Re: [Qemu-devel] [PATCH] char: Allow devices to use a single multiplexed chardev.

[Kusanagi Kouichi]

On 2011-04-25 15:27:20 +0530, Amit Shah wrote:
> On (Fri) 22 Apr 2011 [21:59:42], Kusanagi Kouichi wrote:
> > This fixes regression caused by commit
> > 2d6c1ef40f3678ab47a4d14fb5dadaa486bfcda6
> > ("char: Prevent multiple devices opening same chardev").
> 
> What's the regression?  How do I test it?
> 

-nodefaults -nographic -chardev stdio,id=stdio,mux=on,signal=off -mon stdio 
-device virtio-serial-pci -device virtconsole,chardev=stdio -device 
isa-serial,chardev=stdio
fails with
qemu-system-x86_64: -device isa-serial,chardev=stdio: Property 
'isa-serial.chardev' can't take value 'stdio', it's in use
Is this intended?

> > Signed-off-by: Kusanagi Kouichi <address@hidden>
> > ---
> >  hw/qdev-properties.c |    4 ++--
> >  qemu-char.c          |    5 ++++-
> >  qemu-char.h          |    2 +-
> >  3 files changed, 7 insertions(+), 4 deletions(-)
> > 
> > diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
> > index 1088a26..0eed712 100644
> > --- a/hw/qdev-properties.c
> > +++ b/hw/qdev-properties.c
> > @@ -354,10 +354,10 @@ static int parse_chr(DeviceState *dev, Property 
> > *prop, const char *str)
> >      if (*ptr == NULL) {
> >          return -ENOENT;
> >      }
> > -    if ((*ptr)->assigned) {
> > +    if ((*ptr)->avail < 1) {
> >          return -EEXIST;
> >      }
> > -    (*ptr)->assigned = 1;
> > +    --(*ptr)->avail;
> >      return 0;
> >  }
> >  
> > diff --git a/qemu-char.c b/qemu-char.c
> > index 03858d4..f08f2b8 100644
> > --- a/qemu-char.c
> > +++ b/qemu-char.c
> > @@ -199,7 +199,7 @@ void qemu_chr_add_handlers(CharDriverState *s,
> >  {
> >      if (!opaque) {
> >          /* chr driver being released. */
> > -        s->assigned = 0;
> > +        ++s->avail;
> >      }
> 
> Will just checking for handlers (fd_can_read, fd_read, fd_write not
> NULL) here help instead of this patch?
> 

That doesn't help.

> >      s->chr_can_read = fd_can_read;
> >      s->chr_read = fd_read;
> > @@ -2544,7 +2544,10 @@ CharDriverState *qemu_chr_open_opts(QemuOpts *opts,
> >          snprintf(base->label, len, "%s-base", qemu_opts_id(opts));
> >          chr = qemu_chr_open_mux(base);
> >          chr->filename = base->filename;
> > +        chr->avail = MAX_MUX;
> >          QTAILQ_INSERT_TAIL(&chardevs, chr, next);
> > +    } else {
> > +        chr->avail = 1;
> >      }
> >      chr->label = qemu_strdup(qemu_opts_id(opts));
> >      return chr;
> > diff --git a/qemu-char.h b/qemu-char.h
> > index fb96eef..ebf3641 100644
> > --- a/qemu-char.h
> > +++ b/qemu-char.h
> > @@ -70,7 +70,7 @@ struct CharDriverState {
> >      char *label;
> >      char *filename;
> >      int opened;
> > -    int assigned; /* chardev assigned to a device */
> > +    int avail;
> >      QTAILQ_ENTRY(CharDriverState) next;
> >  };
> >  
> > -- 
> > 1.7.4.4
> > 
> > 
> 
>               Amit