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

[Klaus Jensen <its@irrelevant.dk>]

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On Apr 15 23:23, Dmitry Tikhov wrote:
> On Fri, Apr 15, 2022 at 21:42:05, Klaus Jensen wrote:
> > 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!
> 
> Ok, will do. Can i change patch subject text or it should stay
> the same between submissions?

Changing it is ok :)

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