Re: [PATCH] drivers: rtl818x: request DMA-able memory

[Hin-Tak Leung]

Larry Finger wrote:
> On 10/24/2010 03:32 PM, Serafeim Zanikolas wrote:
> > Despite the indicated intention in comment, the kmalloc() call was not
> > explicitly requesting memory from ZONE_DMA.
> >
> > Signed-off-by: Serafeim Zanikolas <sez@xxxxxxxxxx>
> > ---
> >  drivers/net/wireless/rtl818x/rtl8187_dev.c |    3 ++-
> >  1 files changed, 2 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/net/wireless/rtl818x/rtl8187_dev.c b/drivers/net/wireless/rtl818x/rtl8187_dev.c
> > index 38fa824..771794d 100644
> > --- a/drivers/net/wireless/rtl818x/rtl8187_dev.c
> > +++ b/drivers/net/wireless/rtl818x/rtl8187_dev.c
> > @@ -1343,7 +1343,8 @@ static int __devinit rtl8187_probe(struct usb_interface *intf,
> >  	priv->is_rtl8187b = (id->driver_info == DEVICE_RTL8187B);
> >  
> >  	/* allocate "DMA aware" buffer for register accesses */
> > -	priv->io_dmabuf = kmalloc(sizeof(*priv->io_dmabuf), GFP_KERNEL);
> > +	priv->io_dmabuf = kmalloc(sizeof(*priv->io_dmabuf),
> > +				  GFP_DMA | GFP_KERNEL);
> >  	if (!priv->io_dmabuf) {
> >  		err = -ENOMEM;
> >  		goto err_free_dev;
>
> ACK.
>
> Larry

Acked-by: Hin-Tak Leung <htl10@xxxxxxxxxxxxxxxxxxxxx>

I had a quick look for similiar constructs and AFAIK only the b43/b43legacy 
drivers uses DMA buffers. Seems to be a rare practice. Is that something we 
should or should not do?

Hin-Tak
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