Re: [PATCH] speed up SATA

Bartlomiej Zolnierkiewicz
2004-03-28T00:04:59Z

On Sunday 28 of March 2004 00:40, Jeff Garzik wrote:
> Jeff Garzik wrote:
> > That's the main limitation on request size right now... libata limits
> > S/G table entries to 128[1], so a perfectly aligned, fully merged
>
> ...
>
> [1] because even though the block layer properly splits on segment
> boundaries, pci_map_sg() may violate those boundaries (James B and
> others are working on fixing this). So... for right now the driver
> must check the s/g entry boundaries after DMA mapping, and split them
> (again) if necessary. IDE does this in ide_build_dmatable().

You are right but small clarification is needed: code in ide_build_dmatable()
predates segment boundary support in block layer (IDE never relied on it).