Re: [Qemu-devel] [PATCH] net: tap: use qemu_set_nonblock

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Nov 21, 2018 at 11:57:18AM +0000, Daniel P. Berrangé wrote:
> On Wed, Nov 21, 2018 at 03:28:29PM +0400, Marc-André Lureau wrote:
> > Hi
> > 
> > On Wed, Nov 21, 2018 at 3:22 PM Li Qiang <liq3ea@gmail.com> wrote:
> > >
> > > The fcntl will change the flags directly, use qemu_set_nonblock()
> > > instead.
> > 
> > qemu_set_nonblock() will preserve the existing flags. And on windows,
> > it will register the FD to the event loop.
> > that's a reasonable thing to do, is this fixing an actual bug?
> 
> tap.c is only built with CONFIG_POSIX. Win32 is completely separate
> in tap-win32.c.  So the event loop reg doesn't apply.
> 
> I agree it is good to preserve fcntl flags though, so this patch
> looks desirable.
> 
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Sure

Acked-by: Michael S. Tsirkin <mst@redhat.com>

but really not for this release I guess as we are in freeze.
So thanks! And pls remember to ping after the release.


> 
> > 
> > >
> > > Signed-off-by: Li Qiang <liq3ea@gmail.com>
> > > ---
> > >  net/tap.c | 10 +++++-----
> > >  1 file changed, 5 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/net/tap.c b/net/tap.c
> > > index cc8525f154..e8aadd8d4b 100644
> > > --- a/net/tap.c
> > > +++ b/net/tap.c
> > > @@ -592,7 +592,7 @@ int net_init_bridge(const Netdev *netdev, const char *name,
> > >          return -1;
> > >      }
> > >
> > > -    fcntl(fd, F_SETFL, O_NONBLOCK);
> > > +    qemu_set_nonblock(fd);
> > >      vnet_hdr = tap_probe_vnet_hdr(fd);
> > >      s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
> > >
> > > @@ -707,7 +707,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
> > >                  }
> > >                  return;
> > >              }
> > > -            fcntl(vhostfd, F_SETFL, O_NONBLOCK);
> > > +            qemu_set_nonblock(vhostfd);
> > >          }
> > >          options.opaque = (void *)(uintptr_t)vhostfd;
> > >
> > > @@ -791,7 +791,7 @@ int net_init_tap(const Netdev *netdev, const char *name,
> > >              return -1;
> > >          }
> > >
> > > -        fcntl(fd, F_SETFL, O_NONBLOCK);
> > > +        qemu_set_nonblock(fd);
> > >
> > >          vnet_hdr = tap_probe_vnet_hdr(fd);
> > >
> > > @@ -839,7 +839,7 @@ int net_init_tap(const Netdev *netdev, const char *name,
> > >                  goto free_fail;
> > >              }
> > >
> > > -            fcntl(fd, F_SETFL, O_NONBLOCK);
> > > +            qemu_set_nonblock(fd);
> > >
> > >              if (i == 0) {
> > >                  vnet_hdr = tap_probe_vnet_hdr(fd);
> > > @@ -887,7 +887,7 @@ free_fail:
> > >              return -1;
> > >          }
> > >
> > > -        fcntl(fd, F_SETFL, O_NONBLOCK);
> > > +        qemu_set_nonblock(fd);
> > >          vnet_hdr = tap_probe_vnet_hdr(fd);
> > >
> > >          net_init_tap_one(tap, peer, "bridge", name, ifname,
> > > --
> > > 2.11.0
> > >
> > >
> > 
> > 
> > -- 
> > Marc-André Lureau
> > 
> 
> Regards,
> Daniel
> -- 
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