On Mon, Nov 21, 2016 at 04:26:19PM +0800, Herbert Xu wrote: > crypto: scatterwalk - Remove unnecessary aliasing check in map_and_copy > > The aliasing check in map_and_copy is no longer necessary because > the IPsec ESP code no longer provides an IV that points into the > actual request data. As this check is now triggering BUG checks > due to the vmalloced stack code, I'm removing it. > > Reported-by: Eric Biggers <[email protected]> > Signed-off-by: Herbert Xu <[email protected]> > > diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c > index 52ce17a..c16c94f8 100644 > --- a/crypto/scatterwalk.c > +++ b/crypto/scatterwalk.c > @@ -68,10 +68,6 @@ void scatterwalk_map_and_copy(void *buf, struct > scatterlist *sg, > > sg = scatterwalk_ffwd(tmp, sg, start); > > - if (sg_page(sg) == virt_to_page(buf) && > - sg->offset == offset_in_page(buf)) > - return; > - > scatterwalk_start(&walk, sg); > scatterwalk_copychunks(buf, &walk, nbytes, out); > scatterwalk_done(&walk, out, 0);
This looks fine to me if you're confident that the aliasing check is indeed no longer necessary. Another idea I had was to replace memcpy() with memmove(). But I don't want to be in a situation where we're stuck with memmove() forever because of users who probably don't even exist. Eric
