On Sat, Jan 18, 2014 at 11:59:56AM -0800, Linus Torvalds wrote: > On Fri, Jan 17, 2014 at 11:46 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > On Fri, Jan 17, 2014 at 11:22:04PM -0800, Linus Torvalds wrote: > >> On Fri, Jan 17, 2014 at 10:40 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > >> > > >> > Objections, comments? > >> > >> I certainly object to the "map, then unmap" approach. No VM games. > > > > Um... > > > > If we are going to copy that data (and all users of generic_file_splice_write() > > do that memcpy() to page cache), we have to kmap the source ;-/ > > Yeah, the kmap/kunmap we have to do. But that's a no-op on 64-bit, and > has to be done one page at a time (well, I guess you could do a > couple). > > But you can't do that *around* the default_file_splice_write(), so I > thought you meant some kind of "map into user space". And I absolutely > *detest* that kind of approach. Ouch... No, I hadn't meant that kind of insanity, but I'd missed the problem with scarcity of mappings completely... -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
