Messages in this thread | | | From | Gerd Knorr <> | Subject | Re: Does kmalloc always return address below 4GB? | Date | 5 Mar 2002 17:00:55 GMT |
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> >Look at other drivers using the DMA interfaces like the two aic7xxx > >and all of the sym53c8xx drivers, they get it right. > > Grepping for vmalloc and kmap in them turns up no hits.
Why do you want to vmalloc() memory in the scsi driver?
> computer with >4GB of RAM (CONFIG_HIGHEM) talking to a PCI card > that only does 32-bit addressing: > > pci_set_dma_mask(pcidev, 0xffffffff); > addr = vmalloc(nbytes); > /* On an x86 with >4GB of RAM, addr will be <4GB, but > __pa(addr) might be >4GB, and the system lacks > PCI address mapping harware. */
use vmalloc_32(), this one returns lowmem.
> dma_addr = pci_map_single(pcidev, addr, nbytes, direction);
This is illegal because addr is a kernel _virtual_ address. You have to get the page using vmalloc_to_page() and feed this to pci_map_page() then. With nbytes > PAGE_SIZE you probably want to build a scatterlist and use pci_map_sg().
Gerd
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