Re: [Qemu-devel] [PATCH] iov: don't touch iov in iov_send_recv()

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Wen Congyang (wency@cn.fujitsu.com) wrote:
> Ping...

Hi Wen,
  I don't know the block side of stuff to review this stuff, so
I'll leave it to Kevin and Paolo.

Dave

> 
> On 05/21/2015 09:50 AM, Wen Congyang wrote:
> > Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> > ---
> >  include/qemu/iov.h |  2 +-
> >  util/iov.c         | 14 +++++++++++++-
> >  2 files changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/qemu/iov.h b/include/qemu/iov.h
> > index 68d25f2..569b2c2 100644
> > --- a/include/qemu/iov.h
> > +++ b/include/qemu/iov.h
> > @@ -75,7 +75,7 @@ size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
> >   * For iov_send_recv() _whole_ area being sent or received
> >   * should be within the iovec, not only beginning of it.
> >   */
> > -ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
> > +ssize_t iov_send_recv(int sockfd, const struct iovec *iov, unsigned iov_cnt,
> >                        size_t offset, size_t bytes, bool do_send);
> >  #define iov_recv(sockfd, iov, iov_cnt, offset, bytes) \
> >    iov_send_recv(sockfd, iov, iov_cnt, offset, bytes, false)
> > diff --git a/util/iov.c b/util/iov.c
> > index 2fb18e6..a0d5934 100644
> > --- a/util/iov.c
> > +++ b/util/iov.c
> > @@ -133,7 +133,7 @@ do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
> >  #endif
> >  }
> >  
> > -ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
> > +ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt,
> >                        size_t offset, size_t bytes,
> >                        bool do_send)
> >  {
> > @@ -141,6 +141,16 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
> >      ssize_t ret;
> >      size_t orig_len, tail;
> >      unsigned niov;
> > +    struct iovec *local_iov, *iov;
> > +
> > +    if (bytes <= 0) {
> > +        return 0;
> > +    }
> > +
> > +    local_iov = g_new0(struct iovec, iov_cnt);
> > +    iov_copy(local_iov, iov_cnt, _iov, iov_cnt, offset, bytes);
> > +    offset = 0;
> > +    iov = local_iov;
> >  
> >      while (bytes > 0) {
> >          /* Find the start position, skipping `offset' bytes:
> > @@ -187,6 +197,7 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
> >  
> >          if (ret < 0) {
> >              assert(errno != EINTR);
> > +            g_free(local_iov);
> >              if (errno == EAGAIN && total > 0) {
> >                  return total;
> >              }
> > @@ -205,6 +216,7 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
> >          bytes -= ret;
> >      }
> >  
> > +    g_free(local_iov);
> >      return total;
> >  }
> >  
> > 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK