On Sat, 2014-03-22 at 22:23 +0000, Russell King - ARM Linux wrote: > On Sat, Mar 22, 2014 at 02:31:21PM -0700, James Bottomley wrote: > > Perhaps now might be the time to ask which are the remaining > > architectures that cannot do SG chaining and then we can fix them and > > pull the whole thing out. > > Not quite. You're making the assumption that we can be sure that all > the scatterlist users on an architecture have been converted - that's > simply not true on ARM. No I'm not, I said "now might be the time to ask which are the remaining architectures that cannot do SG chaining" I think it's time to list them so we know what work remains. I know we've got a bunch in parisc (all of our iommu code in driver/parisc - about 5 different ones - are unconverted). However, the conversion is pretty simple; it's mostly replacing sglist++ with sglist=sg_next(sglist) > We have some which have, and some which still > have not been audited. > > The cases that get us here would be old platform DMA code which walks > scatterlists handed to it from drivers - stuff like > arch/arm/mach-rpc/dma.c (which probably can cope), and drivers/scsi/arm/* > (which definitely can't because of their SCSI pointers save/restore > handling message.) I know that's one case where SG_CHAIN definitely > isn't supported on ARM. > > So, we had decided not to enable it, but this means that new stuff > isn't benefitting from this. I've recently asked arm-soc to enable > it for the modern multi-platform builds, because modern stuff really > be written with correct SG chaining in mind. OK, so lets see what the actual effort is. James -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
