Re: [patch 11/12] drivers/block/umem.c: Use the DMA_{64, 32}BIT_MASK constants

[Neil Brown <neilb@cse.unsw.edu.au>]

On Tuesday June 21, axboe@suse.de wrote:
> On Mon, Jun 20 2005, domen@coderock.org wrote:
> > From: Tobias Klauser <tklauser@nuerscht.ch>
> > 
> > 
> > 
> > Use the DMA_{64,32}BIT_MASK constants from dma-mapping.h when calling
> > pci_set_dma_mask() or pci_set_consistent_dma_mask()
> > These patches include dma-mapping.h explicitly because it caused errors
> > on some architectures otherwise.
> > See http://marc.theaimsgroup.com/?t=108001993000001&r=1&w=2 for details
> > 
> > Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
> > Signed-off-by: Domen Puncer <domen@coderock.org>
> > ---
> >  umem.c |    5 +++--
> >  1 files changed, 3 insertions(+), 2 deletions(-)
> > 
> > Index: quilt/drivers/block/umem.c
> > ===================================================================
> > --- quilt.orig/drivers/block/umem.c
> > +++ quilt/drivers/block/umem.c
> > @@ -50,6 +50,7 @@
> >  #include <linux/timer.h>
> >  #include <linux/pci.h>
> >  #include <linux/slab.h>
> > +#include <linux/dma-mapping.h>
> >  
> >  #include <linux/fcntl.h>        /* O_ACCMODE */
> >  #include <linux/hdreg.h>  /* HDIO_GETGEO */
> > @@ -892,8 +893,8 @@ static int __devinit mm_pci_probe(struct
> >  	printk(KERN_INFO "Micro Memory(tm) controller #%d found at %02x:%02x (PCI Mem Module (Battery Backup))\n",
> >  	       card->card_number, dev->bus->number, dev->devfn);
> >  
> > -	if (pci_set_dma_mask(dev, 0xffffffffffffffffLL) &&
> > -	    !pci_set_dma_mask(dev, 0xffffffffLL)) {
> > +	if (pci_set_dma_mask(dev, DMA_64BIT_MASK) &&
> > +	    !pci_set_dma_mask(dev, DMA_32BIT_MASK)) {
> >  		printk(KERN_WARNING "MM%d: NO suitable DMA found\n",num_cards);
> >  		return  -ENOMEM;
> >  	}
> 
> Not from your patch, but that code looks a little strange. We error if
> setting a 64-bit mask fails _but_ the 32-bit one succeeds? That can't be
> right.

No, it can't be, can it.... I remember looking at that code in late
2001 (I think) and thought I could make sense of it, but I'm not so
sure now.

Phap: (if you are still at umem.com) do you remember the rationale
behind this??  
If not, we should probably just remove that '!'...

Thanks Jens,

NeilBrown
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