > +                               return;
> > +                       }
> > +                       req->out.h.error = ret;
> > +                       dec_in_flight_req(fsvq);
> 
> Missing locking.  Fixed.

Good catch. Thanks.

Vivek