Re: [PATCH] net: ethernet: fs-enet: remove casting dma_alloc_coherent

[Christophe Leroy]

Le 11/12/2020 à 17:07, David Laight a écrit :
> From: Christophe Leroy
> > Sent: 11 December 2020 15:22
> >
> > Le 11/12/2020 à 09:52, Xu Wang a écrit :
> > > Remove casting the values returned by dma_alloc_coherent.
> >
> > Can you explain more in the commit log ?
> >
> > As far as I can see, dma_alloc_coherent() doesn't return __iomem, and ring_base member is __iomem
>
> Which is probably wrong - that is the kernel address of kernel memory.
> So it shouldn't have the __iomem marker.

That's where the buffer descriptors are, the driver accesses to the content of the buffer 
descriptors using the IO accessors in_be16()/out_be16(). Is it not correct ?

Christophe

> I wonder what else is wrong....
>
> 	David
>
> > Christophe
> >
> > > Signed-off-by: Xu Wang <vulab@xxxxxxxxxxx>
> > > ---
> > >    drivers/net/ethernet/freescale/fs_enet/mac-fec.c | 2 +-
> > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/ethernet/freescale/fs_enet/mac-fec.c
> > b/drivers/net/ethernet/freescale/fs_enet/mac-fec.c
> > > index 99fe2c210d0f..3ae345676e50 100644
> > > --- a/drivers/net/ethernet/freescale/fs_enet/mac-fec.c
> > > +++ b/drivers/net/ethernet/freescale/fs_enet/mac-fec.c
> > > @@ -131,7 +131,7 @@ static int allocate_bd(struct net_device *dev)
> > >    	struct fs_enet_private *fep = netdev_priv(dev);
> > >    	const struct fs_platform_info *fpi = fep->fpi;
> > >
> > > -	fep->ring_base = (void __force __iomem *)dma_alloc_coherent(fep->dev,
> > > +	fep->ring_base = dma_alloc_coherent(fep->dev,
> > >    					    (fpi->tx_ring + fpi->rx_ring) *
> > >    					    sizeof(cbd_t), &fep->ring_mem_addr,
> > >    					    GFP_KERNEL);
>
> -
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