Messages in this thread | | | Date | Thu, 16 Aug 2001 14:03:17 +0200 | From | Jens Axboe <> | Subject | Re: [patch] zero-bounce highmem I/O |
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On Thu, Aug 16 2001, David S. Miller wrote: > From: Jens Axboe <axboe@suse.de> > Date: Thu, 16 Aug 2001 13:51:50 +0200 > > [ Hopefully this mail won't be encoded in Chinese-BIG5 :-) sorry > about that ]
Looks good :)
> The only difference between your and my tree now is the PCI_MAX_DMA32 > flag. Would you consider this? I already use this flag in the block > stuff, I just updated the two references you had. Maybe > PCI_MAX_DMA32_MASK is a better name. > > I didn't put it into my patch becuase there is no way you can > use such a value in generic code. > > What if my scsi controller's pci DMA mask is 0x7fffffff or something > like this? You don't know at the generic layer, and you must provide > some way for the block device to indicate stuff like this to you.
Then your SCSI controller will not use PCI_MAX_DMA32 but rather that particular mask? For block drivers, using 0x7fffffff for blk_queue_bounce_limit is perfectly fine too.
> That is why PCI_MAX_DMA32, or whatever you would like to name it, does > not make any sense. It can be a shorthand for drivers themselves, but > that is it and personally I'd rather they just put the bits there > explicitly.
Drivers, right. THe block stuff used it in _one_ place -- the BLK_BOUNCE_4G define, to indicated the need to bounce anything above 4G. But no problem, I can just define that to 0xffffffff myself.
> I am just finishing up the "death of alt_address" patch right now.
Excellent.
-- Jens Axboe
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