On Fri, 2015-01-30 at 10:33 +0100, Paolo Bonzini wrote: > > On 30/01/2015 09:12, Nicholas A. Bellinger wrote: > > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > > > This patch adds a new memcpy_fromiovec_out() library function which modifies > > the passed *iov following memcpy_fromiovec(), but also returns the next current > > iovec pointer via **iov_out. > > > > This is useful for vhost ANY_LAYOUT support when guests are allowed to generate > > incoming virtio request headers combined with subsequent SGL payloads into a > > single iovec. > > > > Cc: Michael S. Tsirkin <mst@xxxxxxxxxx> > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > > Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > --- > > include/linux/uio.h | 2 ++ > > lib/iovec.c | 27 +++++++++++++++++++++++++++ > > 2 files changed, 29 insertions(+) > > <SNIP> > > --- a/lib/iovec.c > > +++ b/lib/iovec.c > > @@ -28,6 +28,33 @@ int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len) > > EXPORT_SYMBOL(memcpy_fromiovec); > > > > /* > > + * Copy iovec to kernel, saving the current iov to *iov_out. > > + * Returns -EFAULT on error. > > Perhaps document that iov is modified, zeroing everything in [iov, > *iov_out) and possibly removing the front of *iov_out? > Sure, updated the read the following: * Copy iovec to kernel, modifying the passed *iov entries. * * Save **iov_out for the caller to use upon return, that may either * contain the current entry with a re-calculated iov_base + iov_len * or next unmodified entry. * * Also note that any iovec entries preceding the final *iov_out are * zeroed by copy_from_user(). Thank you, --nab -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
