Re: [PATCH] hw/nvme: fix control flow statement

[Klaus Jensen <its@irrelevant.dk>]

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On Apr 15 13:35, Keith Busch wrote:
> On Fri, Apr 15, 2022 at 10:27:21PM +0300, Dmitry Tikhov wrote:
> > Since there is no else after nvme_dsm_cb invocation, metadata associated
> > with non-zero block range is currently zeroed. Also this behaviour leads
> > to segfault since we schedule iocb->bh two times. First when entering
> > nvme_dsm_cb with iocb->idx == iocb->nr and second on call stack unwinding
> > by calling blk_aio_pwrite_zeroes and subsequent nvme_dsm_cb callback
> > because of missing else statement.
> > 
> > Signed-off-by: Dmitry Tikhov <d.tihov@yadro.com>
> > ---
> >  hw/nvme/ctrl.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
> > index 03760ddeae..7ebd2aa326 100644
> > --- a/hw/nvme/ctrl.c
> > +++ b/hw/nvme/ctrl.c
> > @@ -2372,11 +2372,12 @@ static void nvme_dsm_md_cb(void *opaque, int ret)
> >          }
> >  
> >          nvme_dsm_cb(iocb, 0);
> > +    } else {
> > +        iocb->aiocb = blk_aio_pwrite_zeroes(ns->blkconf.blk, nvme_moff(ns, slba),
> > +                                            nvme_m2b(ns, nlb), BDRV_REQ_MAY_UNMAP,
> > +                                            nvme_dsm_cb, iocb);
> >      }
> 
> Instead of the 'else', just insert an early 'return;' after nvme_dsm_cb() like
> the earlier condition above here. Otherwise, looks good, and thanks for the
> fix.

Dmitry,

Agree with Keith - also, please add

  Fixes: d7d1474fd85d ("hw/nvme: reimplement dsm to allow cancellation")

Thanks again!

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