On Fri, 4 Oct 2019 at 16:03, Jason A. Donenfeld <Jason@xxxxxxxxx> wrote: > > On Wed, Oct 02, 2019 at 04:17:13PM +0200, Ard Biesheuvel wrote: > > Reimplement the library routines to perform chacha20poly1305 en/decryption > > on scatterlists, without [ab]using the [deprecated] blkcipher interface, > > which is rather heavyweight and does things we don't really need. > > > > Instead, we use the sg_miter API in a novel and clever way, to iterate > > over the scatterlist in-place (i.e., source == destination, which is the > > only way this library is expected to be used). That way, we don't have to > > iterate over two scatterlists in parallel. > > Nice idea. Probably this will result in a real speedup, as I suspect > those extra prior kmaps weren't free. Looking forward to benching it. They weren't only non-free, they were also using kmap_atomic() unconditionally, which means that these routines were running with preemption disabled even with non-SIMD crypto on non-highmem architectures.
