On Sun, 20 Mar 2005, Christoph Hellwig wrote: > On Wed, Mar 16, 2005 at 06:04:17PM +0100, Jens Axboe wrote: > > On Wed, Mar 16 2005, Christoph Hellwig wrote: > > > On Wed, Mar 16, 2005 at 05:53:39PM +0100, Jens Axboe wrote: > > > > The list doesn't really need dma mapping at that point, the problem here > > > > is that the driver needs to punt to pio mode because of foo. So calling > > > > pci/dma_map_* is pointless, since the CPU will have to do the transfer > > > > anyways. What the driver is really looking for at this point, is a way > > > > to map the pages in the sglist to a virtual address. > > > > > > Given that there's quite a few cases of this "problem" it would be nice > > > to have common helpers for it. Especially as it's really difficult when > > > we allow merging of sg list entries > > > > I thought about that when writing the above, but is there really more > > than one case for SCSI drivers? If there is, sure lets add the helpers. > > But I would consider it a quite rare occurence, I've never seen it > > before. > > There's lots of pio only drivers, aswell as raid drivers that need to > look into the non I/O-path command and things like iscsi.
Well, how about something like char *kmap_atomic_sg(struct scatterlist *sg, unsigned int offset, int *mapped); void kunmap_atomic_sg(struct scatterlist *sg, int mapped); The latter would just call the kunmap_atomic with the respective KM_ type. By "merging of sg list entries" above is meant, that pci_map_sg may return a number smaller than the number of elements in the original sg list because some adjacent elements were merged during the mapping? Thanks Guennadi --- Guennadi Liakhovetski - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
