Re: [PATCH v2 27/27] sound: ppc: remove unneeded memset after dma_alloc_coherent

[Christophe Leroy]

Le 28/06/2019 Ã 11:11, Fuqian Huang a ÃcritÂ:
> The merge commit log tells (dma-mapping: zero memory returned from
> dma_alloc_* and deprecating the dma_zalloc_coherent).
> I used this commit just want to say that dma_alloc_coherent  has
> zeroed the allocated memory.
> Sorry for this mistake.
>
> Maybe this commit 518a2f1925c3("dma-mapping: zero memory returned from
> dma_alloc_*") is correct.

Yes that looks appropriate. And it confirms it was already done on 
powerpc, as that patch doesn't include any change in powerpc arch.

Christophe

> Christophe Leroy <christophe.leroy@xxxxxx> æ 2019å6æ28æéä äå4:59åéï
>
> > Le 28/06/2019 Ã 04:50, Fuqian Huang a Ãcrit :
> > > In commit af7ddd8a627c
> > > ("Merge tag 'dma-mapping-4.21' of git://git.infradead.org/users/hch/dma-mapping"),
> > > dma_alloc_coherent has already zeroed the memory.
> > > So memset is not needed.
> >
> > You are refering to a merge commit, is that correct ?
> >
> > I can't see anything related in that commit, can you please pinpoint it ?
> >
> > As far as I can see, on powerpc the memory has always been zeroized
> > (since 2005 at least).
> >
> > Christophe
> >
> > > Signed-off-by: Fuqian Huang <huangfq.daxian@xxxxxxxxx>
> > > ---
> > >    sound/ppc/pmac.c | 1 -
> > >    1 file changed, 1 deletion(-)
> > >
> > > diff --git a/sound/ppc/pmac.c b/sound/ppc/pmac.c
> > > index 1b11e53f6a62..1ab12f4f8631 100644
> > > --- a/sound/ppc/pmac.c
> > > +++ b/sound/ppc/pmac.c
> > > @@ -56,7 +56,6 @@ static int snd_pmac_dbdma_alloc(struct snd_pmac *chip, struct pmac_dbdma *rec, i
> > >        if (rec->space == NULL)
> > >                return -ENOMEM;
> > >        rec->size = size;
> > > -     memset(rec->space, 0, rsize);
> > >        rec->cmds = (void __iomem *)DBDMA_ALIGN(rec->space);
> > >        rec->addr = rec->dma_base + (unsigned long)((char *)rec->cmds - (char *)rec->space);